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Centauri Dreams returns with an essay by long-time contributor Alex Tolley. If we need to grow a much bigger economy to make starships possible one day, the best way to proceed should be through building an infrastructure starting in the inner Solar System and working outward. Alex digs into the issues here, starting with earlier conceptions of how it might be done, and the present understanding that artificial intelligence is moving at such a clip that it will affect all of our ventures as we transform into a truly space-faring species. Under the microscope here is a company called SpaceFab, as Alex explains below, and the potential of ISRU — in situ resource utilization. Emerging out of all this is a new model for expansion.

by Alex Tolley

“Asteroid Facility” – Syd Mead

To sail the heavens and reach the stars is extremely expensive.  With the technologies we can currently envisage, Earth’s GDP will need to be orders of magnitude larger to support a starship program.  Unfortunately, the Earth is likely to hit environmental and economic limits well before we reach the necessary size of a starship building GDP.  One solution is for humanity to expand into the solar system to grow the economy with the vast resources available out there [5]. Science fiction novels are replete with tales about self-reliant belters extracting wealth from the asteroids, while followed by adventurers, gold-diggers and chancers, that recapitulate the myths of the “Old West” and the US’ manifest destiny [1].  

Space Habitat – John Berkey

By the late 1970s, establishing space colonies and selling solar power to Earth [2] was the idée du jour. Allen Steele popularized that vision, regaling us with stories of men and women living and working on the high frontier [3].  In reality, the cost of transporting and housing space workers is astronomical compared to those of ocean rig workers whose jobs those high-frontiersmen emulated.  An economy supporting a wealthy, post-scarcity civilization living throughout the solar system and able to support starship exploration became more fanciful, and we focussed on scaling back our starship ambitions with 1-gram, laser-propelled, sail ships that might launch half a century hence.

Exploring the Asteroids – Robert McCall

While the prospects for humans in space dimmed somewhat, a renewed flowering of developments in AI and robotics burst onto the scene with capabilities that astonished us each year.  On the endlessly orbiting ISS, while astronauts entertained us with tricks that we have seen since the dawn of spaceflight, autonomous robots improved by leaps and bounds.  Within a decade of a DARPA road challenge, driverless cars that could best most human drivers for safety appeared on the roads.  Dextrous robots replaced humans in factories in a wide variety of industries and threaten to dramatically displace human workers. DeepMind’s AlphaGo AI beat the world’s champion GO player with moves described as “beautiful” and well within the predicted time frames.  In space, robotic craft have visited every planet in the solar system and smart rovers are crawling over the face of Mars.  A private robot may soon be on the Moon.  In orbit, swarms of small satellites, packing more compute power than a 1990 vintage Cray supercomputer, are monitoring the Earth with imaging technologies that equal those of some large government satellites. On Earth we have seen the birth of additive manufacturing, AKA 3D printing, promising to put individual crafting of objects in the hands of everyone.  

What this portends is an intelligent, machine-based economy in space.  Machines able to operate where humans cannot easily go, are ideally suited to operating there.  Increasingly lightweight and capable, and heedless of life support systems, robotic missions are much cheaper..  How long before the balance tips overwhelmingly in the machines’ favor? Operating autonomously, advanced machines might rapidly transform the solar system.

In a previous post, A Vision to Bootstrap the Solar System Economy” [4], I looked at an academic paper that laid out an idea of self replicating robots that would start harvesting lunar resources and eventually expand operations out to the asteroid belt.  The power of exponential growth to bootstrap such a system was clearly evident, allowing a relatively tiny investment to create a huge manufacturing capability of staggering size within a short time with growth rates far exceeding our current human-based economies.  An interesting idea and vision, but was anyone going to consider developing a business using that approach? A new company, SpaceFab, shares a similar vision.  The founders want to create a fleet of mining and fabrication robots that will extract raw materials from the asteroids to create refined commodities and products in space, including building more robot miners and fabricators.  A grand vision, but how do they envisage it being done?

While the original idea of asteroid mining was to extract the non-volatile resources, especially the high value platinum group metals [5], more recently the focus has shifted to volatiles, primarily water, for life support and chemical rocket fuels.  SpaceFab however, prefers the extraction of the more abundant iron and nickel, whose current value in space is principally their launch cost. Their argument for this focus is twofold.  Firstly, water is relatively rare in most near Earth asteroids (NEA) and therefore likely to be more difficult to extract from those bodies.  While common in asteroids beyond the frost-line or in dead comets [10], the delta v cost is high and journey times much longer.  Conversely, metals are far more accessible inside the frost-line with NEAs, reducing both the cost to acquire these metals and the mission cycle time.  Secondly, SpaceFab is looking to extract iron and nickel using simple, lightweight and low-cost processes like magnetic collection of material, and induction heating to melt and refine the metals.  Their view is that the path to profitability is faster with this approach than prospecting and extracting volatiles.

The OSIRIS-REx mission is NASA New Frontiers mission to return a sample of an asteroid (101955 Bennu) to the Earth. Mission cost is approximately $800 million (excluding the launch vehicle.).  – Lockheed Martin

SpaceFab believes that they might get a sample return mission to an M-type asteroid within 10 years and a mining craft 5 years later.  Their design target is for a craft just 1 MT in mass (about the same size as OSIRIS-REx), and consists of an ion engine, rock scraping tools for extracting material,  and some form of electrical induction heating to produce refined ingots.  When sufficient extraction is achieved those refined ingots could then be used as feedstock for space manufacturing.   While apparently ambitious, the concept of small craft to mine asteroids has been developed by Calla, Fries and Welch and was presented in two papers at the IAC in 2017.   Their craft were designed to be less than 500Kg.  Water in close by NEAs was their objective based on their analysis of extraction methods which indicated using microwave thermal heating.  Teleoperation from Earth was assumed and therefore an NEA within 0.03 AU was preferred.  The small size combined with a swarm model for redundancy was the most economically modeled approach to provide a large and early return on investment [15,16].For robotic craft  on deep space missions, high Isp electric engines reduce costs, as the lower propellant mass means lower launch costs.  To keep costs low, SpaceFab intends to use off-the-shelf ion engines that may be augmented by their ion accelerator technology (patent pending) that they claim boosts Isp several fold.  With the Dawn mission spacecraft’s NSTAR ion engine having an Isp of 3100s, Spacefab might hope for an augmented Isp of up to 10,000s. The addition of this accelerator unit and the solar panels to power it should increase the mass ratio performance of the craft.

So far SpaceFab’s approach seems similar to other schemes to mine asteroids. Where SpaceFab’s vision really differs is the use of ISRU (in situ resource utilization) for construction of onsite mining and fabrication tools. Rather than hauling out machine tools to an asteroid to extract and fabricate components, SpaceFab plans to reduce the mining craft’s mass, and therefore cost, by building many of the machine tools for mining and fabrication using local resources.  It is just one step further to replicate the whole craft.  This model of self replication of much of the mass of the machines is similar in concept to the robot bootstrapping paper and promises to open up exponential mining and fabrication possibilities, while making the owners quite wealthy.

Most asteroids are too far away to allow teleoperation of the sort that would work on the Moon or with close NEAs.  This rules out complex manufacturing guided by human controllers.  The intelligence needed to prospect, mine and process ores must be local.  Beyond some human oversight, these robot mining craft and fabricators will need to be highly autonomous.  This requires advanced AIs. While we are not close to that goal today, the rapid pace of development of AI software and specialized chip hardware promises to make this a reality sometime in the projected time frame.  Such craft will be able to navigate to a selected asteroid, prospect it, extract and refine metals, and then fabricate machine tools and manufacture components. SpaceFab believes that such craft could even provide a “manufacturing on demand” service in space.  On Earth we have seen the birth of additive manufacturing, AKA 3D printing, promising to put individual crafting of objects in the hands of everyone.  The technology is already being tested on the ISS to reduce the number of spare parts that must be shipped.  

Fabrication, even self-replication, is no longer a science fiction concept.  Nasa has a “FabLab” program to investigate the best ways of using that technology to facilitate spaceflight as a result of its success with 3D printing experiments on the ISS. Neil Gershenfeld’s lab at MIT has designed a method of robotic self-replication suitable for use in space.  The current proposed system can fit inside a CubeSat [14].  The basic technologies needed for SpaceFab’s vision are already in place, just requiring further development.

The eventual goal of robot miners and fabricators producing commodities and goods at a fraction of today’s prices, via massive supply expansion, may face some short term obstacles.  Low launch costs spearheaded by NewSpace companies like SpaceX could make placing raw materials in space cheaper than space mining, for cis-Lunar infrastructure.  However, space fabrication of components in situ is a useful goal, regardless of the raw material source. In the 1980s, K. Eric Drexler intended to manufacture ultra-light, aluminum solar sails in space. T. A. Heppenheimer described manufacturing trusses for solar powersat arrays using relatively dumb, machines bending and welding rolled sheets of aluminum. Grumman Aerospace had a working prototype “Composite Beam Builder” by the time Heppenheimer’s book [5] was published.  More recently, NIAC has funded space fabrication projects using more sophisticated robotic builders.  

At some point, regardless of cost, the sheer volume of resources for expanding the economy will require sourcing from space to overcome the Earth’s limitations.  Robotic mining and fabrication will then become the norm.  As with newly industrializing Earth-based economies, initial fabrication may be for simple, low value added, bulk commodity products, but eventually as capabilities increase, higher value added manufactures will be possible.

Although initially limited by key components like advanced computer chips, over the long term, self-replicating craft would evolve into Von Neumann replicators.   Philip Dick invented the term autofac for factories that could construct themselves from seeds and self replicate [6].  While Von Neumann machines are just self replicators, autofacs also generate outputs, much as honeybee colonies also produce excess honey.  Such self-replication and fabrication infrastructure could produce a vast range of products for the solar system economy.

SpaceFab’s Waypoint Telescope – engineering mockup.

