15 ms·

New Horizons’ first hi-res imagery of Ultima Thule

697 points by mbrundle 8y ago

mbrundle 8y ago
I find it truly amazing that New Horizons was able to take photos of a 20 mile object whilst flying past at ~8 miles/sec - that’s an incredibly small space and time window within which to capture the images. Does anyone know how NASA manages to pilot spacecraft with this level of precision? What kind of engineering processes do you need to enable this?
- deleted 8y ago
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- jameskilton 8y ago
  Actually doing the fly-by is less impressive (the fly-by was planned and programmed a while ago) than the fact that we were able to line up Horizons to an object like this at all! https://twitter.com/Alex_Parker/status/1077986070128668674 https://twitter.com/Alex_Parker/status/1077986070128668674
  - weavie 8y ago
    I find it more impressive and awe inspiring that stuff in space is so predictable that we can actually program the fly by such a long time in advance and get such a high degree of accuracy.
    - dnautics 8y ago
      have you ever done course corrections in KSP? A tiny nudge early on is enough to make a huge difference farther out!
      - TeMPOraL 8y ago
        Yup. And if you've ever done maneuvers manually in KSP, you know that a tiny error in your nudge early on - e.g. hamfisting the throttle, or being a little too late in mid-maneuver staging - leads to a huge difference farther out, which you then have to correct, wasting precious ∆v :). I'm very much impressed by the control precision of real-life space probes.
        dnautics 8y ago
        ah yes, you are commenting on the precision not on the magnitude of the displacement!
        brianpgordon 8y ago
        Check out the crazy journey Rosetta took on the way to 67P/Churyumov–Gerasimenko: https://commons.wikimedia.org/wiki/File:Animation_of_Rosetta_trajectory.gif https://commons.wikimedia.org/wiki/File:Animation_of_Rosetta...
        theon144 8y ago
        Wow, I actually had no idea; how is this all pre-planned, does somebody at NASA just put "67-P/Churyumov" into a "Orbital Maneuver Planner" and let some computers crunch the possible paths out? Or does someone actually sit down and come up with the possible sequence of orbital assits (to later verify with a computer) with a pencil and paper?
        ironcan 8y ago
        Just a correction, but it's a project of the European Space Agency, not NASA.
        lokedhs 8y ago
        It's a combination of both. They have tools that help worth the trajectory calculations, but they have to manually decide on the basic layout of the path to take. There is a very interesting interview with Pablo Munoz from the Bepi Colombo team about flight dynamics on the Omega Tau podcast that explains this: http://omegataupodcast.net/295-bepicolombo/ http://omegataupodcast.net/295-bepicolombo/ The other interviews on the same episode are also worth listening to. In fact, the entire podcast is great.
      - joaomacp 8y ago
        I think everyone with an interest in spaceflight should play Kerbal Space Program. It gives you a sense of scale, both of space and time (luckily you can fast-forward to 100.000x), and also teaches you the basics of making orbital trajectories and correcting them, landing on planets/moons with different gravity... I'm really glad to have played it!
    - aurailious 8y ago
      My understanding was that the exact position was known within a few hundred miles of precision using both Hubble and the NH's cameras.
    - kamaal 8y ago
      Even more so given that how do you navigate these things in space, I mean its position. Given how large space is, and there is no map etc. It's just insane. I guess every press of button needs to be planned years in advance.
    - mpweiher 8y ago
      I also find this somewhere between impressive and amazing. However... ...after watching the Dragon/ISS docking manoeuvre for quite a bit longer than I probably should have, I think I now understand this precision better. When we think of "flying" including flying in space, we automatically have an image of something that's a bit unstable, always being buffeted a little, because that's how all the flying we are familiar with is. Actually seeing that docking manoeuvre, you get a feel for just how stable things are in space. When the Dragon is parked in its relative position (10m?) it is just there, rock solid, as if attached with steel beams. No, better, as if both parts are part of a single piece of granite. No quivering, nothing. Of course this is intellectually clear/obvious, but seeing it in practice is something different. https://www.youtube.com/watch?v=ysyK-J0tkEk https://www.youtube.com/watch?v=ysyK-J0tkEk
- hcrisp 8y ago
  I searched for "New Horizons GNC" and this link came up [1]. "The AOCS/GNC (Attitude and Orbital Control System / Guidance Navigation and Control) subsystem takes care that a spacecraft points to a specific point in space, determines the s/c attitude, and does trajectory corrections." [1] https://space.stackexchange.com/questions/9556/how-does-new-horizons-control-its-attitude https://space.stackexchange.com/questions/9556/how-does-new-...
- ilkkao 8y ago
  In the press conference they said that the spacecraft tried to take one megapixel image of Ultima Thule one hour after this image. Interesting to see it in couple months.
  - tabtab 8y ago
    It will be a giant blurry thumb, just like my vacation photos. Except maybe green and glowing this time.
- gibolt 8y ago
  For a more detailed summary of the amazing collaborations necessary and challenges faced, Scott Manley: https://youtu.be/ymJRlUQfPfQ https://youtu.be/ymJRlUQfPfQ
  - macleginn 8y ago
    They actually managed to predict the bi-lobed shape by keeping track of when the shadow of the object swept different points on the Earth’s surface. Amazing.
    - scrumbledober 8y ago
      I watched that video and when the pictures finally came out i was completely floored by how accurately they were able to predict the shape. An incredible problem solving strategy that seems very simple in hindsight.
- dekhn 8y ago
  the development of double precision floating point, and the kalman algorithm, were two major improvements. Basically there is a computer at JPL that, given a location in the solar system and a current location of a ship, will give you instructions on when to burn. After you burn fuel to move, you update based on visual locations of known stars, fit a model, and do incremental burns until convergence. The book Digital Apollo touches on a wide range of issues associated with building systems that can do this.
