by Paul Gilster | Nov 20, 2013 | Culture and Society |
Among the numerous groups now emerging with an eye toward space exploration, SpaceGAMBIT has been the one I knew the least about. It was a pleasure, then, to hear from Alex Cureton-Griffiths, who is UK Project Lead for SpaceGAMBIT. Alex was more than happy to offer this description of SpaceGAMBIT and its plans for the future. He tells me he spends his time traveling and talking to people about our future in space and how they can get involved. In his spare time he “hunts for good coffee and hacks on steam-powered satellite thrusters for fun.” Alex, I buy coffee green and roast my own beans. If you’re a coffee guy, we need to talk, man.
by Alex Cureton-Griffiths
When I mention to people that I’m trying to help build humanity into a spacefaring species, I usually get the same reaction: ” I don’t believe it – that’s so cool!”
I’m with them all the way on the second part of that reaction – it really is amazingly cool. It’s the first part that gets me – the “I don’t believe it” part. For so many people, getting to the stars is literally unbelievable. Because it’s assumed to be too difficult, too far off, or too big for individuals to make a difference. People watch movies like Star Trek and imagine we need to have shiny starships to get there, without thinking about the greasemonkeys who build the technology to get us to starships in the first place.
My organisation, SpaceGAMBIT, is a group of those greasemonkeys, and we aim to prove the doubters wrong by getting humanity hacking on hands-on, practical projects that will help us one day live amongst the stars. We’re not alone – we’ve got half a million dollars in funding from the US government to do this, and we’re working with many organisations to Make Things Happen.
How We Make a Difference
Now, it’s no good hammering away on a starship chassis if we don’t even have warp drives yet. Or for that matter, if we don’t even know that warp drives are a possible or optimal technology. Since we’re all about hands-on, just putting together plans and models for interstellar settlement doesn’t really float our boat. Instead, we focus our projects on:
1. Building near-term technologies that will get people thinking about space and settling the stars. Things like a partial space suit and 3D printed planetary rover components
2. Educating and inspiring the public about the need for getting to space and how they can get involved now. These include a range of space badges for Hacker Scouts and workshops for building Cubesats
3. Off-world habitat technologies which also have applications here on earth in disaster relief, developing countries and sustainability. Includes bioreactors and a prototype closed-system underwater habitat
Why focus on the here and now? If the public can’t see a near-term use for space technologies, they go back into “Star Trek” mode. The thing that gets people’s blood pumping is seeing it’s a “real thing” and that they can make a difference.
All of our projects are brought to life by the maker movement through hackerspaces, makerspaces and other community spaces. Basically, an ad hoc worldwide network of passionate, hands-on tinkerers with the tools, community and mindset to Get Stuff Done. Makers aren’t limited by the norms of the engineering industry, so they’re more likely to get something bodged together quickly and rapidly iterate to make it work. And since many don’t have a formal engineering background there’s a lot of out-of-the-box thinking, resulting in off-the-wall designs that might just work anyway.
There are now thousands of such community spaces around the world, including in formerly-wartorn countries like Iraq and Afghanistan, and even NASA is getting in on the act, opening their own makerspace at Ames. And if there’s no space near you, there’s absolutely nothing to stop you getting together with a group of friends and building your own!
Another key point is that all of our projects are open-source, open-hardware, open-documentation, open-everything. Anyone is free to take the projects and replicate, re-use, build on or modify them as they wish. We believe that if we’re to make it as a spacefaring civilization we’ve got to share what we know, not lock it up.
Get Involved
The fantastic thing about the maker community is that anyone can get involved. Hackerspaces and makerspaces are open for anyone to join for a small fee, and no qualifications or background are needed. Whether you’re an engineer, an artist, a kid, or whoever else, you’re free to roll up and start hacking together your own projects. As UK Project Lead for SpaceGAMBIT, I’m a walking, talking case-in-point. I have no formal engineering or space background. In fact, I flunked high school maths and majored in Chinese at university. And here I am, running a space program. If I can get involved, anyone can.