To reach the goal of space mining and manufacturing without the deep pockets of a Deep Space Industries or Planetary Resources, SpaceFab intends to enter the orbital satellite observation market.  They have designed a low cost, high resolution (1 meter ground resolution) telescope that can be used both for astronomical and Earth observation purposes, using a variety of imaging sensors and filters that offer the range of imaging outputs suitable for both markets. Currently they are crowd-funding their initial prototype telescope which will be followed by a flight ready telescope for a 2019 launch.  By launching a fleet of such telescopes, they expect to penetrate this market by offering the lowest price imaging and analysis services.

This observation service would then produce the profits needed to develop the asteroid mining craft and bootstrap the space fabrication business. Interestingly, SpaceFab currently has no intention of using these observation satellites to prospect for suitable asteroids as DSI intends, but rather to use existing information to enable a mission to an M-type NEA.   As this information will not be detailed enough for detecting higher quality ores, the spacecraft will need to be smart enough to do their own prospecting on arrival at an asteroid.  SpaceFab speculates that in the near term, the value of fairly pristine asteroidal material may be higher for research than its commodity price and may offer a faster path to early profitability.

Once mature, self-replicating fabs promise a future that has vastly expanded horizons and  implies a post-scarcity economy.  Once such seed factories become ubiquitous, there is no reason why they could not venture to other solar systems and replicate there.  Even if slow, perhaps travelling at 1/100th c, they would reach the nearer stars in half a millennium, creating all the materials and habitats for humans to occupy.  This is the model that Asimov’s “spacers” envisaged for themselves [7], their robots preparing the way for them to follow.  The colonization process would be with a wave of machines preparing star systems for the following human starships.

It is a dazzling future to contemplate if it unfolds this way.

References

  1. Anderson, Poul. Tales of the Flying Mountains. Tom Doherty Associates, 1970.
  1. O’Neill, Gerard K. The High Frontier: Human Colonies in Space. Morrow, 1977.
  1. Steele, Allen M. Sex and Violence in Zero-G: the Complete Near-Space Stories. Meisha Merlin Pub., 1998.
  1. Tolley, Alex “A Vision to Bootstrap the Solar System Economy”   https://www.centauri-dreams.org/?p=36963
  1. Lewis, John S. Mining the Sky: Untold Riches from the Asteroids, Comets, and Planets. Addison-Wesley, 1998.
  1. Heppenheimer, T. A. Toward Distant Suns. Stackpole, 1979.
  1. Dick, Philip K. “Autofac.” The Collected Stories of Philip K. Dick, Subterranean Press, 2010.
  1. Asimov, Isaac. The Robots of Dawn. Bantam Books, 1994.
  1. SpaceFab  http://www.SpaceFab.us/
  1. Graps, A et al. “In-Space Utilization of Asteroids – Answers to Questions from the Asteroid Miners”, ASIME 2016: Asteroid Intersections with Mine Engineering, Luxembourg. September 21-22, 2016. arxiv.org/abs/1612.00709
  1. Brophy, J.,  et al. “Asteroid Retrieval Feasibility Study” (2012).  Keck Institute for Space Studies, Caltech, JPL.   kiss.caltech.edu/final_reports/Asteroid_final_report.pdf
  1. Welch, C., et al. Asteroid Mining Technologies Roadmap and Applications (ASTRA)” (2010) , International Space University          isulibrary.isunet.edu/opac/doc_num.php?explnum_id=73
  1. Mazanek, D. “Asteroid Redirect Mission Concept: A Bold Approach for Utilizing Space Resources.” Acta Astronautica, Pergamon, 23 July 2015, www.sciencedirect.com/science/article/pii/S0094576515002635.
  1. Langford, Will, et al. “Hierarchical Assembly of a Self-Replicating Spacecraft.” 2017 IEEE Aerospace Conference, 2017, doi:10.1109/aero.2017.7943956.
  1. Calla, P., Fries, D., Welch, C. “Analysis of an Asteroid Mining Architecture utilizing Small Spacecraft”,  IAC 2017
  1. Calla, P., Fries, D., Welch, C. “Low-Cost Asteroid Mining Using Small Spacecraft”, IAC 2017

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Closing Remarks at TVIW 2017

I know I said I wouldn’t post for a bit, but because I’ve just given my closing remarks at the Tennessee Valley Interstellar Workshop, they are ready to go for publication, and I thought I would go ahead and publish them here. I did much of the actual writing for this at the conference (where I still am), so there may be a few typos. I haven’t inserted the affiliations of the speakers, either, but I’d like to go ahead and get this up. My plan, once I’ve taken care of other obligations in the next ten days or so, is then to return to TVIW with greater focus and look at specific papers that caught my eye and the ways they fit in with the larger interstellar picture. For more background on the speakers here until then, check the TVIW 2017 Symposium page. I also didn’t mention the excellent workshop sessions in this talk because they had just been summarized immediately before my own talk. But more on them as well as other TVIW observations when I return to regular Centauri Dreams posts. This should be around mid-October.

I want to thank Les Johnson and the conference organizers at TVIW, Tau Zero and Starship Century for the opportunity to make this presentation, and for the huge outlay in time and energy they devoted to the event. That includes our workshop leaders and participants who carried the original workshop notion forward. What I now hope to do is give an overview of what we have done here and what it signifies.

Somewhere around the 6th Century BCE, a man named Lao Tzu, an almost legendary philosopher and writer, purportedly produced the book known as the Tao Te Ching, a fundamental text of Taoism and Chinese Buddhism. This year’s Tennessee Valley Interstellar Workshop arrived made to order for Taoist thought, with its theme “Step by Step: Building a Ladder to the Stars.” Because for years I’ve used as the line on my digital signature the Tao Te Ching’s aphorism: “You accomplish the great task by a series of small acts.” Confucius, who may have known Lao Tzu, would echo the same philosophy.

As anyone paying attention to this year’s sessions learned at the beginning, many of the acts we are trying to accomplish are anything but small. A 100 GW laser array is not small either in concept or in physical dimension. A sail five meters to the side is small by many earlier standards, but what we discuss doing with it, a mission to the nearest star, is not small, nor is the exploration of the outer Solar System — with precursors fueled by fusion or driven by plasma sail — a small accomplishment. But conceptualizing each of these things, one at a time, that is a series of small steps, and we need many such steps.

The emergence of Breakthrough Starshot clearly changes the game for everyone in the interstellar community. We have a congressional subcommittee report that ‘encourages NASA to study the feasibility and develop propulsion concepts that could enable an interstellar scientific probe with the capability of achieving a cruise velocity of 10 percent of the speed of light.” I doubt seriously that that phrasing would have emerged without the powerful incentive of the funding provided by Breakthrough, nor would the Tau Zero Foundation’s recent grant.

We’re on new terrain that is a long way from where we once were, in the days when there were few interstellar meetings as such and most discussions among those of an interstellar bent happened at occasional get-togethers in meetings on largely different subjects. Today we have a community and, if it is one with a pointing problem in terms of how often it meets and how well it stays focused, it is at least one with high energy levels and a steep drive to succeed.

TVIW 2017 gave us a range of focused sessions which I have chosen to group, trying to avoid being too arbitrary, into loose themes. Pete Klupar gave us the Breakthrough overview, which includes the welcome and related work of both Breakthrough Watch and Listen, a reminder that we must gain more information about the target of our mission, and indeed decide whether there may not be an even more attractive target near Centauri A or B. The welcome news that the RFP process has begun with work on the project’s laser array shows us a community with an actual interstellar project seriously defining the parameters of a mission.

Here we are in the larger realm of vision, as Andrew Siemion reminds us when he tells us that we search for ourselves as we venture to the stars. We also, whether or not we send Starshot sails on their journeys in 40 or 50 years, define the limits of our present technology and infuse the entire enterprise with an unprecedented prospect of well funded trade studies. The interstellar enterprise advances whether or not Starshot’s sails launch to Centauri, and who can say what spinoffs we won’t gain from the effort in the interplanetary arena with its tools.

On the matter of overview, let me mention Marc Millis’ discussion of the Tau Zero grant from NASA, which as I mentioned derived from the impetus of the Starshot initiative. Comparing propulsion approaches to take us through what Millis calls the era of precursors, the era of infrastructure and the non-extrapolatable future helps us identify the critical issues that need study, just as Starshot itself helps us locate, one by one, the major problems we need to solve for a specific mission concept. What we do need to be wary of is premature lock-in when competing methods for doing interstellar missions remain very much on the table.

In the realm of hard decisions and trade studies that illuminate them, Kevin Parkin showed us a system model that allows Starshot to study not only a Centauri mission at 20 percent of c, but also a precursor mission to a closer objective and a 70 km/sec ground vacuum tunnel test facility. It is heartening to realize that Parkin’s system has been used to conduct trade studies since March of 2016.

Meanwhile, the inputs from the broader community continue. Al Jackson showed us an analysis of trajectories for a Starshot probe, and we’re reminded by Benjamin Diedrich, who has been working with the NEA Scout mission, that we can learn much from a mission with a much different objective, and one with the ability to apply guidance and control forces that our Centauri-bound sail will be unable to muster. Congratulations to Diedrich and particularly Les Johnson for the recent successful deployment tests of the NEA Scout sail.

I want to also mention in the realm of trade studies and laboratory work the importance of the kind of measurements George Hathaway discussed for any work of this kind. Looking at problems in testing high voltages in high vacuum at cryogenic temperatures, Hathaway showed the measurement pitfalls that can ensnare experimenters, hard lessons to be kept in mind at all times by those who are evaluating propulsion technologies both understood and exotic.

Starshot’s mission components were a major factor in our deliberations. That 100 gigawatt laser array that Robert Fugate described can put something on the order of 30,000 g’s on the sail if we can get it to operate, despite the major issues of laser phase noise, optical path length differences, atmospheric fluctuation and pointing accuracy. We are considering a sail that goes from Earth orbit to 10 times the distance of the Moon in a matter of hundreds of seconds.