  - karmakaze 8y ago
    > the development of double precision floating point So refreshing to hear that a double is good enough for JPL when repeatedly told it's not good enough for mere dollars and cents.
    - perl4ever 8y ago
      New Horizons is a mere few billion miles/km away, while financial matters these days sometimes involve trillions. Plus extra digits for cents and fractions thereof, of course. “There are 10^11 stars in the galaxy. That used to be a huge number. But it’s only a hundred billion. It’s less than the national deficit! We used to call them astronomical numbers. Now we should call them economical numbers.” - Richard Feynman
      - dekhn 8y ago
        i know you're joking but it's really the precision at large numbers that makes doubles so valuable. Typically when somebody is steering a spacecraft to a remote location, the large distance as well as the fine precision needs to be represented. I am not aware of people working with very large sums of money who also need penny-level precision (and even then, floats aren't the right solution).
    - planteen 8y ago
      JPL also has PhD applied mathematicians on staff to ensure numerical stability of their algorithms at double precision. Most developers do not have the ability to do that sort of non-trivial analysis. They are not just blindly saying "a double is good enough."
- lisper 8y ago
  > photos of a 20 mile object whilst flying past at ~8 miles/sec Not to detract at all from the astonishing technical achievement, but that's the wrong comparison. You can see the ISS with your naked eye, and it's a <1 mile object flying past at 4.8 miles/sec. The right comparison is with the distance at which this photo was taken: 18,000 miles, or about half an hour from closest approach. Actually, the right comparison is of the closest approach distance (~2000 miles) with the distance from earth (4,000,000,000 miles). That's like launching a missile from Los Angeles to New York and hitting your target to within a meter.
  - jdmichal 8y ago
    To be fair, while that's an accurate representation of the distances, it's not accurate of the difficulty. They don't have to deal with unpredictable atmosphere. There's reasons laser-guided missiles are about 1-2 meters-ish of accuracy with constant guidance, while we can basically fire-and-forget spacecraft to 4 billion miles away.
    - Retric 8y ago
      Spacecraft also do some corse corrections. You can also measure where your going very accurately averaging over a few hours.
    - dwaltrip 8y ago
      They do have to deal with accurately determining the target destination, especially so in this case.
    - lisper 8y ago
      No, that's actually not true. Hitting Ultima-Thule is much harder. For starters, just figuring out where U-T actually is is very difficult. The observations we have only constrain two of its three degrees of orbital freedom. The third has to be inferred via orbital mechanics. Likewise, figuring out where the spacecraft is is also non-trivial. By way of contrast, figuring out where you are relative to New York to within a meter of accuracy is, nowadays, a simple matter of switching on your GPS receiver. (Even without GPS, all you need is inertial guidance that is stable for half an hour or so. That's much easier to achieve.) Finally, there are unpredictable orbital disturbances. N-H uses thrusters for attitude control, whose effect on the trajectory is not entirely predictable. (c.f. https://en.wikipedia.org/wiki/Pioneer_anomaly https://en.wikipedia.org/wiki/Pioneer_anomaly, which was only detectable because, although Pioneer had thrusters, they were turned off for long periods of time). I know these things because I used to work at JPL. There are entire teams dedicated to spacecraft navigation. The stuff they do will blow your mind.
- tabtab 8y ago
  Re: able to take photos of a 20 mile object whilst flying past at ~8 miles/sec...Does anyone know how NASA manages to pilot spacecraft with this level of precision? I cannot speak for this probe, but other probes have made the probe itself or camera boom move slightly to compensate for the target moving relative to the probe. It's kind of like moving your head back and forth to follow a tennis match if your eyes alone have difficulty tracking. The object looks like BB-8. We'll get even better pics in the coming weeks.
- ohiovr 8y ago
  Not to mention seeing it in practically pitch black darkness
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jimijazz 8y ago
This is why I love HN: because I can count to have updated links to content I care for.
- HenryBemis 8y ago
  And I logged in a few mins ago just to post this, but I am happy to see the community is like-minded!!
- scrumbledober 8y ago
  I've been getting most of my updates for this from /r/space personally, but I think that's the main attraction of HN for me. I don't need to curate my own list of subreddits to get links to content that interests me, because it's all (mostly) likeminded people on here that are on average interested by the same kind of stuff as me. I find more new interests on here than I ever could on reddit looking through my preconceived list of interests.
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deeths 8y ago
Here's a link to the press conference slides: http://pluto.jhuapl.edu/News-Center/Press-Conferences/index.php?page=2019-01-02 http://pluto.jhuapl.edu/News-Center/Press-Conferences/index....
skunkworker 8y ago
That is amazing. It reminds me of a snowman or two snowballs frozen together, except it's red not white. As seen in the combined image. http://pluto.jhuapl.edu/Galleries/Featured-Images/pics800wide/MU69_image_v1%20copy.png http://pluto.jhuapl.edu/Galleries/Featured-Images/pics800wid...
- kylek 8y ago
  Reminded me of 67p (albeit that is slightly more rubber-ducky shaped) https://en.wikipedia.org/wiki/67P/Churyumov%E2%80%93Gerasimenko https://en.wikipedia.org/wiki/67P/Churyumov%E2%80%93Gerasime...
- compsciphd 8y ago
  my caption to the article that I posted to facebook was "do you wanna build a snowman", so I guess thinking along the same lines :)
- stcredzero 8y ago
  It reminds me of a snowman or two snowballs frozen together, except it's red not white. The 21st century world of asteroid and Kuiper belt colonization is going to be far fluffier and squishier than we thought it would be in 80's Sci-fi!
- rhizome 8y ago