Don’t worry about coding a killer app, knowing how to wire a plug or building a 3D printer from scratch – these spaces are where you can learn from each other, and learning means failing now and again (and celebrating that failure). I was completely clueless on my first day, but over time (and many wonderful failures) I’ve learnt from the other members and developed my skills. Here’s how:
1. Find your local hackerspace. Many big cities have several.
2. Most hackerspaces have an open night or social night. Try to attend one of these to see what it’s really like. Each one has its own vibe, and words can struggle to do them justice!
3. Get involved with a cool project, or just start your own. Instructables has plenty of space projects to get you started off, and we promote many more projects in development through SpaceGAMBIT.org. When it comes to starting your own, you don’t need to ask. Just bring stuff and get working!
4. As soon as you’ve got a project going, you may need funding to continue it: SpaceGAMBIT offers funding for certain types of projects, and there’s always Kickstarter or Indiegogo, both of which have successfully funded space projects.
5. If you have kids (or if you’re a kid yourself), there are lots of great programs out there to get started. Curiosity Hacked (formerly Hacker Scouts) are based in the USA, and Code Club offer after school coding classes around the world.
What’s Next for SpaceGAMBIT?
We’re now working with NASA on the asteroid grand challenge, because we can’t become a starfaring species if we’re wiped out by death rocks from outer space. In a few months, we’ll launch a new round of project solicitation, focusing on how to spot dangerous near-earth-objects and figuring out how to divert them. We’ll also run a couple of competitions to get more people scouring the skies, with the aim of making telescopes cheaper and easier to use.
Like last year, we plan to continue funding projects focused on space and maker education, habitat technologies, and small satellite technologies. For projects we fund, we emphasise rapid iteration and getting things done on a budget. All projects have a funding limit of $20,000, should take 3-4 months to complete and be totally open-source, open hardware and open everything. For now you can check our previous project submission announcement for more information, and get in touch if you have a project you’d like to submit!
by Paul Gilster | Nov 19, 2013 | Outer Solar System |
I don’t usually have much to say about Mars, for this site’s focus is on deep space — the outer Solar System and beyond. But with both the Mangalyaan and MAVEN Mars missions in progress, I’ll take this opportunity to mention new work out of MIT that deals with the effect of Mars on asteroids. The topic is ‘space weathering,’ the result of impacts from high energy particles and more. Richard Binzel and colleague Francesca DeMeo have been looking at disruption to asteroid surfaces, finding that close planetary encounters can explain an unusual fact: The surfaces of most asteroids appear redder than the remnants of asteroids that have crashed as meteorites to Earth.
Back in 2010, Binzel established what he sees as the basic mechanism. Main belt asteroids, orbiting between Mars and Jupiter, are exposed to cosmic radiation that changes the chemical nature of their surfaces. But take an asteroid out of the main belt and give it a close pass by the Earth and ‘asteroid quakes’ will occur, moving surface grains about and exposing fresh surfaces underneath because of the gravitational disruption. Binzel calls these ‘refreshed’ asteroids, and argues that when asteroids of this kind get too close to Earth, they break apart and fall to the surface as meteorites.
How Mars fits into this picture is a bit more of a stretch. At one-tenth the mass of Earth and only one-third its size, Mars seems unlikely to be considered a major gravitational disruptor. But placement is important, for Mars is closely situated to the main belt, which makes asteroid encounters that much more likely to happen. To study the effect, Binzel and DeMeo have tracked asteroids in the database maintained by the International Astronomical Union’s Minor Planet Center, which currently holds data on 300,000 asteroids and their orbits. The researchers’ new paper in Icarus maps orbital intersections between asteroids, Earth and Mars.
Image: Mighty Mars? It’s a small world, but its effect on asteroids passing by it is only now being understood. Credit: NASA.