Can we make this happen? Starshot fails if it does not, and it fails if Jim Benford and those working with him cannot come up with a sail that can withstand the huge forces to be slammed into it. Here I want to pause to mention the rich sail background on display at the conference. The Benford brothers did the first work on sails in the laboratory — and as far as I know — the first actual tests of beamed sails, some 16 years ago. In the audience, we had Gregory Matloff, a distinguished figure in sail history who has been examining their prospects for decades.

Geoffrey Landis has published key papers on sail materials, and although his role in this TVIW was to discuss the Solar Gravity Lens, his contributions help us as we look toward possible sail materials and shapes within the Starshot envelope. The welcome presence of Giancarlo Genta reminds us of the tremendous contribution of the Italian sail effort through Project Aurora and other work in the 1990s. The need for the kind of sail test facility Jim Benford so carefully described is obvious and one hopes it will be the target of quick action, especially with the new wave of RFPs starting to translate the concept into reality.

Phil Lubin’s analysis of directed energy as the enabler for interstellar missions, beginning with a NIAC Phase 1 study under the name Starlight, led to Pete Worden’s making the connection with sails as a possible driver for a Centauri mission with a wafer scale payload. I was sorry that Mason Peck wasn’t here to participate in the discussion given his role in ‘spacecraft on a chip’ through his work at Cornell, but Lubin reminded us that an infrastructure like this can do much more than drive chip spacecraft. It can become a huge factor in planetary defense, in power beaming to Earth, in space debris removal and beamed transport within the Solar System.

Giancarlo Genta presented a preliminary analysis of inflated spherical sails of the kind recently proposed by Avi Loeb and Zac Manchester for Breakthrough Starshot. Working at far lower power levels for beam intensity, Genta found that an inflated sail essentially holds its shape under beam power, using a one meter diameter sail at 30 g’s acceleration. Further testing at increased power levels approximating Starshot are ahead. Key questions include whether hitting a sail with 30,000 g’s will not both deform and spin the sail, although as Genta pointed out, the sail can be abandoned for the duration of cruise if it can be brought safely up to speed.

I heard several people in the audience calling communications back to Earth the biggest challenge for Starshot, and although Dr. Fugate might disagree, I have to say that David Messerschmidt’s talk on data return was sobering. We have to make up 7 orders of magnitude of signal power when compared to our outer Solar System missions, perhaps a doable proposition if we allow decades for data return. We also deal with formidable issues of background radiation, pointing accuracy, atmospheric turbulence and scattering, and optical losses. All these factors push an increase in aperture area to 565 meters.

Our communications and imaging discussion, though, also takes in Slava Turyshev’s work on imaging an exo-Earth with the Solar Gravitational Lens. Clearly, getting a good idea of our target from a technology that could allow images of 1000 x 1000 pixels would be an outstanding precursor in its own right, and one that could be used at distances up to 30 parsecs if we can make it work. Geoff Landis’ reservations about the Gravity Lens don’t question its potential but do make us ask how likely we are to make it work and deliver genuinely useful information.

We got into these matters at the Sagan session on the 550 AU mission that Claudio Maccone has called FOCAL, where Landis, Turyshev, Greg Matloff and Pontus Brandt debated the issue. It should be kept in mind that some of Maccone’s recent work on the lens has shown the potential for communication, a feature that, if it could be realized, would suddenly turn many of the issues David Messerschmidt examined on their head. Thus, if it could be determined a lensing option is workable, an early Starshot mission to explore this region is a possibility.

Let me also mention the Sagan session on detecting life through biosignatures in planetary atmospheres in which I spoke along with Greg Benford and Angelle Tanner. This is by way of looking at what we can learn about nearby stars, the fact being that nearby red dwarfs are going to be under intense scrutiny by the James Webb Space Telescope, and we have the possibility of detecting gases like oxygen and methane which, if found together, offer us a strong indicator of some kind of metabolism. Tanner’s analysis of planet finding techniques in a later session took us through the range of methods available, ranging from radial velocity to direct imaging and transits, particularly in terms of distinguishing stellar noise from terrestrial mass planets.

We moved into the realm of other interstellar precursor missions with Pontus Brandt’s discussion of probe missions to 200 AU up to 1000 AU. This gets us into virgin territory, for going to this distance puts us into the relatively pristine interstellar medium. Quaoar lines up as an interesting target along the way because of what it may tell us about the KBO population, but we also would learn a great deal about dust distribution within the system, seeing the heliosphere from outside as we see similar astrospheres around other stars. Brandt’s comments on how we manage long-term missions ring true in the era of decadal data return from a Starshot mission and destinations that may require more than a single lifetime.

Gary Pajer’s take on precursors would use the Princeton Field Reversed Configuration machine to reach out to that magical 550 AU target, where the lens effects begin, with a mission time of 13 years, or 18 if we choose to stop. Using this technology, an Alpha Centauri flyby becomes feasible within 550 years, with both power and propulsion generated by a single engine.

Could we do this with a solar sail mission? Olga Starinova asked that question, noting a close solar flyby based on recent studies by Greg Matloff, Les Johnson, Claudio Maccone and Roman Kezerashvili to reach the inner Oort Cloud within 30 years. And Stacy Weinstein-Weiss discussed a key interstellar question: Why is science return from an interstellar mission better than local studies from Earth? Here, we learned about the unique science measurements that would be performed en route to the exoplanet, including the outer regions of our solar system, the Oort Cloud, the local interstellar medium, and the astrospheric environment around the host star. Perhaps trumping all of these is the search for life with in situ measurements.

Richard London and James Early helped us understand the dust impact hazard, which they believe will not threaten a sail, but of course our concern is likewise with the payload, which must be protected at all costs. London and Early used the HYDRA code for inertial confinement fusion in this work to study how we might reduce risks using optimal materials on a fast-moving craft’s leading side, with leading thin foil to atomize dust grains. Robert Freeland pointed out to me that one of Jeff Greason’s plasma magnet sails, discussed in a moment, could also serve as a useful shield.

On useful precursor technologies, Sandy Montgomery provided a way to avoid growth in the boom diameter and mass of sails as we move toward larger-scale missions by using what he calls a ‘space tow architecture,’ a train of gossamer sails integrated with a tension truss column. The advantages: We get much larger sails without growth in boom diameter and mass, using lightweight longeron filaments to connect a stack of smaller sails, much like a tandem kite.

I had mentioned to Pete Worden in a recent online exchange that I had seen several small sail analyses springing up and asked if they had any connection with Starshot. His answer was that they didn’t, but as he put it, the more the merrier given the magnitude of the problem. Thus it’s tremendously heartening to see the outgrowth of sail ideas that may eventually influence Starshot or, more likely, feed into designs outside of immediate interstellar goals that could play into our move toward the space-based infrastructure we need here in our system.

Thus Grover Swartzlander’s analysis of diffractive meta-sailcraft, which proposes that we look more carefully at diffractive sails, which absorb little light — a key issue for beamed sails — and have none of the re-radiation problems of reflective materials. Moreover, we might recycle photons to multiple sail layers if we can develop the right broadband space-qualified diffractive films.

TVIW 2017 was marked by its focus on sail technologies, due to all the factors I’ve already mentioned, but of course we have other options to consider. Jason Cassibry talked about the problems of solid state nozzles when dealing with pulsed fusion and fission/fusion hybrids for rapid precursor missions, the primary issues being erosion and wall heating. He showed us a 3D plasma simulation of a pulsed magnetic nozzle crafted for z-pinch propulsion.

Pauli Laine examined fission fragment possibilities, given the fact that uranium fission releases 81 percent of its energy in the form of kinetic energy. The escape of fission fragments rises when particle size decreases, so low density fissile material like americium or curium comes into play, with the escaping fission fragments being used as rocket propulsion. As Laine noted, fission fragment advocates also have to contend with fuel production — how to produce enough of the needed materials — as well as daunting issues of using such rockets safely.

Antimatter appeared in two sessions this year, with Gerald Jackson describing crowdfunded ongoing experimentation into antimatter production. Jackson would like to see antimatter emerge at a rate of at least 1 gram per year, a startling figure given that I can remember when NASA gave a figure of $62.5 trillion per gram of antihydrogen. Measure this against a Fermilab production rate of 2 nanograms per year. If we can do this in a way that is economically feasible we have the option of missions like the antimatter sail that Jackson and Steve Howe, also at Hbar, has developed through NIAC work. Jackson also examined antimatter storage possibilities through diamagnetic levitation.

Antimatter storage was the key of Marc Weber’s talk, which looks at the problem of controlling space charge, the repulsive force of all those stored charges in the fuel we would like to use. Weber is experimenting with storing electrons in a massively parallel micro-array of tubes in a 7-tesla magnetic field, seeking to discover the possible configurations in trap arrays. Everyone in the interstellar community from Les Shepherd and Robert Forward on has pondered the energetics of antimatter rockets, which still face the daunting storage and production issues Weber and Jackson have explored.

A bit less exotic but with exciting potential of its own is the plasma magnet sail described by Jeff Greason. Here we can imagine deploying magsails for braking against the interstellar medium as an interstellar probe enters a destination system, achieving orbit around the target star using the stellar wind. But Greason pointed out that such technologies are likewise ideal for precursor missions to 1000 AU, for example, and conceivably, using local beamers, within braking systems for a fast mission infrastructure inside the Solar System including cycling systems to Mars. Greason considered using particle beams and even fusion pellet delivery to the sail.

I should mention that a Sagan session also explored flyby vs. deceleration with the help of Jackson, Stacy Weinstein-Weiss and Gerald Jackson, along with David Messerschmidt. The deceleration problem looms large. If we do get Starshot probes to Proxima Centauri, the imagery we receive may well make clear the need for a sustained presence in that interesting system. The payoff, as Weinstein-Weiss made clear, would be in the search for extraterrestrial life, where we may need all the resources we can muster to verify a detection.

Talking about interstellar mission concepts reminds me inescapably of a loss we suffered this year in science fiction writer Jerry Pournelle. Familiar, I think, to most of us here, Jerry explored numerous interstellar schemes including beamed sails (early on), and in Footfall used Orion technology to save the species.

