A KBO Target for New Horizons

What we’ll eventually want is a good name. 2014 MU69 is the current designation for the Kuiper Belt Object now selected as the next destination for New Horizons, one of two identified as possibilities, and the one the New Horizons team itself recommended. Thus we have a target — a billion and a half kilometers beyond Pluto/Charon — for the much anticipated extended mission, but whether that mission will actually occur depends upon NASA review processes that are not yet complete. Still, the logic of putting the spacecraft to future use is hard to miss, as John Grunsfeld, chief of the agency’s Science Mission Directorate, is the first to note:

“Even as the New Horizon’s spacecraft speeds away from Pluto out into the Kuiper Belt, and the data from the exciting encounter with this new world is being streamed back to Earth, we are looking outward to the next destination for this intrepid explorer. While discussions whether to approve this extended mission will take place in the larger context of the planetary science portfolio, we expect it to be much less expensive than the prime mission while still providing new and exciting science.”


Image: Path of NASA’s New Horizons spacecraft toward its next potential target, the Kuiper Belt object 2014 MU69, nicknamed “PT1” (for “Potential Target 1”) by the New Horizons team. Although NASA has selected 2014 MU69 as the target, as part of its normal review process the agency will conduct a detailed assessment before officially approving the mission extension to conduct additional science. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Alex Parker.

We wind up with a situation where action precedes future decision. While the extended mission proposal will not be turned in to NASA until next year, the spacecraft can’t delay its preparations for a rendezvous with 2014 MU69 — trajectory changes factor into the equation. New Horizons, as this JHU/APL news release points out, will perform four maneuvers in late October and early November to make the necessary course changes for a January 1, 2019 flyby.

In anticipation of probable work beyond Pluto/Charon, New Horizons has the necessary hydrazine for a KBO intercept, and we’ll be able to monitor its communications and data return for years to come. Researchers had their eye on the kind of primitive object out of which dwarf planets like Pluto themselves may have been made, and the new target fits the bill.

“2014 MU69 is a great choice because it is just the kind of ancient KBO, formed where it orbits now, that the Decadal Survey desired us to fly by,” said New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute (SwRI) in Boulder, Colorado. “Moreover, this KBO costs less fuel to reach [than other candidate targets], leaving more fuel for the flyby, for ancillary science, and greater fuel reserves to protect against the unforeseen.”

As to that new name, 2014 MU69 is already being called PT1, for ‘potential target 1,’ but will want something a bit more muscular, and certainly more poetic. You’ll recall how tricky it was to find a KBO for this encounter in the first place (see, for example, New Horizons: Potential KBO Targets Identified). Among those found after the search began in 2011, none were within range of the craft’s fuel supply. It took the Hubble Space Telescope to discover, in the summer of 2014, the two prime candidates. And it’s easy to understand Alan Stern’s enthusiasm. 2014 MU69. at about 45 kilometers across, is ten times times bigger than the average comet and a thousand times more massive, even if it’s about 1/10,000th the mass of Pluto.

It wasn’t that long ago — in August of 1992, to be specific — that David Jewitt and Jane Luu discovered the first trans-Neptunian object beyond Pluto/Charon, one that gave rise to the term ‘cubewano,’ named after the latter part of its designation, (15760) 1992 QB1. Jewitt and Luu liked the name ‘Smiley’ for the KBO, but there is already an asteroid with that name (1613 Smiley), so like 2014 MU69, even the first identified KBO could use a new monicker. Whatever we call it, 2014 MU69 should give us a look at the early days of Solar System formation some 4.6 billion years ago, preserved by distance and the outer system deep freeze.


The Prime Directive – A Real World Case

Trying to observe but not harm another civilization can be tricky business, as Michael Michaud explains in the article below. While Star Trek gave us a model for non-interference when new cultures are encountered, even its fictional world was rife with departures from its stated principles. We can see the problem in microcosm in ongoing events in Peru, where a tribal culture coming into contact with its modern counterparts raises deeply ambiguous questions about its intentions. Michaud, author of Contact with Alien Civilizations (Copernicus, 2007), draws on his lengthy career in the U.S. Foreign Service to frame the issue of disruptive cultural encounter.

By Michael A.G. Michaud


Science fiction fans all know of the Prime Directive, usually described as avoiding contact with a less technologically advanced civilization to prevent disruption of that society’s development. In a 1968 Star Trek episode, the directive was explicitly defined: “No identification of self or mission. No interference with the social development of said planet. No references to space or the fact that there are other worlds or civilizations.” Another version of the Prime Directive forbade introducing superior knowledge or technology to a society that is incapable of handling such advantages wisely.

