We’ve just learned that New Horizons is intact and functional, with a ‘phone home’ message at about 1530 UTC that checked off subsystem by subsystem — all nominal — amidst snatches of applause at the Johns Hopkins Applied Physics Laboratory. The solid state recorders (SSR) are full, with pointers indicating that flyby information is there for the sending, even as the spacecraft continues with outbound science. New Horizons will pass behind the Sun in early January, giving us a break in communications for a few days this weekend. Over the next 20 months we will get the entire package from Ultima Thule. Patience will be in order.
Here’s the approach image that was released yesterday.
Image: Just over 24 hours before its closest approach to Kuiper Belt object Ultima Thule, the New Horizons spacecraft has sent back the first images that begin to reveal Ultima’s shape. The original images have a pixel size of 10 kilometers (6 miles), not much smaller than Ultima’s estimated size of 30 kilometers (20 miles), so Ultima is only about 3 pixels across (left panel). However, image-sharpening techniques combining multiple images show that it is elongated, perhaps twice as long as it is wide (right panel). This shape roughly matches the outline of Ultima’s shadow that was seen in observations of the object passing in front of a star made from Argentina in 2017 and Senegal in 2018. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.
And here’s the best approach image, released a few minutes ago at the press briefing.
The bi-lobate structure is obvious, but is it a single object or two in tight orbit of each other? We should have the answer to that question in an image that will be released tomorrow. Project scientist Hal Weaver displayed the slide below showing the shape and spin of Ultima. The lack of lightcurve is explained by New Horizons approaching along the line of polar rotation.
Some background thoughts:
Ultima Thule has pushed New Horizons to its limits. Mission principal investigator Alan Stern put it best at yesterday’s mid-afternoon news conference when he noted “We are straining at the capabilities of this spacecraft. There are no second chances for New Horizons.”
If the primary mission had been the long-studied flyby of Pluto/Charon, whose orbit had the benefit of decades of analysis, Ultima Thule presented controllers with an object not known until 2014, when it was discovered as part of the deliberate hunt for a Kuiper Belt object within range. Thus much about the orbit was unknown, making for what Stern described as a ‘tough intercept.’ Factor in the increased distance from the Sun far beyond Pluto and its effects on lighting conditions, as well as a power generator now producing less wattage because of its age.
Fortunately, LORRI, the Long Range Reconnaissance Imager, had spotted Ultima as far back as August 16 and the spacecraft had been imaging the object ever since, using long exposure times and co-adding procedures in which multiple optical navigation images are layered over each other, until in the last month of the approach the motion of the target could be seen, as mission project manager Helene Winters showed graphically at the same news event. Hazards like moons and rings were ruled out and the optimal trajectory, with approach to within 3500 kilometers, was available. If all went well, the early imagery will give way to fine detail.
1.6 billion kilometers beyond Pluto, New Horizons needed to hit a 40 square mile box with a timing window of 80 seconds, an epic feat of navigation that will surely wind up discussed in the next edition of David Grinspoon and Alan Stern’s book Chasing New Horizons (Picador, 2018), unless the duo decide to spin Kuiper object exploration into a book of its own. But I think not. New Horizons’ story should be seen whole, a continuing story pushed to its limits and, like the Voyagers that preceded it to system’s edge, still returning priceless data.
Congratulations to the New Horizons team and the New Frontiers programme too. Couldn’t have more apt names.
It looks like a peanut to me (unless it actually is two objects in close rotation around each other). Is it going to appear much darker in higher resolution pictures? There was a lot of talk about its low albedo and that it might have a dark surface containing carbon compounds.
On your last sentence Paul, “New Horizons’ story should be seen whole, a continuing story pushed to its limits and, like the Voyagers that preceded it to system’s edge, still returning priceless data”, for how long might it be possible to still be harvesting data from this probe? Can we dare hope to see a member of the Oort Cloud from NT someday?
If only we could keep the power running! No, I’m afraid we’ll see no Oort object from New Horizons. It will indeed get to the edge of the inner Oort, but the estimates I’ve seen for that are in the 500 year range. And the max for the craft’s radioisotope thermoelectric generator takes us to maybe the late 2030s.
I think more praise should be given to IOTA, the International Occultation Timing Association, founded by David Dunham, which is a worldwide amateur grouping dedicated to the practice of obtaining accurate timings of occultations of stars by asteroids, planets, planetary moons, and our Moon. IOTA helped greatly with the organization of the occultation observations of Ultima Thule in Chile and Argentina and South Africa, which have proved so very helpful for the success of this flyby.
Agreed. And let’s all remember how accurate the occultation information has turned out to be! Extremely useful data.
I want somebody with the right qualifications to propose David Dunham for the Nobel Peace Prize (and I told him so to his face in 2014). In my opinion, the development of the international occultation timing group shows notable similarities to the development of amateur radio a century ago. Both are completely non-commercial activities, purely driven by hobbyist interest, and both have absolutely no potential to do any harm to anybody, ever; they can only do good. In the case of amateur radio, no one man could really be given the credit, but in this case, David Dunham is THE MAN. He should be recognized while there is still time.
Now here I plead confusion; at the distance that this object was from earth when the encounter occurred as I understand it from the previous entry into Centauri dreams that the spacecraft was approximately 12 light hours distance. Now I’m using approximate numbers and all that, but if the encounter occurred at 533 UTC and you get back info at 1530 UTC, then that’s a approximately a 10 hour difference. Not following here.
Now this is been an extremely exciting encounter to me even more so than Pluto, because it was not only a first, but it was off-the-cuff, so to speak in its planning. Does anyone know at this relatively early stage whether there has been any consideration as to much planning into crafts that would be dedicated to looking at these outer solar system planetoids?
New Horizons is roughly six light hours out, so the round trip is twelve. When data is returned partially depends on the mission plan; it’s not an immediate return of data.
Awesome science and engineering! A 40 square mile box! That works out to the rough equivalent of one millimeter precision over the distance between Washington D.C. and New York City.
I am willing to bet that Ultima Thule bears a resemblance to this comet:
Or Comet Borrelly:
Or a bit of both.
Right. Makes me think that this peanut-like, contact binary shape must be quite common in the outer solar system. Perhaps they form as two bodies orbiting nearby with nearly no realative speed difference. The weak gravitational attraction pulls them together and they stick. Gradually they accumulate material that fills in the gaps in the neck reagion between the two lobes. They slowly grow like snowballs tumbling in space.
This makes me wonder if the surface of UT will prove to be as old as has been advertised. The material on the surface may have formed 4.5 BYA, but it could have been deposited on the surface more recently, and over a long period.
NH PI Alan Stern on doing their version of the Pale Blue Dot:
Question: “Can @NASANewHorizons reproduce the famous “Pale Blue dot” image? @AlanStern: Yes we think we can but there is a risk of burning the cameras out – permanently – so we would want to do all flybys first. #UltimaThule
2:38 PM – Dec 31, 2018
Another project that is going to have to wait until NH is done doing all its science is this:
Any news on this project? Even if it succeeds, any future recipients will have to be able to read the information off a software and hardware storage technology from circa 2000. Think of how hard it is to read data off of tape reels and floppy disks from just a few decades ago.