Because Larry Niven wrote Footfall with Pournelle, I want to mention how pleased I was to be able to shake his hand at long last. Larry brought a whole new dimension to my science fiction reading back in the early 1970s with short stories and the novel Ringworld. What a compliment to TVIW to have Larry along with writers Geoff Landis, James Cambias, Greg Benford and Alan Steele here for tonight’s writers’ panel, not to mention our host Les Johnson himself. About Steele, I want to say that I’ve read Arkwright twice, and if you don’t know the novel, you need to acquire a copy immediately, as it addresses the issues a small community of devoted advocates face when trying to do something as outlandish as build vehicles that can move between stars.

The valedictory theme continues: Let me also mention that this year we lost Jordin Kare, an innovative physicist who came up with ideas like SailBeam, a stream of micro-sails delivered to a receding starship as a form of propulsion, and the Bussard Buzz Bomb, as he called it, a starship that came up to speed through collision fusion with a string of pellets that had been laid out along a predetermined track. I never met Jordin, but he spent a lot of time on the phone with me when I wrote my Centauri Dreams book, and I think the field is diminished by his passing.

The infrastructure theme emerged several times at this year’s sessions, with Tracie Prater looking at NASA’s In-Space Manufacturing Project, under the theme Make It, Don’t Take it. And it only makes sense as we contemplate long-term manned missions that we look at manufacturing and recycling parts on demand, using the ISS while we can, before its 2024 deorbit, as a testbed. We learned about NASA’s plans for a multi-process fabrication laboratory called FabLab, with current experiments on the ISS pointing to a robust future for assembly of materials in space with 3-D printing technology.

Jon Barr told us about the United Launch Alliance’s robust work with ACES (Advanced Cryogenic Evolved Stage) and XEUS, a vertical-landing, vertical-takeoff lunar lander demonstrator. Can we use these refuelable, reusable technologies in company with the Vulcan booster to establish what will become trade routes to Cislunar space? The idea here is connecting Low Earth and Geostationary Orbits with Earth Moon L1 and the lunar surface. The goal: A robust Solar System economy, which will eventually translate our early interstellar precursors like Starshot into a longer-term framework of exploration and perhaps colonization.

Our leadership panel included Rep. John Culberson, whose language we’ve already discussed regarding a NASA inquiry into interstellar prospects to coincide with the anniversary of the Moon landing in 2069. Also Congressman Brooks of Alabama, Lt. General Kwast and Paul McConnaughey, who directs Marshall Space Flight Center. It was rousing to hear the energy in Rep. Culberson’s voice as he described missions like Europa Clipper and the possibilities of the Space Launch System. A takeaway was his belief that the discovery of life, either in our system at Europa or Enceladus, or in biosignatures in an exoplanet atmosphere, will be a civilization-changing discovery that ignites public support for future exploration.

But it was also sobering to consider the budgetary dilemmas of ever-rising deficits and accumulating national debt. Lt. Gen. Kwast emphasized that expansion into space demands we take our values with us even as we plan missions to ever more distant targets. The panelists’ responses to Pete Klupar’s concerns over installations like the Starshot 100 GW laser show that we still have many policy questions to answer as private initiatives like these go forward.

Can we get beyond bureaucracy and current cultural fatigue to expand the realm of values responsibly? Brent Ziarnick reminded us that interstellar technology presents us with the most daunting energies human beings have ever thought to develop. The analogy with nuclear energy is clear, and fortunately supported by deep scholarship. Our preoccupation with nuclear gloom, part of Sheldon Ungar’s ‘dynamic oscillation’, as Ziarnick described, ended Project Orion and threatens our development of nuclear power options as a positive tool for exploration.

Is METI likewise an ethical issue? Kelly Smith asks whether scientists are up to the challenge of dealing with broadcasting to the stars, given that this is a matter that potentially involves the entire species. METI may be low risk, but the risk is not zero, and that risk involves the survival of the entire species. Or what about the ethics of sending humans to the stars?

For we may discover that exoplanets are not empty, but filled with life. And given the fact that we use but 21 specific amino acids to build our proteins — and that there are some 300 naturally occurring amino acids — we cannot know what life may choose to use. Perhaps, as Ken Roy reminds us, we might look for lifeless worlds on purpose, seeking places we can terraform.

We’re now looking at issues of humans among the stars, a future that could involve vast worldships taking human populations to distant systems. Ore Koren discussed the vital question of how we reduce conflict in a closed environment in which causes of violence are numerous. Koren used large datasets to look at historical examples of violence, along with strategies by which we might reduce problems like lack of external ideas and migration. The result: Our worldship emerges as multicultural and semi-centralized, a hybrid of Sweden and Singapore.

James Schwartz worked similar turf but examined the ethics of worldship travel itself. Are colonists on dubious ground imposing a worldship future on their children? Perhaps not, but the real question becomes, should we put parents on worldships in the first place? Schwartz reminded us of the need for sufficiently large crews, and the fact that we will use extraterrestrial settlements much closer to home to learn valuable lessons before embarking starward.

And there we are, TVIW 2017. Thank you all for the opportunity to listen to and learn from your deliberations. If there is one thing that the interstellar community has taught me, it is that scientists working at the top of their form are willing to listen to questions and explain their work to writers like me, and to put breathtaking concepts out to a receptive and growing audience like those who gathered here. This is a mission that all of you make possible, and while it may seem less dazzling than a Starshot, it is vital in making our interstellar effort a planet-wide affair.

I close by returning to Lao Tzu: “To avoid disappointment,” says the Tao Te Ching, “know what is sufficient. To avoid trouble, know when to stop.”

I’m done.

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Posting Slowdown

An interruption that can’t be avoided. I never realized that so many non-Centauri Dreams obligations were about to converge this fall, but it’s now clear I won’t be able to keep the site stocked with new stories for the next couple of weeks. I’ll do my best to keep up with comment moderation during this period, though there may be interruptions. See you later in the month when things get a bit more normal.

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Eduardo Bendek’s ACEsat, conceived at NASA Ames by Bendek and Ruslan Belikov, seemed to change the paradigm for planet discovery around the nearest stellar system. The beauty of Alpha Centauri is that the two primary stars present large habitable zones as seen from Earth, simply because the system is so close to us. The downside, in terms of G-class Centauri A and K-class Centauri B, is that their binary nature makes filtering out starlight a major challenge.

Image: The Alpha Centauri system. The combined light of Centauri A (G-class) and Centauri B (K-class) appears here as a single overwhelmingly bright ‘star.’ Proxima Centauri can be seen circled at bottom right. Credit: European Southern Observatory.

If we attack the problem from the ground, ever bigger instruments seem called for, like the European Southern Observatory’s Very Large Telescope in conjunction with the VISIR instrument (VLT Imager and Spectrometer for mid-Infrared) that Breakthrough Initiatives is now working with the ESO to enhance. Or perhaps one of the extremely large telescopes now in the works, like the Thirty Meter Telescope in Hawaii, or the Giant Magellan Telescope in Chile.

And if we did this from space, surely it would be an expensive platform. Except that ACEsat wasn’t expensive, nor was it large. It was designed to do just one thing and do it well.

While NASA turned down Bendek and Belikov’s idea for Small Explorer funding, the striking thing is that it would have fit that category’s definition. ACEsat was designed as a 30 to 45 cm space telescope (you can see a Belikov presentation on the instrument here, or for that matter, read Ashley Baldwin’s ACEsat: Alpha Centauri and Direct Imaging). The small instrument now being proposed by an initiative called Project Blue builds on many of the ACEsat concepts. It would run perhaps $50 million even though the original ACEsat was a $175 million design.

In other words, compared to the $8 billion James Webb Space Telescope, Project Blue’s instrument is almost inexpensive enough to be a rounding error. A privately funded initiative out of the Boldly Go Institute, in partnership with the SETI Institute, Mission Centaur, and UMass Lowell, the telescope shows its pedigree both in its low cost and big scientific return. It seems the ACEsat concept is just too good to go away.

So now we have Project Blue, which is all about seeing the blue of an Earth-like world around one or even both of the Sun-like stars of the Alpha Centauri system. No one discounts the value of the planet already discovered around Proxima Centauri, but the project hopes to find an Earth 2.0, a rocky planet in a habitable zone orbit around a star like our own. That would mean no tidal locking, no small red dwarf primary, and a year measured in months rather than days.

Image: An Earth-like planet around one of the primary Alpha Centauri stars, as simulated by Project Blue.

The project’s new Indiegogo campaign has been set up to raise $175,000 to help establish mission requirements, including the design of an initial system architecture to which computer simulations can be applied by way of testing ideas and simulating outcomes. The launch goal of 2021 is ambitious indeed, as is the low $50 million budget profile, but the project’s backers believe their work can leverage advances in the small satellite industry and imaging systems to pull it off. An explicit goal is to engage the public while tapping the original NASA work.

The project’s connection to NASA is in the form of a cooperative agreement explained on the Indiegogo site:

The BoldlyGo Institute and NASA have signed a Space Act Agreement to cooperate on Project Blue, a mission to search for potentially habitable Earth-size planets in the Alpha Centauri system using a specially designed space telescope. The agreement allows NASA employees – scientists and engineers – to interact with the Project Blue team through its mission development phases to help review mission design plans and to share scientific results on Alpha Centauri and exoplanets along with the latest technology tests being undertaken at NASA facilities. The agreement also calls for the raw and processed data from Project Blue to be made available to NASA within one year of its acquisition on orbit via a publicly accessible online data archive. The Project Blue team has been planning such an archive for broadly sharing the data with the global astronomical community and for enabling citizen scientist participation.

And I notice that Eduardo Bendek is among the ranks of an advisory committee (available here) that includes the likes of exoplanet hunters Olivier Guyon, Debra Fischer, Jim Kasting and Maggie Turnbull. But have a look at the advisor page; every one of these scientists is playing a significant role in our discovery and evaluation of new exoplanetary systems.

Thus we can say that ACEsat lives on in this new incarnation that will benefit from the input of its original designers. The spacecraft would spend two years in low Earth orbit accumulating thousands of images with the help of an onboard coronagraph to remove light from the twin stars, along with a deformable mirror, low-order wavefront sensors, and control algorithms to manage incoming light, enhancing image contrast with software processing methods.