  Comet 67P has a similar shape. I have to wonder if there's something inherent in these flying rocks that causes them to take a dumbbell shape.
  - antonvs 8y ago
    The inherent factor is collision, which is what forms most objects like this.
- TeMPOraL 8y ago
  Huh, given the color photo, it reminded me of a potato. Yes, I really did find a potato looking like this once.
jacquesm 8y ago
Absolutely amazing that they nailed the shape so well based on the occlusion data. That is super impressive.
- tomerico 8y ago
  From /r/space: Image of the occultation profile vs actual shape: https://i.imgur.com/PNh4nmX.png https://i.imgur.com/PNh4nmX.png Each line is the same star viewed from a different point on Earth. They arranged for telescopes in a long line North to South to all observe UT at the same time, just as it was predicted to pass in front of the star. Then they precisely timed the apparent blinks of the star. The North-South offset meant the star bisected UT across different sections for each telescope. Then they just worked out the parallax difference and mapped out the blink times on a chart to see the silhouette.
  - 6nf 8y ago
    From that pic it looks like they were able to measure accurately to within meters of the actual shape at this distance! That is incredible
    - jcims 8y ago
      Those streaks in that pic are the path of a star that UT passed. Given they know the velocity, if they time the period where the light from the star is occluded, they get a measure of how wide the object is at that elevation. This is what an occultation looks like: https://www.youtube.com/watch?v=7Y_qc8Ifhso https://www.youtube.com/watch?v=7Y_qc8Ifhso Crazy they are able to map a few of those together so precisely to get this data.
quakeguy 8y ago
"The team says that the two spheres likely joined as early as 99 percent of the way back to the formation of the solar system, colliding no faster than two cars in a fender-bender." Welded together by gravity, i'm really in awe seeing the, by far, weakest power so lovely at work.
- robotrout 8y ago
  So, two masses were close enough in relative velocity and vector, that one of them didn't careen off the other one, and instead, allowed the weakest of all known forces to bond them together as they hurtled at high velocity through space. This object(s) seem statistically unlikely to me. I'm not saying it's artificial. That would be even more unlikely, by orders of magnitude. Just saying "Wow!".
  - hughes 8y ago
    As this is the first Kuiper Belt Object we've visited, it's hard to draw much about the statistics of the thing.
    - robotrout 8y ago
      If they're all like this one, that would be puzzling indeed! Well done Mr. Spock!
    - tempestn 8y ago
      What's exciting to me is, both the first interstellar object we've observed visiting our solar system (Oumuamua) and the first Kuiper Belt Object we've visited have been "unusual". That strongly suggests to me that the unusual is more usual than we would have suspected, which means there's probably a great deal of opportunity to increase our understanding of the universe!
      - hyperpallium 8y ago
        It's easier to observe bigger objects than smaller objects. Bigger objects have greater gravity than smaller objects, therefore are more spheroid. As we get better at observing, we'll see more objects that are less spheroid.
samstave 8y ago
I personally find it amusing and interesting that the physical object, Ultima Thule, looks similar to the Virtual Game logo "Ultima" https://upload.wikimedia.org/wikipedia/en/6/6a/Ultima_Online_-_The_Second_Age_Coverart.png https://upload.wikimedia.org/wikipedia/en/6/6a/Ultima_Online...
- wallace_f 8y ago
  The nostalgia and innocence and discovry of childhood hit me so hard when I saw that logo
  - tunnuz 8y ago
    I feel you.
  - mhh__ 8y ago
    Quite interested as to by whom/why this was downvoted
    - CamperBob2 8y ago
      Forget it, Jake, it's HN
high_derivative 8y ago
Whenever I see these updates, I am reminded of the three body problem trilogy and its contemplations on space exploration (the parts I enjoyed the most). Then I get sad because things just take so incredibly long on a stellar scale, and a human life is so short.
ilamont 8y ago
The new images — taken from as close as 17,000 miles (27,000 kilometers) on approach — revealed Ultima Thule as a "contact binary," consisting of two connected spheres. Are these common in the asteroid belt or as smaller moons of the outer planets?
- InclinedPlane 8y ago
  As far as we can tell, they are pretty common. But we haven't visited enough objects to have firm statistics.
sizzzzlerz 8y ago
Pretty decent resolution of a object 27000 km distant. Has anybody seen the specs on what type of lens NH uses for images like this?
- ihattendorf 8y ago
  It's an 8" Ritchey–Chrétien telescope with a 1024x1024 pixel CCD camera. http://pluto.jhuapl.edu/soc/lorri_about.html http://pluto.jhuapl.edu/soc/lorri_about.html
- azernik 8y ago
  This is still nowhere near full resolution - it's at 140 meters per pixel, whereas the camera got 30 meters per pixel. It's going to take a few days to download the full images at 1kbps though.
  - Avamander 8y ago
    Isn't it 1000baud than 1kbps?
    - Tor3 8y ago
      No, "baud" counts number of signal changes per second, which would equal number of bits per second in the old past (one bit encoded by one signal change). Ever since modems changed to e.g. quadrature encoding the number of bits per second would be higher than the baudrate. When somebody talks about bitrate these days then bps (bits per second) is what they should be using, not baud.
ajuc 8y ago
We only have 2 examples, but both this and the Rosetta mission object were rubber-duck-shaped. Is this very common?
- peter303 8y ago
  14 missions to comets, 20 to asteroids, and around 50 planetary small moons imaged well enough to see their shapes. Under a hundred miles in diameter many have irregular shapes. I would guess this shape only occurs a few percent of the time. Wednesdays news conference speculated UT shape is primordial, while the others may have been carved through four billion years of planetary evolution.
- InclinedPlane 8y ago
  It's pretty common. Based on radar data about 10-15% of Near Earth asteroids (larger than 200 meters) are contact binaries (or contact-binary shaped at least). We don't have enough data on main belt asteroids, trojan asteroids, and especially TNOs/KBOs to say what the percentages look like for those populations but it's a fair likelihood that the proportions are at least as high if not higher among KBOs.