The duo chose 64 asteroids and calculated the probabilities over the past half million years of close encounters that could have stirred up the asteroid surfaces. The paper focuses on a class of asteroids called Q-type, found primarily among Near-Earth Objects and matching ordinary chondrites spectroscopically over visible to near-infrared wavelengths. Because they are so similar to meteorites, they are assumed to have gone through weathering of the surface regolith, meaning older reddish grains have been churned and replaced. From the preprint:
Ten percent of the Q-types in our sample have not experienced Earth encounter on recent timescales. Thus, the orbited distribution of Q-types suggests Earth encounter is not the only resurfacing mechanism that counteracts the effects of space weathering. These non-Earth encountering objects do cross the orbit of Mars and show low Mars-MOID [Minimum Orbit Intersection Distance] values. We conclude that Mars is likely to play an important role in refreshing NEO surfaces due to its large mass and frequent asteroid encounters.
Two other mechanisms for refreshing an asteroid surface are considered, one being collisions between asteroids in the main belt, the other growing out of the results of the YORP [Yarkovsky, O’Keefe, Radzievskii, Paddack] effect, by which asteroids can be ‘spun up’ by photons streaming outward from the Sun. Binzel and DeMeo’s work found no conclusive evidence that either of these would play a significant role in refreshing asteroid surfaces, although the paper suggests further observations of small main belt asteroids to measure their effect.
So we’re learning more about asteroids even as we discover oddities like P/2013 P5, the unusual object that sprouts six comet-like tails [see What a Strange Asteroid Can Tell Us]. How both their composition and history define their characteristics is going to be an essential study for future efforts to reach and mine asteroids. This MIT news release offers more, including this comment from Vishnu Reddy (Planetary Science Institute), who was not involved in the research:
“On each of the asteroids we have visited so far, every one of them has shown a different kind of space weathering. So it appears that not only is composition an important factor, but also the location of the asteroid with respect to the Sun.”
The paper is DeMeo, “Mars Encounters cause fresh surfaces on some near-Earth asteroids,” Icarus Vol. 227 (1 January 2014), pp. 112-122 (abstract). See also Binzel et al., “Earth encounters as the origin of fresh surfaces on near-Earth asteroids,” Nature 463 (21 January 2010), pp. 331-334 (abstract).
by Paul Gilster | Nov 18, 2013 | Missions |
I often cite Robert Forward’s various statements to the effect that “Travel to the stars is difficult but not impossible.” Forward’s numerous papers drove the point home by examining star travel through the lens of known physics, conceiving of ways that an advanced civilization capable of the engineering could build an interstellar infrastructure. But while Forward was early in this game, so were Iosif S. Shklovskii and Carl Sagan. A Russian astronomer, Shklovskii had written a book’s whose Russian title translates roughly as ‘Universe, Life, Intelligence’ in 1962. Four years later, Sagan would join Shklovskii as co-author and the two would tackle the original book afresh, adding new material that reflected on and expanded the 1962 version’s ideas.
The result was the volume now called Intelligent Life in the Universe. I sometimes recommend books that are essential parts of a deep space library, and this is surely one, significant not only for its historical treatment of starflight but a compelling source of ideas even today. 1966 was early times for the interstellar idea, with the pioneering 1950s papers of Les Shepherd and Eugen Sänger still fresh in the memory; the work of Robert Bussard on ramjets that could move at a high percentage of the speed of light was very much in play. Shklovskii and Sagan thought there were two ways of achieving human interstellar flight, the first of which involved slowing down the human metabolism to allow it to survive long voyages.
Slow Journey, Frozen Time
Automated interstellar probes were still a reach for most scientists in this era, but Shklovskii and Sagan thought that velocities of up to 100,000 kilometers per second — one-third the speed of light — were not beyond reach as our technology advanced. Given that, humans could be frozen for the duration and awakened upon arrival. The challenge was obvious: The density of ice is lower than the density of water, so that freezing a human being, who is composed largely of water, works serious damage to the cells during the freezing and thawing process. Delicate cell structures are disrupted in each case, and anti-freezing chemicals would kill the subject.