Commentators have pointed out many violations of the directive in the Star Trek series (and in other science fiction programs). The Enterprise crew sometimes intervened to prevent tragedy or promote positive outcomes. De facto, observance of the Prime Directive was scenario-dependent.

Star Fleet personnel sometimes used hidden observation posts or disguises to watch or interact with natives. In one episode, Captain Kirk left behind a team of sociologists to help restore an alien society to a “human form.” At the other extreme, the Prime Directive was interpreted as allowing an alien civilization to die.

Star Trek was not the first source of a prime directive. In Olaf Stapledon’s 1937 novel Star Maker, superior beings take great care to keep their existence hidden from “pre-utopian” primitives so that the less advanced beings will not lose their independence of mind.

A recent article in Science reminds us that the practical application of such a principle in a real contact situation on Earth is riddled with complications and uncertainties. The government of Peru has been debating whether or not to make formal contact with a tribal people living in the Peruvian Amazon, sighted frequently over the past year.

Peruvian policy has been to avoid contact with isolated tribes and to protect them from intruders in their reserves. In practice, this policy has been difficult to enforce. Tour operators sell tickets for “human safaris;” some tribespeople loiter on the river bank, letting themselves be seen. One anthropologist said that they were deliberately seeking to interact with people on the river.

There is a dark side to tribal behavior. Some of the tribals raided a nearby village for supplies, killing two villagers.

The tribespeoples’ conflicting actions have left their desires unclear. Though some have sought goods, shooting arrows at Peruvians suggests that they do not want contact.

Peru’s government wants to train local people to avoid isolated tribes unless those tribes make the first move. The plan is to increase patrols, discourage raids, and make contact with the tribespeople only if they show a willingness for conversation.

This is termed “controlled contact.” Two anthropologists proposed in a Science editorial that “a well-designed contact can be quite safe,” but another group accused them of advocating a dangerous and misleading idea.

One of the proposed explanations for our non-detection of alien intelligences is the Zoo Hypothesis, which claims that more advanced civilizations deliberately avoid making themselves known to us so as not to disturb humankind’s autonomous development. Others suggest practical reasons for such apparently altruistic behavior. As Robert Rood put it, the only thing we could offer them is new ideas. Their intervention would stop our development.

Much of this debate has been driven by guilt over the impact of Western colonial powers on other Earthly societies. Star Trek and other science fiction treatments used interactions with aliens as allegories for our own world.

Some argue that external cultural influences can be positive. What we call Western Civilization was the product of many forces that came from outside. Europe’s major religions came from the Middle East. Others see Westernization as a threat that must be resisted, notably in the Islamic world.

If we ever find ourselves in contact with an alien civilization, one of the parties is likely to be more scientifically and technologically advanced than the other. Will the more powerful intelligences observe some sort of Prime Directive? That may be more complicated than many humans believe.



Andrew Lawler, “Mashco Piro tribe emerges from isolation in Peru,” Science 349 (14 August 2015), 679.

“Prime Directive,” Wikipedia, accessed 21 August 2015.

Michael A.G. Michaud, Contact with Alien Civilizations, Copernicus (Springer), 2007, 237.


Back to the Ice Giants?

As data return from New Horizons continues, we can hope that an encounter with a Kuiper Belt Object is still in its future. But such an encounter will, like the flyby of Pluto/Charon itself, be a fleeting event past an object at huge distance. Our next chance to study a KBO might take place a bit closer in, and perhaps we’ll be able to study it with the same intense focus that Dawn is now giving the dwarf planet Ceres. How about an orbiter around Neptune, whose moon Triton is thought by many to be a KBO captured by the ice giant long ago?

The thought is bubbling around some parts of NASA, and was voiced explicitly by the head of the agency’s planetary science division, Jim Green, at this week’s meeting of a working group devoted to missions to the outer planets. Stephen Clark tackles the story in Uranus, Neptune in NASA’s Sights for a New Robotic Mission, which recounts the basic issues now in play. What comes across more than anything else is the timescale involved in putting together flagship missions, multi-billion dollar efforts on the order of our Cassini Saturn orbiter.


Image: Neptune’s moon Triton, as seen by Voyager 2. Credit: NASA/JPL.

Right now Europa is the more immediate priority when it comes to outer planets work, and for good reason, since NASA has already approved a probe to the Jovian moon. Here we’re talking about 2022 as the earliest possible launch date for a spacecraft that would orbit Jupiter and perform repeated close flybys of Europa, a world we need to study close-up because of the evidence for a liquid water ocean beneath its crust and the possibility of life there. Whether such a probe actually flies as early as 2022 is problematic, and so is the launch vehicle, which in a perfect confluence of events could conceivably be NASA’s powerful Space Launch System.