azernik 8y ago
"hi-res" is relative - this is still about 5 times the feature size that was actually captured by the LORRI camera. Going to have to wait at least a few days for the glorious 30m/pixel version.
- Avamander 8y ago
  Some page wrote that it takes more than a year to get every piece of information about the fly-by.
  - SubMachineGhost 8y ago
    Pluto's flyby generated about 8GB of data and it took about 16 months to get all of it downloaded [1], and this data includes more than just the images, and i read somewhere that the Ultima Thule flyby will generate about 6GB of data. I think the images are the first thing that get downloaded, so it should not take more than a week to get all high res images. 1 - https://en.wikipedia.org/wiki/New_Horizons#Telecommunications_and_data_handling https://en.wikipedia.org/wiki/New_Horizons#Telecommunication...
  - azernik 8y ago
    20 months, actually.
- hyperpallium 8y ago
  It's hi-res for a playstation 1. substantive content: new horizons uses a modified MIPS R3000 CPU (ok, not the PSX's GPU, and not used for everything on NH, but) https://www.theverge.com/2015/1/15/7551365/playstation-cpu-powers-new-horizons-pluto-probe https://www.theverge.com/2015/1/15/7551365/playstation-cpu-p...
entity345 8y ago
Fantastic. Just one thing: it would be great if NASA dropped imperial units as main units in such articles.
- herewulf 8y ago
  I agree. However, the people that are paying for this mission still use imperial units. Those of them that are paying the most attention would probably agree with us though.
  - perl4ever 8y ago
    US customary units are not imperial units. Many people don't realize, for instance, that MPG is not comparable between the US and the UK because gallons are substantially different.
- perl4ever 8y ago
  I don't think they use imperial units.
- ars 8y ago
  Why? What difference does it make? It's just a unit. It makes exactly 0 difference.
- dev_north_east 8y ago
  Why? It's the same information.
gravy 8y ago
Nomenclature: https://en.wikipedia.org/wiki/Thule https://en.wikipedia.org/wiki/Thule
11thEarlOfMar 8y ago
Can a human jump off of Ultima Thule? https://xkcd.com/681_large/ https://xkcd.com/681_large/
- jake-low 8y ago
  Probably not, from the approximate sizes noted in the article it sounds like Ultima Thule is a bit bigger than Diemos, which XCKD says you could escape with a bicycle and a ramp. And just for fun, I also worked out a best guess for the force between the two "lobes": 1.5 x 10^13 N (assuming Ultima Thule is the same density as our Moon), which is about equal to the (Earth) weight of all the ships in the world. [0] [0]: https://what-if.xkcd.com/33/ https://what-if.xkcd.com/33/
- gshubert17 8y ago
  Modeling it as two spheres, one 16 km across the other 12 km, with a density the same as water, its total mass would be about 3*10^15 kg. At a distance of 8 km from the center of mass, the escape velocity [0] would be about 7 meters/second or 16 miles/hour. But the asymmetry of Ultima Thule means that its gravitational field would be weird. Not like a sphere at all. So the acceleration of gravity and escape velocity would vary a lot from place to place. [0] https://en.wikipedia.org/wiki/Escape_velocity https://en.wikipedia.org/wiki/Escape_velocity
yotapan 8y ago
Are the aliens throwing stones at us?
remote_phone 8y ago
What an astounding feat! I remember reading they were going to aim for 2000 miles from Ultima Thule, was the closest approach revised to 18,000 miles?
- JshWright 8y ago
  No, this photo was taken before the closest approach (note the very high sun angle, there's basically no shadows, so the probe was still inside the orbit of UT when the photo was taken). It's going to be another month before we see the closest/highest resolution photos (and years before all the data is downloaded)
ryanmercer 8y ago
Um, is that BB-8? Mimas (and Iaepetus too) really looks like the Death Star and now this thing looks like BB-8. Ultima Thule-BB-8 comparison: https://pbs.twimg.com/media/Dv7psG3VYAA8jqa.jpg https://pbs.twimg.com/media/Dv7psG3VYAA8jqa.jpg Mimas-Death Star comparison: https://cdn-images-1.medium.com/max/575/1*nUxm5MD_2xO5Y9LorrV8FQ.jpeg https://cdn-images-1.medium.com/max/575/1*nUxm5MD_2xO5Y9Lorr... Iaepetus-Death Star comparison: https://cdn.images.express.co.uk/img/dynamic/80/750x445/829007.jpg https://cdn.images.express.co.uk/img/dynamic/80/750x445/8290...
monster_group 8y ago
I highly recommend reading the book Chasing New Horizons by Alan Stern[0]. It is a great insight into years of work it takes to get a mission like New Horizons going. It is a very well written book and I could not put it down until finished. [0] https://www.amazon.com/Chasing-New-Horizons-Inside-Mission/dp/1250098963/ref=sr_1_1?ie=UTF8&qid=1546475775&sr=8-1&keywords=alan+stern+-+chasing+new+horizons https://www.amazon.com/Chasing-New-Horizons-Inside-Mission/d...
- Fuzzwah 8y ago
  Thanks for the recommendation, I was happy to find it available on audible.
sova 8y ago
It's a snowman with a snowman for a face! (recursive / fractal structures of the early world) space fern!
microDude 8y ago
The lack of craters is interesting.
Rooster61 8y ago
Kind of sucks that this is the big first picture that is being published. The LORRI, while an impressive piece of hardware in and of itself, is not built for high detail, close-in shots (although it was used some for the Pluto flyby closeups). That's the job of the Ralph telescope on-board the spacecraft. It's a neat picture, but I fear that any subsequent pictures will have less impact on the public, as many laymen will say "Meh, saw that the other day on <insert_news_site>. Old news". I'm really looking forward to the spectacular shots we will get from the close-in imager. New Horizons will be MUCH closer to this object than it was Pluto, so it should really get some fantastic shots of the surface features. For comparison, just check out the wikipedia pages. They show a pretty solid contrast of the capabilities/uses of the two devices: https://en.wikipedia.org/wiki/Long_Range_Reconnaissance_Imager https://en.wikipedia.org/wiki/Long_Range_Reconnaissance_Imag... https://en.wikipedia.org/wiki/Ralph_(New_Horizons) https://en.wikipedia.org/wiki/Ralph_(New_Horizons)
pvaldes 8y ago
Can't help to mention that several round stones stacked in balance is so artificial that is an 'universal' sign to mark the path in wild remote areas. A typical I was here sign.

