The PI’s Perspective: Probing Farther in the Kuiper Belt with New Horizons
New Horizons Mission Update
by Alan Stern
Principal Investigator
New Horizons is healthy and performing perfectly as it flies deeper and deeper into the Kuiper Belt! Recently we conducted an engineering review of the spacecraft to “trend” how it was working compared to when it was launched. The result was amazing: Every system and science instrument aboard New Horizons is working as well as it did when we lifted off, more than 14 years and almost 5 billion miles ago. As mission principal investigator I could not be prouder — the men and women who designed, built and tested New Horizons literally created a masterpiece of American workmanship that will likely be able to perform and explore for many more years and many more miles!
Before I update you on mission news, I want to highlight something cool on our mission website, https://pluto.jhuapl.edu/. There’s a crazy amount of detail there for anyone interested in knowing more about the New Horizons mission and our scientific discoveries, but we’ve also posted a file to create 3D spacecraft models. With this file anyone with access to a 3D printer can create their own New Horizons to have at home or at work!
Now for some mission happenings, starting with a cool public engagement project we’re doing this month and next. As I mentioned, New Horizons is almost 5 billion miles from Earth. That is so far away, that the very closest stars appear in different positions in the sky than they do from Earth. This is due to the different perspective New Horizons has of these stars from its far away perch. On April 22 and 23, New Horizons will image two of the closest stars, Proxima Centauri and Wolf 359. Here on Earth, astronomical observatories and amateur observers will simultaneously take images of the same stars. Using software to combine imagery from the spacecraft and the ground, we’ll be able to produce stereo images of these star fields showing each star “popping out” because of the “parallax,” or changed perspective, between Earth and New Horizons.
Nothing like this has ever been accomplished before! We’ll release these 3D images in May, so stay tuned. But in the meantime, details on how you can take part in this experiment are on the mission website.
My first mission news update is that this summer, we’ll be using a trio of the largest telescopes on Earth, specifically, the Japanese Subaru telescope, and the U.S. Gemini and Keck telescopes to discover new Kuiper Belt objects (KBOs) for New Horizons to study. We expect to literally find hundreds of new KBOs! Most of these will be too far to study from New Horizons, but a few dozen will be close enough for the spacecraft to image. Although the objects will just be points of light in the distance, millions or even tens of millions of miles from our spacecraft, New Horizons images will be valuable for studying their surface properties, their satellite systems, their shapes and their rotations in ways that cannot be accomplished from Earth — owing to their great distance and our limited viewing angles from the inner solar system.
New Horizons has been conducting studies of KBOs like this since 2016, but we’ve only been able to find and study about 20 so far. With discoveries from the Gemini, Subaru and Keck telescopes, we hope to triple or even quadruple that number, greatly enhancing our scientific return from the Kuiper Belt.
We will also scour the set of newly discovered KBOs for any that New Horizons might be able to fly by, as we did with the KBO Arrokoth early last year. Computer models indicate the probability of finding another close flyby target is small, because we have so little fuel on board to divert toward such a flyby — but that won’t stop us from looking! Our fondest hope is that we get lucky and have the opportunity for one more close flyby of a KBO. After all, no other spacecraft is exploring (or ever has explored) the Kuiper Belt, and none are on the drawing board to do so. This is humankind’s best chance to get such a close up of another KBO for decades to come!
This 1,000-plus page technical compendium of everything learned about Pluto and its moons by the New Horizons flyby in 2015 will be published late this year or early next.
I also want to update you on another cool development for the mission: We are looking at how to increase the capabilities of New Horizons’ instrument payload through software upgrades. The team is evaluating several cost and capability- increase options for six of the seven instruments, and we expect to decide which ones to implement in May. By about this time next year, these “flight software” changes will be made, tested and sent to New Horizons for us to begin using those new capabilities. Later this year, once we’ve selected which enhancements to implement, I’ll describe each of them.
I’ll close with some scientific news. First, I want to announce the forthcoming publication late this year or early next of a 1,000-plus page technical research volume called The Pluto System After New Horizons. This book, to be published in the distinguished University of Arizona Space Science Series, will contain 24 chapters detailing essentially every aspect of what was learned about Pluto and its moons from the historic first-ever flyby exploration of Pluto, which New Horizons conducted in July 2015. All 24 chapters are now written, each by a team of scientific experts. Some have already completed review by other scientists to improve them, while others are undergoing that step. By May or June, we expect all 24 chapters to be in production for publication. The book should then be published about six months later.