Image: The Russian astronomer Iosif S. Shklovskii, whose collaboration with Carl Sagan produced a classic of interstellar studies.
As so often in Intelligent Life in the Universe, Shklovskii and Sagan thought about possibilities that most in the scientific community hadn’t yet considered, particularly Sagan, whose contributions are flagged in the text to make it clear when he is speaking rather than Shklovskii. Sagan had been working with a Swedish biologist named Carl-Göran Hedén, who specialized in microbiology and biotechnology (Hedén would go on to become the founder of the first chair in biotechnology in Sweden, and the first president of the International Organisation for Biotechnology and Bioengineering). Sagan’s conversations with Hedén focused on the difference in density between water and ice, noting that at high pressures different crystal structures and different densities emerge, producing ice that may have applications for human freezing.
Thus a pressure of 3000 atmospheres and a temperature of -40 degrees Celsius turns ordinary ice into ice II, a kind of frozen water that has nearly the same density as the liquid. The conclusion seemed obvious to Sagan, who wrote:
If a human being could be safely brought to and maintained at an ambient pressure of several thousand atmospheres, and then quickly and carefully frozen to very low temperatures, it might be possible to preserve him for long periods of time. This is only one of many possible alternatives. It seems possible that by the time interstellar space vehicles with velocities of 1010 cm sec-1 are available, techniques for long-term preservation of a human crew will also be available.
Sagan thought that with these means, journeys of up to 100,000 years would be possible. A spacecraft moving at 100,000 kilometers per second could reach a star 1000 light years away in 3000 years, with whatever adjustments would be needed for acceleration and deceleration. A trip to the galactic core would take 60,000 years. He went on to say: “If such voyages are to be feasible, the lifetime of our civilization should perhaps exceed the length of the voyage. Otherwise, there will be no one to come home to.” True enough, but it’s hard to imagine coming back to Earth after 60,000 years thinking that the place you returned to would still be ‘home.’
The Relativistic Solution
The second way to make manned interstellar missions happen was, Sagan believed, the use of relativistic spacecraft, which would, because of time dilation, act as a different kind of metabolic inhibitor. This was mind-boggling stuff back in the 1960s, though it followed as a consequence of the by then well established special theory of relativity. Continue to accelerate at 1 g and you reach the nearest stars in a few scant years of ship time. 21 years take you to the galactic center, while 28 years get you all the way to M31, the great galaxy of Andromeda. The ship nudges up ever closer to c, 300,000 kilometers per second, but never reaches it. Poul Anderson explored all this in his wonderful novel Tau Zero, which has blown minds and inspired science careers since it first appeared in Galaxy in 1967.
Shklovskii and Sagan saw such trips as a communications tool. A radio signal would take 2.5 million years to reach Andromeda, and another 2.5 million years would elapse before any possible response. At the time Intelligent Life in the Universe was being written, SETI seemed to solve the intractable propulsion problem by allowing us to ‘explore’ — i.e., to listen — with radio waves that move at the speed of light. Shklovskii and Sagan reversed the paradigm when it came to destinations well beyond the nearest stars. Now it would be actual journeys to these places that allowed a human presence to be known. As Sagan wrote:
…if relativistic interstellar spaceflight were used for such a mission, the crew would arrive at the galaxy in question after perhaps 30 years in transit, able not only to sing the songs of distant Earth, but to provide an opportunity for cosmic discourse with inhabitants of a certainly unique and possibly vanished civilization. Despite the dangers of the passage and the length of the voyage, I have no doubt that qualified crew for such missions could be mustered. Shorter, round-trip journeys to destinations within our Galaxy might prove even more attractive. Not only would the crews voyage to a distant world, but they would return in the distant future of their world, an adventure and a challenge certainly difficult to duplicate.