Unlike the major observatories we’re soon to be launching — not just the James Webb Space Telescope but the Transiting Exoplanet Survey Satellite (TESS) — the Project Blue observatory will be dedicated to a single target, with no other observational duties.

A photograph of an Earth-like planet 40 trillion kilometers away gives us a sense of the changes in scale that have occurred since Voyager 1’s ‘pale blue dot’ photograph. But we already knew that Earth was inhabited. Now, gaining spectral information about a blue and green world around a nearby star would allow us to determine whether biosignature gases could be found in its atmosphere, potential signs of life that would mark a breakthrough in our science. The degree of public involvement assumed in the project makes the quest all the more tantalizing.

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On the GW170814 Gravitational Wave Detection

What we get with yesterday’s gravitational wave announcement isn’t a breakthrough in itself. After all, this is not the first but the fourth detection of a black hole merger, so as we enter the era of gravitational wave astronomy, we’re beginning to build our catalog of exotic objects.

But the gravitational wave known as GW170814 is significant because of the addition of the Virgo Gravitational-Wave Observatory to our toolkit. We ramp up our capabilities at locating the objects we detect in the sky when we factor in this new detector. Thus Chad Hanna (Penn State), who served as co-chair of the group within LIGO (Laser Interferometer Gravitational-Wave Observatory) that made all previous detections:

“It is our hope to one day detect gravitational waves and to simultaneously observe the source of the gravitational waves with conventional telescopes so that we might learn even more about what causes the gravitational waves. In order to do that, we need to know where to look. LIGO and Virgo together allow us to pinpoint the gravitational wave source in the sky far better than before, which will dramatically improve our chances of capturing the gravitational wave source with other telescopes.”

Image: Top row: Signal-to-noise ratio as a function of time. The peaks occur at different times in different detectors because gravitational waves propagate at the finite speed of light; this causes the signal to reach the detectors at different times. GW170814 arrived first in LIGO-Livingston, then 8 ms later in LIGO-Hanford and 6 ms after that in Virgo. Middle row: Time-frequency representation of the strain data. The brighter a given pixel in any of the three 2D-maps, the larger the signal at this particular time and frequency with respect to the expected noise level. Note the characteristic “chirp” pattern of increasing frequency with time. Bottom row: Strain time series with the best waveforms selected by the matched filtering (black solid curves) and unmodeled search methods (gray bands) superimposed. Credit and copyright: LIGO Scientific Collaboration and Virgo Collaboration.

Gravitational wave astronomy is less than two years old, but we’re adding substantial resources to the investigation with the addition of the Virgo detector. Located near Pisa, the Italian effort involves more than 280 physicists and engineers in 20 different European research groups. The Virgo detector took data jointly with the two LIGO observatories, one in Livingston, Louisiana and the other at Hanford in Washington state, in a network that also included contributions from the Anglo-German GEO600 instrument near Hanover.

The network observed GW170814 on August 14, only two weeks after the Virgo detector began taking data. Subsequent analysis showed that the event marked the merger of two black holes of 31 and 25 solar masses respectively, occurring at a distance of 1.8 billion light years. The newly produced black hole is thought to have 53 times the mass of the Sun, with three solar masses being converted into gravitational wave energy during the coalescence of the constituent black holes.

And here is where the triangulation comes in. The gravitational wave arrived at the Livingston detector some 8 milliseconds before the LIGO detector at Hanford, and some 14 milliseconds before reaching the Virgo detector. Combined arrival time delays allows the direction toward the source to be determined. Researchers are saying they can trace it down to a patch of 60 square degrees in the southern sky between the constellations Eridanus and Horologium. Moving from a two- to three-detector network shrinks the volume of sky likely to contain a source by more than a factor of 20, according to this LIGO Scientific Collaboration news release.

Image: The Virgo Observatory. Credit: The Virgo collaboration/CCO 1.0.

The search for an analog to the gravitational wave event produced no detection at electromagnetic wavelengths, although 25 observatories searched at wavelengths ranging from gamma, optical, infrared, x-ray, and radio as well as neutrino emissions. The lack of an electromagnetic detection was not surprising, because although collisions of neutron stars are thought likely to produce light emissions as well as gravitational waves, black hole mergers produce gravitational waves but not light.

Scientists at the Albert Einstein Institute in Potsdam and Hanover ruled out random noise fluctuations, finding the signal to be real with a probability of more than 99 percent. The Hanover team developed many of the software algorithms used in the analysis of LIGO data.

A third observatory ensures that future detections will be accompanied by a search for the source at all these wavelengths as we begin to extend gravitational wave astronomy into events beyond black hole collisions.

“This is just the beginning of observations with the network enabled by Virgo and LIGO working together,” says David Shoemaker of MIT, LIGO Scientific Collaboration spokesperson. “With the next observing run planned for Fall 2018 we can expect such detections weekly or even more often.”

The paper on this event, accepted at Physical Review Letters, is LIGO Scientific Collaboration and The Virgo Collaboration, “GW170814 : A three-detector observation of gravitational waves from a binary black hole coalescence” (available online).

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The Milky Way as an Outlier

How ‘normal’ is the Milky Way? It’s an interesting question because as we look out into a visible universe filled with perhaps 100 billion galaxies, we base many of our models for their behavior on what we know of our own. That this may not be the best way to proceed is brought home by a much smaller study, the comparison between our Solar System and what we’ve been finding around other stars. Finding Solar System analogs has proven surprisingly difficult, although older models assumed outer gas giants and inner rocky worlds as a common pattern.

Thus I am keeping an eye on a survey called Satellites Around Galactic Analogs (SAGA), which is looking into galaxies with smaller satellite galaxies. We’re only in the early days of this survey, with eight galaxies now examined in a new paper from lead author Marla Geha (Yale University). But the goal is 100 galaxies, with 25 of these studied within the next two years.

Image: A three-color optical image of a Milky Way sibling. Credit: Sloan Digital Sky Survey.

Even now, however, the results are intriguing. It turns out that the satellite galaxies of the Milky Way are far more sedate than those in other galactic systems comparable in luminosity and environment. It’s not uncommon for ‘sibling’ galaxy satellites to be producing new stars, but the Milky Way’s satellites are generally inert. Like our Solar System, our galaxy too may have its quirks.

“We use the Milky Way and its surroundings to study absolutely everything,” said Geha, “Hundreds of studies come out every year about dark matter, cosmology, star formation, and galaxy formation, using the Milky Way as a guide. But it’s possible that the Milky Way is an outlier.”

Like the study of exoplanet atmospheres we looked at yesterday, comparative surveys like these are essential for placing what we see around us in a much broader, if not universal context. Thus far SAGA has generated complete spectroscopic coverage within 300 kpc, counting eight Milky Way analogs. The process of choosing ‘analogs’ is detailed and painstakingly recounted in the paper, but the gist of it is that the team looks at a galaxy’s K-band infrared luminosity as a proxy for stellar mass and considers a host of factors related to the galaxy’s halo and its large-scale environment including other nearby galaxies.

Thus far, SAGA has uncovered 25 new satellite galaxies, 14 of which meet the survey’s formal criteria, plus an additional 11 that remain incompletely surveyed. Given that the Sloan Digital Sky Survey had already found 13 satellites among these galaxies, we thus far have 27 satellites around 8 Milky Way analog galaxies that have been subjected to exhaustive analysis.

As to the Milky Way itself, we continue to find what the paper considers ‘faint satellites’ as large-area imaging surveys continue, but the number of bright satellites has remained fixed since the discovery of the Sagittarius dwarf spheroidal galaxy about twenty years ago. Geha and team consider the catalog of bright Milky Way satellites to be largely complete.

The SAGA survey is in its early days, but it is striking that 26 out of the 27 satellite galaxies considered are actively forming stars, unlike both the Milky Way and M31. As the paper notes:

The above results suggest that the satellite population of the Milky Way may not be representative of satellite populations in the larger Universe. Expanding the number of Milky Way analog galaxies with known satellites is required to use these objects as meaningful probes of both cosmology and galaxy formation.

And this is also interesting:

We have characterized complete satellite luminosity functions for 8 Milky Way analog hosts. We find a wide distribution in the number of satellites, from 1 to 9, in the luminosity range for which there are five satellites around the Milky Way. We see no statistically significant correlations between satellite number and host properties, although any correlation would be hard to detect robustly with our small sample size of hosts.

Bear in mind as the SAGA Survey continues that until now, we have based most of our information about satellite galaxies on what we see right here in the Milky Way and in M31. We’re now developing the larger picture that can help us place galaxy formation in context. Finding that even the galaxy we live in is not typical would fit the pattern of recent exoplanet discoveries in suggesting that galaxy as well as planet formation is a deeply stochastic process.

The paper is Geha et al., “The SAGA Survey: I. Satellite Galaxy Populations Around Eight Milky Way Analogs,” accepted at the Astrophysical Journal (preprint).

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A Statistical Look at Exoplanet Atmospheres

Comparative exoplanetology? That’s the striking term that Angelos Tsiaras, lead author of a new paper on exoplanet atmospheres, uses to describe the field today. Kepler’s valuable statistical look at a crowded starfield has given us insights into the sheer range of outcomes around other stars, but we’re already moving into the next phase, studying planetary atmospheres. And as the Tsiaras paper shows, constructing the first atmospheric surveys.

Tsiaras (University College, London) assembled a team of European researchers that examined 30 exoplanets, constructing their spectral profiles and analyzing them to uncover the characteristic signatures of the gases present. The study found atmospheres around 16 ‘hot Jupiters,’ learning that water vapor was present in each of them. Says Tsiaras:

“More than 3,000 exoplanets have been discovered but, so far, we’ve studied their atmospheres largely on an individual, case-by-case basis. Here, we’ve developed tools to assess the significance of atmospheric detections in catalogues of exoplanets. This kind of consistent study is essential for understanding the global population and potential classifications of these foreign worlds.”