697 points by mbrundle 8y ago

I find it truly amazing that New Horizons was able to take photos of a 20 mile object whilst flying past at ~8 miles/sec - that’s an incredibly small space and time window within which to capture the images. Does anyone know how NASA manages to pilot spacecraft with this level of precision? What kind of engineering processes do you need to enable this?

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jameskilton 8y ago
Actually doing the fly-by is less impressive (the fly-by was planned and programmed a while ago) than the fact that we were able to line up Horizons to an object like this at all! https://twitter.com/Alex_Parker/status/1077986070128668674 https://twitter.com/Alex_Parker/status/1077986070128668674
- weavie 8y ago
  I find it more impressive and awe inspiring that stuff in space is so predictable that we can actually program the fly by such a long time in advance and get such a high degree of accuracy.
  - dnautics 8y ago
    have you ever done course corrections in KSP? A tiny nudge early on is enough to make a huge difference farther out!
    - TeMPOraL 8y ago
      Yup. And if you've ever done maneuvers manually in KSP, you know that a tiny error in your nudge early on - e.g. hamfisting the throttle, or being a little too late in mid-maneuver staging - leads to a huge difference farther out, which you then have to correct, wasting precious ∆v :). I'm very much impressed by the control precision of real-life space probes.
      - dnautics 8y ago
        ah yes, you are commenting on the precision not on the magnitude of the displacement!
      - brianpgordon 8y ago
        Check out the crazy journey Rosetta took on the way to 67P/Churyumov–Gerasimenko: https://commons.wikimedia.org/wiki/File:Animation_of_Rosetta_trajectory.gif https://commons.wikimedia.org/wiki/File:Animation_of_Rosetta...
        theon144 8y ago
        Wow, I actually had no idea; how is this all pre-planned, does somebody at NASA just put "67-P/Churyumov" into a "Orbital Maneuver Planner" and let some computers crunch the possible paths out? Or does someone actually sit down and come up with the possible sequence of orbital assits (to later verify with a computer) with a pencil and paper?
        ironcan 8y ago
        Just a correction, but it's a project of the European Space Agency, not NASA.
        lokedhs 8y ago
        It's a combination of both. They have tools that help worth the trajectory calculations, but they have to manually decide on the basic layout of the path to take. There is a very interesting interview with Pablo Munoz from the Bepi Colombo team about flight dynamics on the Omega Tau podcast that explains this: http://omegataupodcast.net/295-bepicolombo/ http://omegataupodcast.net/295-bepicolombo/ The other interviews on the same episode are also worth listening to. In fact, the entire podcast is great.
    - joaomacp 8y ago
      I think everyone with an interest in spaceflight should play Kerbal Space Program. It gives you a sense of scale, both of space and time (luckily you can fast-forward to 100.000x), and also teaches you the basics of making orbital trajectories and correcting them, landing on planets/moons with different gravity... I'm really glad to have played it!
  - aurailious 8y ago
    My understanding was that the exact position was known within a few hundred miles of precision using both Hubble and the NH's cameras.
  - kamaal 8y ago
    Even more so given that how do you navigate these things in space, I mean its position. Given how large space is, and there is no map etc. It's just insane. I guess every press of button needs to be planned years in advance.
  - mpweiher 8y ago
    I also find this somewhere between impressive and amazing. However... ...after watching the Dragon/ISS docking manoeuvre for quite a bit longer than I probably should have, I think I now understand this precision better. When we think of "flying" including flying in space, we automatically have an image of something that's a bit unstable, always being buffeted a little, because that's how all the flying we are familiar with is. Actually seeing that docking manoeuvre, you get a feel for just how stable things are in space. When the Dragon is parked in its relative position (10m?) it is just there, rock solid, as if attached with steel beams. No, better, as if both parts are part of a single piece of granite. No quivering, nothing. Of course this is intellectually clear/obvious, but seeing it in practice is something different. https://www.youtube.com/watch?v=ysyK-J0tkEk https://www.youtube.com/watch?v=ysyK-J0tkEk
hcrisp 8y ago
I searched for "New Horizons GNC" and this link came up [1]. "The AOCS/GNC (Attitude and Orbital Control System / Guidance Navigation and Control) subsystem takes care that a spacecraft points to a specific point in space, determines the s/c attitude, and does trajectory corrections." [1] https://space.stackexchange.com/questions/9556/how-does-new-horizons-control-its-attitude https://space.stackexchange.com/questions/9556/how-does-new-...
ilkkao 8y ago
In the press conference they said that the spacecraft tried to take one megapixel image of Ultima Thule one hour after this image. Interesting to see it in couple months.
- tabtab 8y ago
  It will be a giant blurry thumb, just like my vacation photos. Except maybe green and glowing this time.
gibolt 8y ago
For a more detailed summary of the amazing collaborations necessary and challenges faced, Scott Manley: https://youtu.be/ymJRlUQfPfQ https://youtu.be/ymJRlUQfPfQ
- macleginn 8y ago
  They actually managed to predict the bi-lobed shape by keeping track of when the shadow of the object swept different points on the Earth’s surface. Amazing.
  - scrumbledober 8y ago
    I watched that video and when the pictures finally came out i was completely floored by how accurately they were able to predict the shape. An incredible problem solving strategy that seems very simple in hindsight.
dekhn 8y ago
the development of double precision floating point, and the kalman algorithm, were two major improvements. Basically there is a computer at JPL that, given a location in the solar system and a current location of a ship, will give you instructions on when to burn. After you burn fuel to move, you update based on visual locations of known stars, fit a model, and do incremental burns until convergence. The book Digital Apollo touches on a wide range of issues associated with building systems that can do this.
- karmakaze 8y ago
  > the development of double precision floating point So refreshing to hear that a double is good enough for JPL when repeatedly told it's not good enough for mere dollars and cents.
  - perl4ever 8y ago
    New Horizons is a mere few billion miles/km away, while financial matters these days sometimes involve trillions. Plus extra digits for cents and fractions thereof, of course. “There are 10^11 stars in the galaxy. That used to be a huge number. But it’s only a hundred billion. It’s less than the national deficit! We used to call them astronomical numbers. Now we should call them economical numbers.” - Richard Feynman
    - dekhn 8y ago
      i know you're joking but it's really the precision at large numbers that makes doubles so valuable. Typically when somebody is steering a spacecraft to a remote location, the large distance as well as the fine precision needs to be represented. I am not aware of people working with very large sums of money who also need penny-level precision (and even then, floats aren't the right solution).
  - planteen 8y ago
    JPL also has PhD applied mathematicians on staff to ensure numerical stability of their algorithms at double precision. Most developers do not have the ability to do that sort of non-trivial analysis. They are not just blindly saying "a double is good enough."
lisper 8y ago
> photos of a 20 mile object whilst flying past at ~8 miles/sec Not to detract at all from the astonishing technical achievement, but that's the wrong comparison. You can see the ISS with your naked eye, and it's a <1 mile object flying past at 4.8 miles/sec. The right comparison is with the distance at which this photo was taken: 18,000 miles, or about half an hour from closest approach. Actually, the right comparison is of the closest approach distance (~2000 miles) with the distance from earth (4,000,000,000 miles). That's like launching a missile from Los Angeles to New York and hitting your target to within a meter.
- jdmichal 8y ago
  To be fair, while that's an accurate representation of the distances, it's not accurate of the difficulty. They don't have to deal with unpredictable atmosphere. There's reasons laser-guided missiles are about 1-2 meters-ish of accuracy with constant guidance, while we can basically fire-and-forget spacecraft to 4 billion miles away.
  - Retric 8y ago
    Spacecraft also do some corse corrections. You can also measure where your going very accurately averaging over a few hours.
  - dwaltrip 8y ago
    They do have to deal with accurately determining the target destination, especially so in this case.
  - lisper 8y ago
    No, that's actually not true. Hitting Ultima-Thule is much harder. For starters, just figuring out where U-T actually is is very difficult. The observations we have only constrain two of its three degrees of orbital freedom. The third has to be inferred via orbital mechanics. Likewise, figuring out where the spacecraft is is also non-trivial. By way of contrast, figuring out where you are relative to New York to within a meter of accuracy is, nowadays, a simple matter of switching on your GPS receiver. (Even without GPS, all you need is inertial guidance that is stable for half an hour or so. That's much easier to achieve.) Finally, there are unpredictable orbital disturbances. N-H uses thrusters for attitude control, whose effect on the trajectory is not entirely predictable. (c.f. https://en.wikipedia.org/wiki/Pioneer_anomaly https://en.wikipedia.org/wiki/Pioneer_anomaly, which was only detectable because, although Pioneer had thrusters, they were turned off for long periods of time). I know these things because I used to work at JPL. There are entire teams dedicated to spacecraft navigation. The stuff they do will blow your mind.
tabtab 8y ago
Re: able to take photos of a 20 mile object whilst flying past at ~8 miles/sec...Does anyone know how NASA manages to pilot spacecraft with this level of precision? I cannot speak for this probe, but other probes have made the probe itself or camera boom move slightly to compensate for the target moving relative to the probe. It's kind of like moving your head back and forth to follow a tennis match if your eyes alone have difficulty tracking. The object looks like BB-8. We'll get even better pics in the coming weeks.
ohiovr 8y ago
Not to mention seeing it in practically pitch black darkness
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jimijazz 8y ago