Surely this passage is the source of the title for Arthur Clarke’s The Songs of Distant Earth, published in 1986, which explores the effects of long-term interstellar flight. Addendum: See Adam Crowl’s comment below — the influence evidently flowed the other way. My mistake.
Given that reaching M31 within the lifetime of a human crew would require a velocity of 0.99999 c, the only solution that fit the bill was Robert Bussard’s interstellar ramjet, which feeds off the interstellar medium to gorge itself with reaction mass, burning a fusion torch aboard a vessel that becomes more efficient the faster it moves. Sagan liked the Bussard concept and thought it violated no physical principles — he even expected it to be achieved in prototype form in no less than a century — but as we’ve seen (see Catalyzed Fusion: Tuning Up the Ramjet), the problems of lighting proton-proton fusion are immense, and so are issues of drag.
Much work would go into demonstrating this in the next few decades, obviously unknown to Shklovskii and Sagan in 1966, but Bussard variants using a catalytic cycle called the CNO bi-cycle (carbon-nitrogen-oxygen) are still intriguing, and as you might imagine, we’re not through with them here on Centauri Dreams. We can take Shklovskii and Sagan as our models. Both had a taste for bold venturing and pushing the limits of possibility, a taste confirmed in their choice of epigram to introduce the book, Pindar’s Six Nemean Ode:
There is one
race of men, one race of gods; both have breath
of life from a single mother. But sundered power
holds us divided, so that the one is nothing, while for the
other the brazen sky is established
their sure citadel forever. Yet we have some likeness in great
intelligence, or strength, to the immortals,
though we know not what the day will bring, what course
after nightfall
destiny has written that we must run to the end.
by Paul Gilster | Nov 15, 2013 | Outer Solar System |
With the Cassini mission continuing through 2017, we’ll doubtless have many fine views of Saturn to come, but the images below merit special attention, enough so that I decided to close the week with them. We’re looking at an annotated, panoramic mosaic made by processing 141 wide-angle images, sweeping across 651,591 kilometers. That covers the planet, its inner ring system and all its rings out to the E ring. Moreover, the view presented here is in natural color, so we see the color as it would be seen by human eyes rather than as distorted during observations at other wavelengths.
You may remember the ‘Wave at Saturn’ campaign from last summer, when the word went out that Cassini would be snapping a view of the Earth from Saturn space. In the mosaic (click the image to zoom in) we can see the Earth as a blue dot to the lower right of Saturn, but Venus is visible too to the upper left, and Mars shows up as the faint red dot above and to the left of Venus. A close look will reveal seven of Saturn’s moons, including the intriguing Enceladus to the left. Enceladus is worth mentioning because the E ring, about 240,000 kilometers from Saturn, is made up of fine icy particles from the erupting geysers in Enceladus’ south polar terrain.
“This mosaic provides a remarkable amount of high-quality data on Saturn’s diffuse rings, revealing all sorts of intriguing structures we are currently trying to understand,” said Matt Hedman, a Cassini participating scientist at the University of Idaho in Moscow. “The E ring in particular shows patterns that likely reflect disturbances from such diverse sources as sunlight and Enceladus’ gravity.”
The second image (below) has been brightened and color-enhanced to tease out the ring structure. Note the blue color of the E ring, which is caused by the diffraction of sunlight. In both images, the Earth, Venus, Mars, Enceladus, Epimetheus and Pandora were brightened by a factor of eight and a half relative to Saturn to make them easier to see, although you’ll still need to zoom in by clicking to make them out. The outer rings (from the G to the E ring) were likewise brightened relative to the already bright main rings. Full background on these images can be found on this JPL page.