Image: An artist’s impression of the kind of systems studied by the UCL team. Credit: Alexaldo.

Presented at the European Planetary Science Congress (EPSC) 2017 in Riga, the study used archival data from the Hubble telescope’s Wide Field Camera 3 (WFC3), finding that most of the detected atmospheres show evidence for clouds, although the two hottest planets, with temperatures exceeding 1700 degrees Celsius, evidently have clear skies at least at high altitudes. Both of the latter show indications of water vapor, titanium oxide and vanadium oxide.

The authors have defined a metric they call the Atmospheric Detectability Index (ADI) to measure the statistical significance of an atmospheric detection, meaning that while we have 16 planets with atmospheres the metric finds significant, other less detectable atmospheres are present in the rest of the sample. The paper explains the 14 spectra without significant atmosphere detection as the result of opaque, high-altitude clouds or low water abundances. It is highly unlikely, in other words, that gas giant planets will fit any no-atmosphere models.

What jumps out of this work is the fact that the detectability of ‘hot Jupiter’ atmospheres through the ADI metric appears to be dependent on planetary radius rather than planetary mass.

“These results,” the paper adds, “indicate that planetary surface gravity is a secondary factor in identifying inflated atmospheres,” though we should also note that the paper identifies an outlying group of five planets with large radii and no detectable atmospheres. The other planets show the correlation between atmosphere and planetary radius. And it turns out that very hot planets produce strong results with this method. From the paper:

Very hot and highly irradiated planets, with atmospheric temperatures above 1800 K feature high ADI atmospheres. Our quantitative retrievals suggest that the cloud top-pressures in these planets are significantly high, meaning clouds are deep in the atmosphere, if present at all…, while retrieved water abundances are constant within the errors… We can conclude that planets with temperatures higher than 1800 K feature clear atmospheres, confirming that most of the element-carriers are present in a gaseous form at such hot temperatures.

We’ll see how the Atmospheric Detectability Index fares as it is applied to future, larger-scale surveys. For we’ll certainly need such surveys as we enter the era of extremely large telescopes on the ground and new missions that will produce huge numbers of new planet detections. The Tsiaras team’s work is important because it shows we are developing the tools and models that will be applied in the future to much larger samples of planetary atmospheres.

The paper is Tsiaras et al., “A population study of hot Jupiter atmospheres,” submitted to the Astrophysical Journal (preprint).

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A Binary Main-Belt Comet

The paper in Nature covering an object known as 288P lays out the case in its title: “A Main Belt Comet.” But what makes this story stand out is the fact that 288P is also a binary.

A team of scientists led by Jessica Agarwal (Max Planck Institute for Solar System Research) discovered when 288P neared perihelion in September of 2016 that it was not one but two objects, asteroids of roughly the same mass and size, in a binary separated by about 100 kilometers. Moreover, they have verified that the small system is not quiescent.

Using the Hubble instrument, Agarwal and colleagues discovered that the increased solar heating due to perihelion was producing sublimation of water ice, in much the same way that the tail of a comet is created. Here’s how the paper describes the process on 288P:

Repeated activity near perihelion is a strong indicator of the sublimation of water ice due to increased solar heating. A model of the motion of the dust under the influence of solar gravity and radiation pressure suggests that the activity began with a brief release of comparatively large (millimetre-sized) grains in July, while from mid-September until at least the end of January 2017 (the last of our observations), the dominant grain size fell to ∼10 µm… This indicates that the developing gas production first lifted a layer of large, loosely connected grains, possibly deposited around the end of the previous period of activity in 2011/12. After their removal and with decreasing heliocentric distance, the gas drag became sufficiently strong to lift also smaller particles.

As a main-belt comet, 288P may give us further insights into how water came to Earth. It is also the first known binary asteroid that can be classified as a main-belt comet.

Image: This set of images from the ESA/NASA Hubble Space Telescope reveals two asteroids with comet-like features orbiting each other. These include a bright halo of material, called a coma, and a long tail of dust. The asteroid pair, called 288P, was observed in September 2016 just before the asteroid made its closest approach to the Sun. These images reveal ongoing activity in the binary system. The apparent movement of the tail is a projection effect due to the relative alignment between the Sun, Earth, and 288P changing between observations. The tail orientation is also affected by a change in the particle size. Initially, the tail was pointing towards the direction where comparatively large dust particles (about 1 millimeter in size) were emitted in late July. However, from 20 September 2016 onwards, the tail began to point in the opposite direction from the Sun where small particles (about 10 microns in size) are blown away from the nucleus by radiation pressure. Credit: NASA, ESA, and J. Agarwal (Max Planck Institute for Solar System Research).

288P’s activity gives us clues to its history. For surface ice cannot survive for billions of years in the main belt. As Agarwal notes, it would have to be protected by several meters of dust mantle, which makes 288P as a binary a relatively recent system, perhaps one that has existed for no more than 5000 years. We then factor in the growing interest in asteroids as delivery vehicles for water to the inner system to see why this system may become something of a benchmark.

Although an impact could have caused the breakup of the original asteroid, the researchers argue in the paper that breakup due to fast rotation is the most likely cause. Later torques caused by sublimation — the breakup would have exposed the ice for subsequent sublimation — could have caused the objects to move further apart:

A decisive factor for the subsequent development of the system is whether the sublimation will last longer than the time required to tidally synchronise the spin and binary orbital periods, which is 5000 years for equal-mass components but orders of magnitude longer for lower mass ratios. Sublimation-driven activity can last longer than 5000 years, such that for high-mass ratio systems it is conceivable that activity prevails after tidal synchronisation. In this case, the recoil force from the local sublimation of water ice can drive binary evolution.

288P is unusual in another way. Asteroid binaries are not uncommon, but most are discovered by radar (when close to Earth) or by analysis of the mutual eclipses revealed in their light curves, assuming a relatively small separation between the two components. Wide binaries like 288P rarely align to produce such eclipses and are too distant to be revealed by radar.

Indeed, it was the evident sublimation of water ice that drew the attention of the researchers. Although a larger sample of wide binaries is needed, Agarwal and team believe the sublimation activity played a decisive role in the evolution of this young binary, affected by the fact that the two components were of nearly equal size, distinguishing 288P from other asteroid pairs.

The paper is Agarwal et al., “A binary main-belt comet,” Naure 549 (21 September 2017), 357–359 (abstract).

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Vintage Voyager: Online Video Resources

With Voyager on my mind because of its recent anniversary, I had been exploring the Internet landscape for archival footage. But Ioannis Kokkinidis made my search unnecessary with the following essay, which links to abundant resources. The author of several Centauri Dreams posts including Agriculture on Other Worlds, Ioannis holds a Master of Science in Agricultural Engineering from the Department of Natural Resources Management and Agricultural Engineering of the Agricultural University of Athens. He went on to obtain a Mastère Spécialisé Systèmes d’informations localisées pour l’aménagement des territoires (SILAT) from AgroParisTech and AgroMontpellier and a PhD in Geospatial and Environmental Analysis from Virginia Tech. Now a resident of Fresno CA, Ioannis tells us in addition how a lifelong interest in space exploration was fed by the Voyager mission and its continuing data return. 

by Ioannis Kokkinidis

Introduction

Back in the end of August 1989, when I was 9 ½ years old and the whole family was on vacation, the Greek press set aside momentarily its coverage of the continuing shenanigans of Greek politics and the rapidly changing situation to the north of our borders due to the collapse of communism and instead put Voyager 2’s encounter with Neptune in its front pages. My late grandfather was an avid reader of newspapers, which I would also read afterwards. I devoured what I could get my hands on, which alas was not much, it was after all August.

The next year my family moved to California for two years, my father was a visiting professor at UCSF, and I read all the books and magazines about space I could find in the public libraries. I even discovered NASA’s Spacelink, a NASA public education computer service hosted by the Marshall Space Flight Center in Alabama, containing mostly NASA press releases, and I would dial in with our PC XT’s 2400 bps modem. However feeding my space interest was a privilege and my parents made me do a thing I truly dreaded in exchange for dialing the long distance number and indulging myself: play the piano.

After we returned to Greece keeping myself appraised of the latest space developments proved difficult since there is very little popular scientific press in Greece and the mainstream press is not that interested in space. When I got our first internet connection NASA’s Spacelink, now a website, was still up, it still had similar content, though more importantly the releases now included in the bottom instructions on how to get on NASA’s press listserv. I promptly signed up, and I still am on that listerv, becoming informed of the latest space developments, especially in an era before the current proliferation of internet space media made it possible to get the latest space news whenever you wish.

Space in general and NASA in particular have been trailblazers in the formation of the current internet media landscape. Early internet users were for the most part technically savvy people with a strong interest in space. When Mars Pathfinder landed in 1997 it became the first major mass internet event with some 200 million hits on its website, at a time when the internet is believed to have had fewer than 500 million internet users worldwide. Space enthusiasts have always had interest that the mainstream media would not quite satisfy and NASA has indulged those interested, posting pictures, press releases and blogs online, up to the point that today the press conferences are open to all and NASA takes questions from the public in social media.

The ability to consume the latest information about space today runs the whole specter, from basic articles intended for children to conference and peer review papers for professionals, which amateurs can also try to parse for meaning. This was not the case though during the planetary phase of the Voyager program. Per the Voyager books and documentaries I have seen over the years the Jet Propulsion Laboratory held a series of daily press conferences during encounter times that apparently were taped, footage of them is shown in said documentaries. Being on the 40th anniversary of the launch of the most successful planetary missions, I wondered if any of that content was available online. I have discovered that quite a bit was, especially of the 1989 Neptune encounter. When I asked online I was also told, and I did discover, that JPL also produced on a daily basis, and at times more often, 10-15 minute Voyager update videos intended for a general public that were apparently broadcast on PBS, in addition to being shown at Planetariums and science centers. I was able to also find several of these videos are available online too. To my surprise very little of this content is uploaded from official NASA accounts, rather it has been uploaded and collected by enthusiasts.