This is why I love HN: because I can count to have updated links to content I care for.

HenryBemis 8y ago
And I logged in a few mins ago just to post this, but I am happy to see the community is like-minded!!
scrumbledober 8y ago
I've been getting most of my updates for this from /r/space personally, but I think that's the main attraction of HN for me. I don't need to curate my own list of subreddits to get links to content that interests me, because it's all (mostly) likeminded people on here that are on average interested by the same kind of stuff as me. I find more new interests on here than I ever could on reddit looking through my preconceived list of interests.
- deleted 8y ago
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deeths 8y ago

Here's a link to the press conference slides: http://pluto.jhuapl.edu/News-Center/Press-Conferences/index.php?page=2019-01-02 http://pluto.jhuapl.edu/News-Center/Press-Conferences/index....

skunkworker 8y ago

That is amazing. It reminds me of a snowman or two snowballs frozen together, except it's red not white. As seen in the combined image. http://pluto.jhuapl.edu/Galleries/Featured-Images/pics800wide/MU69_image_v1%20copy.png http://pluto.jhuapl.edu/Galleries/Featured-Images/pics800wid...

kylek 8y ago
Reminded me of 67p (albeit that is slightly more rubber-ducky shaped) https://en.wikipedia.org/wiki/67P/Churyumov%E2%80%93Gerasimenko https://en.wikipedia.org/wiki/67P/Churyumov%E2%80%93Gerasime...
compsciphd 8y ago
my caption to the article that I posted to facebook was "do you wanna build a snowman", so I guess thinking along the same lines :)
stcredzero 8y ago
It reminds me of a snowman or two snowballs frozen together, except it's red not white. The 21st century world of asteroid and Kuiper belt colonization is going to be far fluffier and squishier than we thought it would be in 80's Sci-fi!
rhizome 8y ago
Comet 67P has a similar shape. I have to wonder if there's something inherent in these flying rocks that causes them to take a dumbbell shape.
- antonvs 8y ago
  The inherent factor is collision, which is what forms most objects like this.
TeMPOraL 8y ago
Huh, given the color photo, it reminded me of a potato. Yes, I really did find a potato looking like this once.

jacquesm 8y ago

Absolutely amazing that they nailed the shape so well based on the occlusion data. That is super impressive.