I say ‘perfect’ confluence because the muscular SLS, if it lives up to expectations, would offer more robust mission options not just for Europa but for all the outer planets. Before any of that happens, of course, we have to build and fly SLS. While issues like that remain fluid, the current investigations into still later missions to Uranus and Neptune would seem to be premature, but they have to be, given not just the scientific but the bureaucratic issues involved. The JPL study on Uranus and Neptune ponders missions that could be launched probably in the 2030s, with the expectation of coming up with a mission design that could be used at both of the ice giants, although cheaper options will also be considered.

In any case, space missions begin with preliminary studies that launch a process feeding into the decadal surveys that set priorities for the next ten years of research. The last such survey, coming out of the National Research Council in 2011, gave particular weight to Mars sample return and the Europa probe. Getting an ice giant mission into the next decadal survey is no sure thing, given a strong case to be made for further investigation of Titan, and Clark notes that Venus is also likely to gain support.

So it’s early days indeed for Uranus and Neptune, but conceptual studies are a critical first step toward eventual approval. It’s daunting, and a bit humbling, to realize that if all goes well — if the bureaucratic gauntlet can be successfully run all the way through myriad technical studies and peer review into the budgeting phase and beyond — any mission to the ice giants will arrive half a century after Voyager 2 made our first and only encounters with these worlds. A return with orbiters would give us the opportunity to evaluate the major differences between the ice giants and the larger gas giants around which we’ve been able to conduct orbital operations.


Image: Voyager 2 image of the crescents of Neptune and Triton taken on its outbound path, about 3 days after closest approach. The picture is a composite of images taken from a distance of almost 5 million km as Voyager 2 flew southward at an angle of 48 degrees to the ecliptic after its encounter with Neptune, the final encounter of its journey through the solar system. Credit: NASA/JPL.

It’s often said that we want missions that can be flown within the lifetime of the people who designed them, which is an understandable though mistaken thought. If you were a planetary scientist, would you turn down the chance to work on a Uranus/Neptune mission design even if you were unlikely to see it arrive? Clark quotes William McKinnon (Washington University, St. Louis) on the ice giant probe concept: “An ice giant mission, presumably an orbiter, is, alas, over the horizon as far as my lifespan is concerned, so I salute those who will live to see it!”

Which is what we do, looking forward to the next generation if we can’t complete a task within our own. On the individual level we can say little about the details of our own mortality, so there is no guarantee of survival to mission completion even for relatively nearby targets. We keep building spacecraft anyway. In the case of the outer system, we take decades to design, approve, build and fly spacecraft not in the name of individual ego but of a shared humanity.

The interstellar effort places this principle in even starker terms, for in terms of the physics we understand today, missions to another star will be a matter of, at best, decades and perhaps centuries of flight time. We can hope that rather than turning away from this effort, we continue to probe it with better designs, continuing missions and a determination to keep exploring.


Sharper Views of Ceres

The mapping of Ceres continues at a brisk pace. The Dawn spacecraft is now operating at 1470 kilometers from the surface, taking eleven days to capture and return images of the entire surface. As this JPL news release points out, each eleven day cycle consists of fourteen orbits, so we’re accumulating views of this formerly faint speck in unprecedented detail. Within the next two months, Dawn will map Ceres — all of Ceres — six times.

Have a look, for example, at this view of one of Ceres’ more intriguing surface features. Taken by Dawn’s framing camera on August 19, the image has a resolution of 140 meters per pixel.


Image: NASA’s Dawn spacecraft spotted this tall, conical mountain on Ceres from a distance of 1,470 kilometers. The mountain, located in the southern hemisphere, stands 6 kilometers high. Its perimeter is sharply defined, with almost no accumulated debris at the base of the brightly streaked slope. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

The naming of surface features also continues, the image below showing a mountain ridge at lower left that’s in the center of Urvara crater. The 163-kilometer Urvara takes its name from an Indian and Iranian deity of plants and fields.


And below we have Gaue crater at the bottom of the frame, named after a Germanic goddess of the harvest.


JPL’s Marc Rayman, chief engineer for Dawn and mission director, notes the continuing success of the mapping operation:

“Dawn is performing flawlessly in this new orbit as it conducts its ambitious exploration. The spacecraft’s view is now three times as sharp as in its previous mapping orbit, revealing exciting new details of this intriguing dwarf planet.”

How to get views as good as Dawn is currently sending without actually making the trip? Rayman points out in his latest Dawn Journal entry that a telescope 217 times the diameter of Hubble could provide the same images, which makes a click on the Ceres image gallery all the more preferable. At its current height, Dawn’s camera sees a square 140 kilometers to the side, which is less than one percent of the almost 2.8 million square kilometer surface of the world.