Image: Some documentaries mixed actual footage with artist’s renderings of the landscapes Voyager saw. This image is from a 1982 NASA presentation.

Understanding the origin of the content

NASA does have quite a bit of Voyager data and information up on its website. It still has the original press kits up, which I actually read them back when I dialed up at Spacelink. The scientific information collected is available for all at the Planetary Data System. Voyager has a website up, with a lot of retrospective information. There are several Von Karman lectures up on YouTube, as are press conferences organized both by NASA but also scientific societies such as the AGU. However these mostly date from the last 15 or so years, especially after YouTube was created. The older stuff has been put up by other people. Having watched the stuff and lived a few years both as a child and as an adult I have a few hunches on who is responsible for doing this public service. One needs first to understand how the education system works in the US.

In Greece primary and secondary education is highly centralized. The Ministry of Education in Athens decides what is to be taught in each grade, each class syllabus and even sends the school books and teachers to the public schools. In private schools the owners select their teachers, but the curriculum and books is the same as in public schools. For that matter the graduating exams at the end of the year there are given by public schools teachers to ensure that private schools are not places where bad students go to buy an education certificate. Students and parents have no control over what gets taught up to high school where some choice is introduced, except of course by their vote in the parliamentary elections, or even who teaches it, except by pressuring their local Members of Parliament. Physics teachers – who in Greece are all physicists graduates of four year universities – have no reason to entice students to take their class, the students are obligated to do so. Greeks schools are also seriously lacking in means, before an EU program about a decade ago only about 150 schools out of the 20,000+ that then existed in Greece had a school library, and though with EU funding and school mergers due to the financial crisis some 10-20% of schools now have a library, that is still a small fraction.

The American educational system is far more decentralized but also has more means. The federal Department of Education can set some guidelines and offer grants, but the educational standards are set at the state level. Major decisions such as hiring and school book choices are made at the school district level, with the school district being made up of representatives directly elected locally, rather than ministry of education centrally appointed functionaries. Now down at the school level students have quite a bit of class choice. As a result science teachers need to make their classes appealing to students in order to have them select it. One way to do so is to teach about cool things in class, and space is generally considered very cool. As a result teachers and schools have maintained such cool content like NASA produced educational material. Also American schools have many means not available to Greek schools, such as school libraries that can include a media section with such material. On top of that some 10% or so of American students are home schooled by their parents, and they often use such material to teach science class. Materials on the internet get copied around incessantly so it hard to track who is the original uploader, but after watching quite a bit of the material shown below I am under the impression that most of the videos have been originally taped by some science teacher or librarian, who eventually uploaded them online.

Jupiter encounters

Voyagers 1 and 2 encountered Jupiter back in 1979. Sony’s Betamax was released in 1974, VHS was released in 1977, there are testimonials on the internet of people watching the Voyager Jupiter updates as children every night on TV but if people recorded the updates at the time, they have not put them up, and neither has NASA. What I have been able to find is the following 24 minute video dating from 1982 that talks about the Voyager 1 and 2 encounters at both Jupiter and Saturn. The first 14 minutes are about Jupiter, the rest is about Saturn.

Image: Io’s volcanoes discussed in this 1982 broadcast.

https://www.youtube.com/watch?v=XAFXQ_EeyGs

Saturn encounters

Voyager 1 encountered Saturn in November 1980 and Voyager 2 in August 1981. We do not have online any of the daily press conferences or full Voyager updates; we do have though two educational documentaries from the time that include extended footage from them. In both cases they are of Voyager 2’s encounter with Saturn. Why Voyager 1’s encounter is not shown is unknown to me, but my guess is that these videos where shown in the run up to the 1986 Voyager 2 encounter with Uranus, and thus the idea was to show what Voyager 2 did in its last encounter. Both videos come from collectors of archival documentary footage on YouTube.

NASA Voyager 2 Spacecraft: Encounter with Saturn – 1981 Educational Documentary

https://www.youtube.com/watch?v=OGZk1SOIQaI

Voyager 2 Saturn Encounter as it Happened 1981 NASA Jet Propulsion Laboratory

https://www.youtube.com/watch?v=CJC4s5kijyU

Uranus Encounter

By 1986 video tapes had become more popular. While we do not have footage of any of the press conferences, we have footage of Voyager updates. This video begins in mid update, and then gives several other updates. It seems to have been recorded by somebody in Arizona, since interspaced among the Voyager Updates a small documentary about the USGS Astrogeology center in Flagstaff which is referred to as a local facility. Notice also the scroll for an upcoming Doctor Who episode.

The Voyager Updates do not only deal with the Voyager program, they also give some more general NASA news. One of the updates give a retrospective on how 1977 when the Voyagers were launched Jimmy Carter was just sworn President and the Shah was still ruling Iran. Another updates talks about the upcoming 1986 launches of the Shuttle that will see Galileo, Ulysses and the Hubble Space Telescope get launched. Tragically, Challenger happened two days after Uranus closest approach.

https://www.youtube.com/watch?v=lnijUsIdxSc

Another interesting contemporary program from the time to watch is the Uranus episode of the long running BBC astronomy program The Sky At Night. The BBC has digitized its archive, though the link that YouTube gave me is not from a BBC account:

https://www.youtube.com/watch?v=hUriyE4sGd4

Neptune encounter

The Neptune encounter is far better documented than any of the previous five flybys. Its August timing, which meant that there was very little competing for attention, the experience over the excitement of the previous encounters and the ubiquity of video tapes means that there is quite a bit of material available. The first video is a preview press conference made three months before closest approach, with Ed Stone mostly recapping the previous flybys and explaining to the press new findings since published. In the end he also shows early Neptune pictures taken at the time:

https://www.youtube.com/watch?v=I4io958_BBo

Image: Imagery shown by Ed Stone at the 1989 press conference on Voyager’s encounter with Neptune. Stone used these to explain what would happen in the upcoming encounter.

The following two videos, which appeared as YouTube suggestions after I had seen the rest of the material, purport to contain all the Voyager Updates of the Neptune encounter. They are over twelve hours, so I have only given them a cursory look:

https://www.youtube.com/watch?v=xkUmzPbqJVU

https://www.youtube.com/watch?v=CttozUMkEBA

CSPAN is the American equivalent of Parliament TV. Like Parliament TV it carries educational programs when Congress in not in session. Their oldest video tagged “Space” was a hearing on the Challenger disaster. They do not have Voyage briefings at Jupiter, Saturn or Uranus but they did show most of the Neptune press briefings. They also had an audience Q&A with the director of NASA’s planetary division, William Quaide on August 24, a few hours before Neptune closest approach. Interestingly most of the press conferences are not all the way to the end, CSPAN apparently cut coverage when they went over their allotted time.

August 21 1989 Voyager 2 Update

https://www.c-span.org/video/?8803-1/voyager-2-update

August 22 1989 Voyager 2 Update

https://www.c-span.org/video/?8812-1/voyager-2

August 23 1989 Voyager 2 Update

https://www.c-span.org/video/?8817-1/voyager-2-update

August 24 1989 Voyager 2 Update

https://www.c-span.org/video/?8855-1/voyager-2-update

CSPAN August 24 viewer call in with NASA chief scientist William Quaide on Voyager 2 at Neptune

https://www.c-span.org/video/?8857-1/voyager-ii-neptune

August 25 1989 Voyager 2 Update

https://www.c-span.org/video/?8864-1/voyager-2-flyby-neptune

On the evening of August 24 to August 25 PBS showed a program called “Neptune all Night” where they showed the hourly Voyager updates live and filled the time in between by having a panel in Philadelphia made of the host, a sci fi writer and a NASA scientist. They also had several guests, such as legendary Hollywood sci fi movie producer and several space scientists such as Jill Tarter. On top of that they did take several questions that were dialed in from all over the US. We do not see any of the panelists or guests, between the updates we have the panelists talking while television is showing Voyager animations such as flyovers of satellites or even Space Shuttle astronauts doing things in space. Two people did tape the program beginning at different points. The first video is from a Florida station and it is of middling quality. It is over five hours:

https://www.youtube.com/watch?v=VBR5OUtndg8

The second video is from New York’s PBS 13 and contains far more ads to become a subscriber to PBS than the previous video, or the Arizona PBS Uranus video. The tape is of higher quality, but in begins at the equivalent of the 4h 34 minutes mark from the previous video.

https://www.youtube.com/watch?v=G84w-z6LkDo

The two hour tape ended before the program did, a little after the 3 am Voyager Update. However NASA solar system exploration has put up the last three Voyager Updates of the morning of August 25, for 5 am, 6 am and 7 am in a YouTube video entitled “Voyager 2 at Neptune with Suzy Dodd”. Suzanne Dodd is the current Voyager project manager and she does host the 5 am and 6 am update, though not the 7 am update. At 8 am there was no update, instead Vice President Dan Quayle gave a speech that CSPAN has at its archives in two parts. The Suzy Dodd video is in much better image quality that the rest of the Voyager videos, either at YouTube or CSPAN. Very likely NASA still has the original videos in its archives and at much higher quality than what I found online.

https://www.youtube.com/watch?v=AR_R5mFk9Tc

The Neptune encounter was big enough news that several mainstream media organizations made special reports about it. These YouTube videos do not come from the official station accounts. The first is a CNN special report on the Neptune encounter.

https://www.youtube.com/watch?v=Y11CVuxfvPE

The second special was made by TBS and contains reporting from Japan, which did participate in the Neptune and Triton Voyager occultation. It is hosted by Sidney Poitier and is available in 8 parts. The 8th part contains Chuck Berry playing live three songs at the Planetary Society’s farewell party.