The other science news I want to relay is about a blockbuster discovery this mission made as a result of its close flyby of the Arrokoth. We published the first indications of this discovery in the esteemed research journal Science in 2019; a much deeper analysis confirming the early results was published in Science this February. The discovery is about how Arrokoth, and by inference most other primordial “planetesimals” (or planetary building blocks), came into existence.
For many years, two competing mathematical models of planetesimal formation existed. The data from New Horizons shows, definitely, that only one of these models — variously called the “streaming instability” or “pebble cloud collapse” model — can produce an object like Arrokoth. Our evidence? The detailed shape, geology and alignment of the two halves, or “lobes” of Arrokoth. The New Horizons images, compositional spectra, and color data on Arrokoth all point to this model being how Arrokoth formed. We summarized this discovery in a Feb. 13 press release. This may be the single most impactful discovery of the entire New Horizons mission so far, pointing to how planets got their start while settling what has literally been a decades-long computer modeling duel between competing theories.
And with that big news, I’ll conclude this report. I’ll write again this summer. Meanwhile, I hope you’ll keep on exploring — just as we do!
–Alan Stern
16 responses to “The PI’s Perspective: Probing Farther in the Kuiper Belt with New Horizons”
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Given how rich the discovery payback is from the Kuiper belt, how robust the spacecraft design is, and how cheap high Delta V launch is via Falcon Heavy, we should be launching one of these things every 5 or so years in trajectories that allow multiple Kuiper object flybys. The spectrum of masses out there, and the novelty of the Ultma-Thule object indicates these would be high payback flights. Flying on a totally expendable Falcon Heavy would really bring the transit times down esp if we made use of Jupiter, and Saturn.
I like your idea. Given their alignment with one another, there likely wouldn’t be gravitational assist opportunities involving Jupiter and Saturn every 5 years or so. Given that you could aim for a different part of the Kuiper belt using just Jupiter pretty much any time you wanted. If you hoped to aim for other imaging targets such as Neptune or Uranus along the way to the Kuiper belt, your choice of launch windows will be much more constrained but we have not visited either planet in decades. It would be worth the effort IMO.
Ah, I should have said, making use of Jupiter OR Saturn. Yes, you are correct, and including the other gas giants might be very profitable as well.
Terrific idea. Too bad it’s probably impossible of accomplishment – at least via traditional channels.
One fly in the ointment would be Pu238 availability for the needed RTGs. New Horizons, itself, had to fly with a cut-down RTG that can’t produce enough power to allow all instruments to operate simultaneously owing to shortages at the time of its design and fabrication. The U.S., having stupidly shut down Pu238 production for a number of years, is now in the process of ramping it back up, but the stuff is going to be in seriously short supply for quite awhile yet. So far as I know, all prospective production for at least the next decade or so is already spoken for.
An alternative that might be better in your proposed application anyway, due to a much longer half-life – allowing multi-decadal functional probe lives – is Am241. But this, too, is expensive and in short supply. Getting enough of it for an aggressive program of Kuiper Belt object exploration would certainly involve the necessity of reprocessing major quantities of “spent” commercial power reactor fuel and the political bag of snakes that would be opened up by any attempt to do that would dwarf the howling that met the launch of Cassini back in the day.
There is also, of course, the matter of the Deep Space Network. DSN is finally getting some very-long-needed upgrades, but a much more significant build-up of DSN resources would be needed to deal with a steadily growing skyful of simultaneously transmitting Kuiper Belt probes with useful lives that might exceed a century each.
Doing all the seemingly necessary preliminaries is certainly not outside the laws of physics, but would be significantly financially costly even before the first probe departed Earth and perhaps even more demanding of political, than of financial, capital.
The anti-nuclear hysteria that has prevented the reprocessing of “spent” commercial power reactor fuel for decades is a phenomenon almost entirely of the political left. Most academic scientists, including astronomers, these days also seem to be men and women of the left, given that academic employment of any kind has become almost completely a non-leftists-need-not-apply proposition over the last three or four decades.