tomerico 8y ago
From /r/space: Image of the occultation profile vs actual shape: https://i.imgur.com/PNh4nmX.png https://i.imgur.com/PNh4nmX.png Each line is the same star viewed from a different point on Earth. They arranged for telescopes in a long line North to South to all observe UT at the same time, just as it was predicted to pass in front of the star. Then they precisely timed the apparent blinks of the star. The North-South offset meant the star bisected UT across different sections for each telescope. Then they just worked out the parallax difference and mapped out the blink times on a chart to see the silhouette.
- 6nf 8y ago
  From that pic it looks like they were able to measure accurately to within meters of the actual shape at this distance! That is incredible
  - jcims 8y ago
    Those streaks in that pic are the path of a star that UT passed. Given they know the velocity, if they time the period where the light from the star is occluded, they get a measure of how wide the object is at that elevation. This is what an occultation looks like: https://www.youtube.com/watch?v=7Y_qc8Ifhso https://www.youtube.com/watch?v=7Y_qc8Ifhso Crazy they are able to map a few of those together so precisely to get this data.

quakeguy 8y ago

"The team says that the two spheres likely joined as early as 99 percent of the way back to the formation of the solar system, colliding no faster than two cars in a fender-bender." Welded together by gravity, i'm really in awe seeing the, by far, weakest power so lovely at work.

robotrout 8y ago
So, two masses were close enough in relative velocity and vector, that one of them didn't careen off the other one, and instead, allowed the weakest of all known forces to bond them together as they hurtled at high velocity through space. This object(s) seem statistically unlikely to me. I'm not saying it's artificial. That would be even more unlikely, by orders of magnitude. Just saying "Wow!".
- hughes 8y ago
  As this is the first Kuiper Belt Object we've visited, it's hard to draw much about the statistics of the thing.
  - robotrout 8y ago
    If they're all like this one, that would be puzzling indeed! Well done Mr. Spock!
  - tempestn 8y ago
    What's exciting to me is, both the first interstellar object we've observed visiting our solar system (Oumuamua) and the first Kuiper Belt Object we've visited have been "unusual". That strongly suggests to me that the unusual is more usual than we would have suspected, which means there's probably a great deal of opportunity to increase our understanding of the universe!
    - hyperpallium 8y ago
      It's easier to observe bigger objects than smaller objects. Bigger objects have greater gravity than smaller objects, therefore are more spheroid. As we get better at observing, we'll see more objects that are less spheroid.

samstave 8y ago

I personally find it amusing and interesting that the physical object, Ultima Thule, looks similar to the Virtual Game logo "Ultima" https://upload.wikimedia.org/wikipedia/en/6/6a/Ultima_Online_-_The_Second_Age_Coverart.png https://upload.wikimedia.org/wikipedia/en/6/6a/Ultima_Online...

wallace_f 8y ago
The nostalgia and innocence and discovry of childhood hit me so hard when I saw that logo
- tunnuz 8y ago
  I feel you.
- mhh__ 8y ago
  Quite interested as to by whom/why this was downvoted
  - CamperBob2 8y ago
    Forget it, Jake, it's HN

high_derivative 8y ago

Whenever I see these updates, I am reminded of the three body problem trilogy and its contemplations on space exploration (the parts I enjoyed the most). Then I get sad because things just take so incredibly long on a stellar scale, and a human life is so short.

ilamont 8y ago

The new images — taken from as close as 17,000 miles (27,000 kilometers) on approach — revealed Ultima Thule as a "contact binary," consisting of two connected spheres. Are these common in the asteroid belt or as smaller moons of the outer planets?

InclinedPlane 8y ago
As far as we can tell, they are pretty common. But we haven't visited enough objects to have firm statistics.

sizzzzlerz 8y ago

Pretty decent resolution of a object 27000 km distant. Has anybody seen the specs on what type of lens NH uses for images like this?

ihattendorf 8y ago
It's an 8" Ritchey–Chrétien telescope with a 1024x1024 pixel CCD camera. http://pluto.jhuapl.edu/soc/lorri_about.html http://pluto.jhuapl.edu/soc/lorri_about.html
azernik 8y ago
This is still nowhere near full resolution - it's at 140 meters per pixel, whereas the camera got 30 meters per pixel. It's going to take a few days to download the full images at 1kbps though.
- Avamander 8y ago
  Isn't it 1000baud than 1kbps?
  - Tor3 8y ago
    No, "baud" counts number of signal changes per second, which would equal number of bits per second in the old past (one bit encoded by one signal change). Ever since modems changed to e.g. quadrature encoding the number of bits per second would be higher than the baudrate. When somebody talks about bitrate these days then bps (bits per second) is what they should be using, not baud.

ajuc 8y ago

We only have 2 examples, but both this and the Rosetta mission object were rubber-duck-shaped. Is this very common?

peter303 8y ago
14 missions to comets, 20 to asteroids, and around 50 planetary small moons imaged well enough to see their shapes. Under a hundred miles in diameter many have irregular shapes. I would guess this shape only occurs a few percent of the time. Wednesdays news conference speculated UT shape is primordial, while the others may have been carved through four billion years of planetary evolution.
InclinedPlane 8y ago
It's pretty common. Based on radar data about 10-15% of Near Earth asteroids (larger than 200 meters) are contact binaries (or contact-binary shaped at least). We don't have enough data on main belt asteroids, trojan asteroids, and especially TNOs/KBOs to say what the percentages look like for those populations but it's a fair likelihood that the proportions are at least as high if not higher among KBOs.

azernik 8y ago

"hi-res" is relative - this is still about 5 times the feature size that was actually captured by the LORRI camera. Going to have to wait at least a few days for the glorious 30m/pixel version.