Part 1 of 8

https://www.youtube.com/watch?v=y038-R3kwfw

Part 2 of 8

https://www.youtube.com/watch?v=gKVnzfiw1ac

Part 3 of 8

https://www.youtube.com/watch?v=c8eqYVFgzIU&t=5s

Part 4 of 8

https://www.youtube.com/watch?v=KPVwM7ikI4E

Part 5 of 8

https://www.youtube.com/watch?v=k7e1NDj-v0o

Part 6 of 8

https://www.youtube.com/watch?v=oKfVo_r4q7M

Part 7 of 8

https://www.youtube.com/watch?v=w8Uw1_Rad6Y

Part 8 of 8

https://www.youtube.com/watch?v=2adIOstO51g

Finally Sir Patrick Moore, who most likely was not knighted yet at the time, hosted a Neptune encounter episode for The Sky At Night. This program is far more complete and interesting, in my opinion, than the two other specials.

https://www.youtube.com/watch?v=H9UdqHL6b9Y

The Pale Blue Dot Press Conference

On June 6 1990 Ed Stone and Carl Sagan gave a press conference that for the most part summarized what the Voyagers had found during their planetary mission and revealed to the world the family portrait of the Solar System that Voyager 1 took. It was in this press conference that the famed Pale Blue Dot single pixel image of Earth was revealed. For the first 40 or so minutes Ed Stone gives a retrospective of Voyager, repeating for the most part what he had said a year earlier in the three months before Neptune press conference. He also though gives a few scientific updates on Neptune. After 40 minutes he shows the family portrait of the 6 planets, followed by Carl Sagan talking for 10 minutes on the portrait, followed by 30 minutes of Q&A.

https://www.youtube.com/watch?v=ZQCTgCF8Khk

The videos in retrospective

Over a quarter of a century since the Pale Blue Dot press conference the more interesting part about these videos is what they reveal about the time they were produced. In the Neptune press conferences the Voyager team fielded questions from West German reporters, the Wall after all fell in October 1989 and Germany was reunified in 1990. Carl Sagan proposes that we have a Joint US Soviet program to send people to Mars, the collapse of the Soviet Union was completely unexpected for everyone. Viewers tend to ask the same questions: Why is Voyager 2 not going to Pluto? Why did Voyager 1 not also visit Uranus and Neptune? Why did you choose Triton over Pluto? Did you find any evidence of alien life, preferably intelligent? When are we sending people to Mars? Did you find evidence of a wormhole, like in Star Trek The Motion Picture? Can you talk about the Golden Record?

The Voyager team does promote the next steps: We will use Hubble Space Telescope images, after its upcoming launch, to follow up on Uranus and Neptune. Galileo to Jupiter is about to launch, and we have proposed Cassini and CRAF as follow up, if Congress approves the missions. Magellan was launched 6 months ago, the long launch gap is over, and it was due to the Challenger disaster. With the power of hindsight we can follow up. Magellan has been called Voyager 3 because it followed its engineering. It was very successful but it is alas the most recent American mission to Venus. Galileo was also a successful mission but suffered from being unable to unfurl its High Gain Antenna. Cassini was approved, and its mission just ended. CRAF though, which intended to flyby an asteroid and orbit a comet on which it would throw a projectile was cancelled. Its science goals though were investigated by Stardust, Deep Impact and Rosetta.

Voyager afterwards

The Voyager program did not end with the Solar System family portrait, for that matter it was not even the last images taken by the imaging subsystem. At the time both Voyagers were used as astronomical observatories, targeting stellar sources in the Ultraviolet. A few months later though they rewrote the spacecraft’s operating system and turned off all the instruments except those measuring fields and particles. During the Shoemaker Levy 9 collision NASA considered reactivating the imaging system to take pictures of the event which was not visible from earth. By that time though the imaging team had dispersed and it was hard to reassemble it. In any case Galileo, en route to Jupiter, took better images. From the Jupiter video already it was repeatedly stated that their last target was the edge of the heliosphere. In the Jupiter video Ed Stones expects that to happen by the end of the century, in the Pale Blue Dot conference he expected that in the first decade of the 21st century.

Throughout the 1990s I would read on any updates on the Voyagers sent by the NASA listserv. Most often they were associated with launch anniversaries or lectures at the fall AGU meeting in San Francisco. Both spacecraft did keep on moving outwards into unexplored part of the heliosphere. Voyager 1 crossed the termination shock at 94 AU in December 2004 and Voyager 2 crossed it at 84 AU in August 2007, entering the heliosheath, where the solar wind is subsonic. Where it ended and the Galactic magnetic field started was a point of contention, especially since the plasma spectrometer on Voyager 1, though not Voyager 2, has failed. In 2012 Voyager 1 did see a dramatic increase in external galactic cosmic rays as opposed solar particles, but we were not certain if the spacecraft had crossed into interstellar space because the magnetic field had not changed direction. Eventually though tape playback of the plasma wave instrument data showed that indeed, in 2012, Voyager 1 had crossed the heliopause and was now in the Galactic magnetic field. Voyager 2 has yet to cross the heliopause though that is expected to happen relatively soon.

Image: Voyager moving beyond the Solar System. Credit: NASA.

The Golden Record

It seems that no Voyager article or documentary is complete with talking about the Golden Record and so will I. In all honesty I always found the pictures taken by the Voyagers more interesting than the record. The artifact is intended to be read by aliens who might run into the probes and contains instructions on how to use it. The instructions assume that the aliens are capable of interpreting the visual signs that we have put up sufficiently to decode the contents of the record. This is a very large assumption considering we have no idea what aliens can do and how. For one thing over a century after their discovery, Linear A tablets have never been deciphered. We believe that like Linear B tablets, which are written in Greek, they are accounting ledgers from the Minoan palaces where they were found, but until we read them we cannot be sure. On top of that the Voyager symbols are written in unique characters. The Phaistos Disc is written in a unique script, closest relative of which is the Arkalohori Axe. Wikipedia lists 26 decipherment claims for the Phaistos Disc which remain fanciful since we cannot apply them to another text to see if they make sense there. Michael Ventris’ decipherment of Linear B became accepted after it was used to read tablets that were published after he and John Chadwick published his discovery. Perhaps it would have been better if we had also printed instructions in English.

But say that alien do read the record, which contains both images and sounds coded differently. On top of that the human speech is in 55 languages. Much as Sagan and Druyan did try to give a snapshot of all human civilization, it is very hard to claim that it is an objective view of mankind. None of the contents, either images or songs, deal with war or any other ugly part of humanity. Trying to understand human civilization from the Golden record is like trying to understand Athens of the Classical Era from Pericles’ Funeral Oration: Both are wonderful documents but they portray their world as they wish it to be, rather than what it is. Still though they tell us quite a bit about ourselves and it was a great idea to include the Golden Record on the spacecraft. I sincerely hope that the project to write a repository of Earth Information on New Horizons does happen.

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New Horizons After 2014 MU69

If New Horizons can make its flyby of Kuiper Belt Object MU69 at a scant 3500 kilometers, our imagery and other data should be much enhanced over the alternative 10,000 kilometer distance, one being kept in reserve in case pre-encounter observations indicate a substantial debris field or other problems close to the object. But both trajectories, according to principal investigator Alan Stern, have been moved closer following a ten-week study period, and both are closer than the 12,500 kilometers the spacecraft maintained in its flyby of Pluto.

Image: Artist’s concept of Kuiper Belt object 2014 MU69, which is the next flyby target for NASA’s New Horizons mission. Scientists speculate that the Kuiper Belt object could be a single body (above) with a large chunk taken out of it, or two bodies that are close together or even touching. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Alex Parker.

Stern made the statement in early September at a meeting of the Outer Planets Assessment Group (OPAG), in which he also pointed out that flyby observations of the distant KBO will commence in August of next year in preparation for the early January arrival in 2019. The process of returning acquired data to Earth is estimated to take up to 20 months.

We also get this heartening news: Stern considers the Kuiper Extended Mission of New Horizons to be ‘multi-pronged,’ with the January 1 flyby of MU69 perhaps the prelude to further operations. New Horizons has sufficient fuel and power to operate until roughly 2035, and the downlink of MU69 data will end in September of 2020. The current extended mission was approved for the period 2016-2021. Will there be another?

According to Stern’s presentation at OPAG, the current extension involves not just the flyby of MU69, along with heliospheric plasma, dust, and neutral gas observations in the Kuiper Belt, but also distant observations of up to 30 other KBOs and numerous Centaurs. These studies involve searches for satellites, rings and dust along with examination of KBO light curves and shapes, with numerous papers on these results said to be in early stages of preparation.

With enough power and fuel to make it well into the 2030s, New Horizons, which is after all the only spacecraft with the opportunity to make these observations, could continue its active work for many years. An extended mission from 2021 to 2024 would allow additional KBO flyby search time for future targets as well as continuing Kuiper Belt observations.

And on the question of what happens after New Horizons, Stern’s presentation at OPAG included the possibility of a Pluto orbiter, which is already being studied at SwRI, Ball Aerospace, Lockheed-Martin and NASA GSFC. A tantalizing thought, that.

Jeff Foust quotes Stern in The Space Review as saying this:

“I think New Horizons has a bright future, continuing to do planetary science and other applications. There’s fuel and power onboard the spacecraft to operate it for another 20 years. That’s not going to be a concern even for a third or fourth extended mission.”

Image: Flight controllers (from left) Katie Bechtold, Ed Colwell and Jon Van Eck, working in the mission operations center at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, confirm data indicating that the New Horizons spacecraft had safely exited hibernation on Sept. 11, 2017. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.

Meanwhile, New Horizons ‘awakened’ from a five-month hibernation period on September 11, being brought over the next three days into active mode, in which science instrument checkouts and data collection activities can resume, to be continued until mid-December. From the latest JHU/APL news update outlining the course of the coming months:

The spacecraft will train its instruments on numerous distant KBOs, making long-distance observations with the telescopic Long Range Reconnaissance Imager (LORRI), while also continuously measuring the Kuiper Belt’s radiation, dust, and gas environment. The team also will test the spacecraft’s instruments in preparation for next year’s approach to MU69, and transmit a new suite of fault-protection software – also known as autonomy software – to New Horizons’ computer in early October.

On December 22, New Horizons again goes into hibernation, to be awakened on June 4, 2018, at which point preparations for the MU69 approach will go into high gear. The spacecraft is currently 3.89 astronomical units (AU) from MU69 as Kuiper Belt exploration continues.

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