Getting a view like this is tricky because trying to see the Earth from Saturn means looking close enough to the Sun to endanger sensitive spacecraft detectors. Thus the need to find a time when the Sun is entirely behind Saturn as seen from Cassini. The spacecraft’s wide-angle and narrow-angle cameras were used to capture 323 images in a little over four hours, with the red, green and blue spectral filters combined to create the natural-color view. Although this is the second time Cassini has viewed it, the Earth has only been imaged from the outer Solar System three times, the first being the famous ‘pale blue dot’ image from Voyager. This is also the first time Earth’s inhabitants were told in advance about a photo that would include their entire world.
by Paul Gilster | Nov 14, 2013 | Asteroid and Comet Deflection |
The Pan-STARRS survey telescope in Hawaii has reminded us how much we still have to learn about asteroids. We saw yesterday that the Chelyabinsk impactor could be studied through physical evidence as well as the ample photographic records made by witnesses on the ground. But P/2013 P5, discovered by Pan-STARRS and then the object of Hubble scrutiny, is in the main belt between Mars and Jupiter, and rather than appearing as a mere point source, the object shows six comet-like tails that have confounded all those who have looked at it.
“It’s hard to believe we’re looking at an asteroid,” said lead investigator David Jewitt, a professor in the UCLA Department of Earth and Space Sciences and the UCLA Department of Physics and Astronomy. “We were dumbfounded when we saw it. Amazingly, its tail structures change dramatically in just 13 days as it belches out dust.”
Image: This NASA Hubble Space Telescope set of images reveals a never-before-seen set of six comet-like tails radiating from a body in the asteroid belt, designated P/2013 P5. The asteroid was discovered as an unusually fuzzy-looking object with the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) survey telescope in Hawaii. The multiple tails were discovered in Hubble images taken on Sept. 10, 2013. When Hubble returned to the asteroid on Sept. 23, the asteroid’s appearance had totally changed. It looked as if the entire structure had swung around. Credit: NASA, ESA, and D. Jewitt (UCLA).
What could cause an object to resemble, as this UCLA news release notes, a rotating lawn sprinkler? Jewitt’s team, which has published its findings in the Nov. 7 issue of the Astrophysical Journal Letters, rules out an impact scenario because that would have caused a sudden release of a large amount of material. The paper notes that the six dust tails have been observed for five months and show no fading over that period.
What’s left? Sublimation of near-surface ice and electrostatic levitation of dust are among the possibilities the paper examines. The most likely solution, though, is an eruptive dust ejection scenario that could have resulted from a high spin rate. The spin could be accounted for by the pressure of sunlight exerting a torque on the 215-meter object. From the preprint:
The surviving hypothesis is that P5 is a body showing rotational mass-shedding, presumably from torques imposed by solar radiation… Rotational re-shaping and breakup under radiation torques are two of the most interesting subjects in asteroid science… Unfortunately, the expected observational signature of a rotationally disrupting body has yet to be quantitatively modeled, making a comparison with P5 difficult. This is, in part, because the appearance is likely to be dominated by small particles that carry most of the cross-section of ejected material while most of the mass resides in large particles which precipitate the instability.
The weak gravity of the asteroid, in other words, could be simply insufficient to hold the rapidly rotating object together, its dust drifting into space to form the tail-like structures we see. Interestingly, the orbit of P5 near the inner edge of the asteroid belt associates it with the Flora family of asteroids, evident collision fragments that follow similar orbits. One recent paper has noted that the spins of other members of this group show evidence for the same kind of radiation torque that P5 exhibits. Ahead for astronomers is follow-up work to learn whether dust leaves the asteroid in its equatorial plane, which would be strong evidence for rotational breakup.
And maybe, as David Jewitt suggests, we’re looking at the main way that small asteroids die. “In astronomy, where you find one, you eventually find a whole bunch more. This is just an amazing object to us, and almost certainly the first of many more to come.”
The paper is Jewitt et al., “The Extraordinary Multi-Tailed Main-Belt Comet P/2013 P5,” Astrophysical Journal Letters Vol. 778, No. 1 (2013), L21 (abstract)