Avamander 8y ago
Some page wrote that it takes more than a year to get every piece of information about the fly-by.
- SubMachineGhost 8y ago
  Pluto's flyby generated about 8GB of data and it took about 16 months to get all of it downloaded [1], and this data includes more than just the images, and i read somewhere that the Ultima Thule flyby will generate about 6GB of data. I think the images are the first thing that get downloaded, so it should not take more than a week to get all high res images. 1 - https://en.wikipedia.org/wiki/New_Horizons#Telecommunications_and_data_handling https://en.wikipedia.org/wiki/New_Horizons#Telecommunication...
- azernik 8y ago
  20 months, actually.
hyperpallium 8y ago
It's hi-res for a playstation 1. substantive content: new horizons uses a modified MIPS R3000 CPU (ok, not the PSX's GPU, and not used for everything on NH, but) https://www.theverge.com/2015/1/15/7551365/playstation-cpu-powers-new-horizons-pluto-probe https://www.theverge.com/2015/1/15/7551365/playstation-cpu-p...

entity345 8y ago

Fantastic. Just one thing: it would be great if NASA dropped imperial units as main units in such articles.

herewulf 8y ago
I agree. However, the people that are paying for this mission still use imperial units. Those of them that are paying the most attention would probably agree with us though.
- perl4ever 8y ago
  US customary units are not imperial units. Many people don't realize, for instance, that MPG is not comparable between the US and the UK because gallons are substantially different.
perl4ever 8y ago
I don't think they use imperial units.
ars 8y ago
Why? What difference does it make? It's just a unit. It makes exactly 0 difference.
dev_north_east 8y ago
Why? It's the same information.

gravy 8y ago

Nomenclature: https://en.wikipedia.org/wiki/Thule https://en.wikipedia.org/wiki/Thule

11thEarlOfMar 8y ago

Can a human jump off of Ultima Thule? https://xkcd.com/681_large/ https://xkcd.com/681_large/

jake-low 8y ago
Probably not, from the approximate sizes noted in the article it sounds like Ultima Thule is a bit bigger than Diemos, which XCKD says you could escape with a bicycle and a ramp. And just for fun, I also worked out a best guess for the force between the two "lobes": 1.5 x 10^13 N (assuming Ultima Thule is the same density as our Moon), which is about equal to the (Earth) weight of all the ships in the world. [0] [0]: https://what-if.xkcd.com/33/ https://what-if.xkcd.com/33/
gshubert17 8y ago
Modeling it as two spheres, one 16 km across the other 12 km, with a density the same as water, its total mass would be about 3*10^15 kg. At a distance of 8 km from the center of mass, the escape velocity [0] would be about 7 meters/second or 16 miles/hour. But the asymmetry of Ultima Thule means that its gravitational field would be weird. Not like a sphere at all. So the acceleration of gravity and escape velocity would vary a lot from place to place. [0] https://en.wikipedia.org/wiki/Escape_velocity https://en.wikipedia.org/wiki/Escape_velocity

yotapan 8y ago

Are the aliens throwing stones at us?

remote_phone 8y ago

What an astounding feat! I remember reading they were going to aim for 2000 miles from Ultima Thule, was the closest approach revised to 18,000 miles?

JshWright 8y ago
No, this photo was taken before the closest approach (note the very high sun angle, there's basically no shadows, so the probe was still inside the orbit of UT when the photo was taken). It's going to be another month before we see the closest/highest resolution photos (and years before all the data is downloaded)

ryanmercer 8y ago

Um, is that BB-8? Mimas (and Iaepetus too) really looks like the Death Star and now this thing looks like BB-8. Ultima Thule-BB-8 comparison: https://pbs.twimg.com/media/Dv7psG3VYAA8jqa.jpg https://pbs.twimg.com/media/Dv7psG3VYAA8jqa.jpg Mimas-Death Star comparison: https://cdn-images-1.medium.com/max/575/1*nUxm5MD_2xO5Y9LorrV8FQ.jpeg https://cdn-images-1.medium.com/max/575/1*nUxm5MD_2xO5Y9Lorr... Iaepetus-Death Star comparison: https://cdn.images.express.co.uk/img/dynamic/80/750x445/829007.jpg https://cdn.images.express.co.uk/img/dynamic/80/750x445/8290...

monster_group 8y ago

I highly recommend reading the book Chasing New Horizons by Alan Stern[0]. It is a great insight into years of work it takes to get a mission like New Horizons going. It is a very well written book and I could not put it down until finished. [0] https://www.amazon.com/Chasing-New-Horizons-Inside-Mission/dp/1250098963/ref=sr_1_1?ie=UTF8&qid=1546475775&sr=8-1&keywords=alan+stern+-+chasing+new+horizons https://www.amazon.com/Chasing-New-Horizons-Inside-Mission/d...

Fuzzwah 8y ago
Thanks for the recommendation, I was happy to find it available on audible.

sova 8y ago

It's a snowman with a snowman for a face! (recursive / fractal structures of the early world) space fern!

microDude 8y ago

The lack of craters is interesting.

Rooster61 8y ago

Kind of sucks that this is the big first picture that is being published. The LORRI, while an impressive piece of hardware in and of itself, is not built for high detail, close-in shots (although it was used some for the Pluto flyby closeups). That's the job of the Ralph telescope on-board the spacecraft. It's a neat picture, but I fear that any subsequent pictures will have less impact on the public, as many laymen will say "Meh, saw that the other day on <insert_news_site>. Old news". I'm really looking forward to the spectacular shots we will get from the close-in imager. New Horizons will be MUCH closer to this object than it was Pluto, so it should really get some fantastic shots of the surface features. For comparison, just check out the wikipedia pages. They show a pretty solid contrast of the capabilities/uses of the two devices: https://en.wikipedia.org/wiki/Long_Range_Reconnaissance_Imager https://en.wikipedia.org/wiki/Long_Range_Reconnaissance_Imag... https://en.wikipedia.org/wiki/Ralph_(New_Horizons) https://en.wikipedia.org/wiki/Ralph_(New_Horizons)

pvaldes 8y ago

Can't help to mention that several round stones stacked in balance is so artificial that is an 'universal' sign to mark the path in wild remote areas. A typical I was here sign.