That puts any investigator who might, in the abstract, favor a program of the sort you suggest in a difficult position. Stepping up in favor of doing what’s physically necessary to support such a program would subject any academic to instant attention by lynch mobs of his ostensible colleagues in the more innumerate departments of academe.
Best of luck to you or anyone else attempting to gin up such a project as you describe – you’ll need it.
You don’t need Pu-238 powered RTGs if you used a Kilopower reactor using U-235 instead.
An added bonus is that you could have nuclear electric ion propulsion active for most of the flight.
Of course you going need the something like an expendable starship like departure stage on top of a Super Heavy as launcher.for Kuiper a belt probe with a Kilopower reactor.
Not at all. Kilopower is not that large. It’s the reengineering that would be needed. The whole thing is to open a production line with minimal design changes. The Plutonium is a real problem, but the Japanese are a reprocessing power house. I’d hate to outsource it, but between the Japanese and the French it would be more believable. He’s right the US shortfall is steep.
Looked up US production rates. Not up to the task a tall. I’ll see what I can see on Japanese and French reprocessing capabilities. The Japanese used to have a vast reprocessing infrastructure.
Falcon Heavy based outer system missions isn’t going to fly. The Falcon Heavy is only got at best 5 years of availability before retirement. IMO.
There isn’t enough time to set up a outer system mission using a Falcon Heavy. It will have to be with follow on hardware
Whenever Starship flies, it’ll be time to do Kuiper probes they way they really should be. Assembled in orbit with a megawatt class nuclear power source.
Quite likely.
I really am shocked that NASA has not jumped all over Falcon Heavy. It seems the perfect instrument for revolutionizing unmanned space exploration RIGHT NOW.
Yet when I broached this subject with some JPL professionals they not only seemed unaware of the potential benefit, they dismissed the idea. I fear the well entrenched status quo is too used to planning exploration the same way they have for decades, to accept significant change.
Nobody public or private has taken advantage of Falcon Heavy. On a per kg to orbit, nothing is cheaper. Think what that means for the market in general and of course for Starship.
LockMart and the other primes partner with JPL and the university community. They do the congressional lobbying to obtain money for the project and guess what launch vehicle they plan for? There are Falcon predicated proposals coming.
There are Falcon predicated proposals coming.
Are there? I hope so. The only potential one I’ve heard of was the Europa mission.
And here’s the thing, that was my specific question to the JPL people, “Is JPL planning for any future exploration missions, going to exploit the new ten times cheaper launch costs?” The answer I got was, “no”. When I followed up that question, they dismissed the lower prices with a claim that prices had only lowered “at best by only two or three times”. I was shocked by that reaction.
It’s going to matter more in the immediate future. Cuts are coming for everyone and saving those ‘integer’ fractions of budget will matter. Here’s the overarching consideration nobody outside the community puts into consideration. Overhead. Research groups are like little fief princes from the middle ages. They function within a research department, which works under a university. Both the research dept and the university get their cut of the pie. The research institution might use their admin and computing pool to share the work of the project, including things like the guys in the basement machine shop. The university needs cash, right up. Cold hard cash. 50% is a low cut. At places like Caltech, it is as high as 70+ %. Same for corporations like LockMart, they operate in much the same way. What this all boils down to is if a mission is really cheap, the take for the overhead is that much smaller. There are other reasons why satellite design has not changed with the onset of Falcon, but the nature of overhead is another unspoken reason. Lots of challenges at the conceptual level are coming in the coming decades. I think the depression we are probably in is going to help make those changes. It’s going to be very painful.
Is there a 3D pair of this image? NASA used to have pairs. They had one and it looked like a simple round asteroid. I had to change size and I got them side by side and all of a sudden I was looking down the side of a 9 mi long asteroid! What a view! They take a picture, then wait until the spacecraft moves and take another. Stereo.
Sadly the NH stellar parallax project only seems to be targeting 2 stars – and seems to be more of a PR project than attempt to improve on what GAIA is producing. Perhaps the problem is the length of time it will take for NH to transmit a star field image to earth.
If the bandwidth was greater it might be good to get a NH survey of the sky band roughly perpendicular to the earth-NH line.