Ahead for Dawn is a set of six mapping cycles (the images above come from the first of these), with changes in camera angle providing stereo views that will help us understand the topography. As it records infrared and visible spectra of the terrain, Dawn is also returning a radio signal that will help researchers probe the dwarf planet’s gravitational field, a key to the distribution of mass inside the object. At 308 million kilometers from Earth, Dawn’s radio signals take 34 minutes to make the round trip. Remember that all this is being accomplished despite the earlier failure of two of the craft’s reaction wheels, a problem in spacecraft orientation that has been surmounted by ground controllers and will not affect the outcome of the mission.


OSIRIS REx: Asteroid Sample Return

Just over a year from now, we’ll be anticipating the launch of the OSIRIS-REx mission, scheduled to rendezvous with the asteroid Bennu in 2018. This will be the first American mission to sample an asteroid, and it’s interesting to note that the materials scientists hope to return will constitute the largest sample from space since the days of Apollo. As with recent comet studies, asteroid investigations may give us information about the origin of the Solar System, and perhaps tell us something about sources of early water and organic materials. This NASA Goddard animation offers a fine overview of the target and the overall mission.

But OSIRIS-REx is about more than the early Solar System. Recent scare stories have compelled NASA to state that a different asteroid, sometimes identified as 2012 TT5, will not impact our planet in September of this year. As Colin Johnston points out in Astronotes (the blog of Armagh Planetarium), 2012 TT5 will, on the 24th of September of this year, pass within 0.055 AU, or roughly 8.25 million kilometers of the Earth, a rather comfortable miss in anyone’s book. We’re talking about a distance twenty times further than the Moon is from the Earth. [NOTE: I originally mis-stated the kilometer equivalent of 0.055 AU, now fixed thanks to readers who spotted the mistake in the comments].

In other words, this asteroid poses no problem whatsoever when it passes by in September. Let me just quote the NASA news release briefly to get this out of the way:

“There is no scientific basis — not one shred of evidence — that an asteroid or any other celestial object will impact Earth on those dates,” said Paul Chodas, manager of NASA’s Near-Earth Object office at the Jet Propulsion Laboratory in Pasadena, California.

In fact, NASA’s Near-Earth Object Observations Program says there have been no asteroids or comets observed that would impact Earth anytime in the foreseeable future. All known Potentially Hazardous Asteroids have less than a 0.01% chance of impacting Earth in the next 100 years.

The longer-term picture is that assessing asteroids that could be a problem — astronomers call these Potentially Hazardous Asteroids, or PHAs — is an ongoing effort and a wise one. We know that asteroid impacts have had a role to play in the history of our planet, and it would be folly to ignore the potential. Fortunately, the OSIRIS-REx mission plays into that effort, because Bennu is an object with a chance (about 1 in 2500) of impacting the Earth late in the next century. Getting samples here will help us understand how to mitigate any future impact.


Image: An artist’s concept of NASA’s OSIRIS-REx asteroid-sample-return spacecraft arriving at the asteroid Bennu. Credit: NASA’s Goddard Space Flight Center Conceptual Image Lab.

An extremely dark object, Bennu absorbs most incoming sunlight and radiates it away as heat. This brings the so-called Yarkovsky effect into play, gradually changing the orbit of the asteroid over time. Clearly, understanding the asteroid’s trajectory involves anticipating what this tenuous effect can do. Edward Beshore (University of Arizona), who is deputy principal investigator for OSIRIS-REx, explains the mission’s role:

“We’ll get accurate measurements of the Yarkovsky effect on Bennu by precisely tracking OSIRIS-REx as it orbits the asteroid. In addition, the instrument suite the spacecraft is carrying is perfectly suited to measure all the things that contribute to the Yarkovsky effect, such as composition, energy transport through the surface, temperature, and Bennu’s topography. If astronomers someday identify an asteroid that presents a significant impact hazard to Earth, the first step will be to gather more information about that asteroid. Fortunately, the OSIRIS-REx mission will have given us the experience and tools needed to do the job.”

When Bennu was selected as the target in 2008, there were over 7000 known Near-Earth Objects (NEOs), of which fewer than 200 had orbits with the low eccentricity and inclination best suited for the mission. At 492 meters in diameter, Bennu is large enough to offer a stable target for the lander, with a carbon-rich composition believed to include the organic molecules, volatiles and amino acids that could be considered life’s precursors. Of the list of 7000, only 5 NEOs met all these criteria. Bennu was the final pick, and we’ll track OSIRIS-REx’s operations there with great interest. The spacecraft is to arrive at the asteroid in August of 2018.