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New Horizons’ first hi-res imagery of Ultima Thule

pluto.jhuapl.edu

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Re: New Horizons’ first hi-res imagery of Ultima Thule

#121

Post by deeths »

weberc2 wrote: post #120
tabtab wrote: post #49

Earlier quoted context omitted.

Re: first Kuiper Belt Object we've visited Pluto may be a KBO also. Further, it's possible some moons of the gas-giant planets are captured KBO's. The unusual thing about Ultima Thule is that it's in a nearly circular and "flat" orbit, which many experts interpret to mean it's mostly undisturbed from its point of origin. It's a prime "fossil". Pluto has a "disturbed" orbit such that its origin is currently unknown. S…

> Pluto has also been turned inside-out, perhaps multiple times, by a still unidentified force. Whoa, come again? How do we know this? What does it mean for a planet-like object to be turned inside out?

Inside out just means that the local equivalent of Earth's geologic plates seem to be subducting below the surface and fresh geologic plate equivalents are abducting back up. You can estimate how long a planetary surface has been exposed to the elements by the statistical distribution of number and size of craters. We have a reasonable idea of the likelihood of objects impacting Pluto, and it should have a lot of craters. Pluto's moon Charon has many more visible craters but Pluto has large areas with no large craters, so some sort of geologic process must be going on that's recycling areas of the landscape and covering or subducting the craters.

Given lack of fast erosion from liquid water or significant wind (in a very thin atmosphere), whatever geologic process is smoothing out Pluto is happening quickly compared to other points of reference we have.

I use the example of Earth's geologic plates, but that's only one possible explanation. There's also speculation about freeze/thaw cycles of the planetary material and atmosphere (since it has an irregular orbit), movement of water-ice mountains, cryovolcanos, and other theories.

Some examples: https://www.nasa.gov/sites/default/files/thumbnails/image/du... https://www.nasa.gov/sites/default/files/thumbnails/image/nh... https://www.nasa.gov/sites/default/files/thumbnails/image/co... https://www.nasa.gov/sites/default/files/thumbnails/image/nh...

Re: New Horizons’ first hi-res imagery of Ultima Thule

#122

Post by kzrdude »

lisper wrote: post #44
jdmichal wrote: post #35

Earlier quoted context omitted.

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.

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 with…

Thanks for the link, didn't know the pioneer anomaly had a conclusion.

Re: New Horizons’ first hi-res imagery of Ultima Thule

#123

Post by Tor3 »

Avamander wrote: post #90
azernik wrote: post #51

Earlier quoted context omitted.

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.

Isn't it 1000baud than 1kbps?

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.

Re: New Horizons’ first hi-res imagery of Ultima Thule

#124

Post by JoeSmithson »

tempestn wrote: post #27
hughes wrote: post #22

Earlier quoted context omitted.

As this is the first Kuiper Belt Object we've visited, it's hard to draw much about the statistics of the thing.

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!

They deliberately picked targets that seemed unusual from initial readings.

Re: New Horizons’ first hi-res imagery of Ultima Thule

#125

Post by azernik »

Avamander wrote: post #89
azernik wrote: post #52

"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.

Some page wrote that it takes more than a year to get every piece of information about the fly-by.

20 months, actually.

Re: New Horizons’ first hi-res imagery of Ultima Thule

#126

Post by Fuzzwah »

monster_group wrote: post #84

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/d...

Thanks for the recommendation, I was happy to find it available on audible.

Re: New Horizons’ first hi-res imagery of Ultima Thule

#127

Post by mikeash »

karmakaze wrote: post #98
dekhn wrote: post #25

Earlier quoted context omitted.

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…

> 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.

It’s good enough for dollars and cents if you put thought into it, but you can’t just represent money as double-precision dollars and expect to get the results you need.

Re: New Horizons’ first hi-res imagery of Ultima Thule

#128

Post by kamaal »

weavie wrote: post #45
jameskilton wrote: post #5

Earlier quoted context omitted.

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

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.

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.

Re: New Horizons’ first hi-res imagery of Ultima Thule

#129

Post by kamaal »

lisper wrote: post #33
mbrundle wrote: post #2

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?

> 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 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…

>>That's like launching a missile from Los Angeles to New York and hitting your target to within a meter.

As long you have navigation(GPS) and fuel(to make adjustments), that shouldn't be a problem?

But of course you don't have a map in space, so how do you navigate, and course correct etc, is another big puzzle in itself.

Re: New Horizons’ first hi-res imagery of Ultima Thule

#130

Post by kamaal »

lisper wrote: post #44
jdmichal wrote: post #35

Earlier quoted context omitted.

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.

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 with…

>>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.

How do we get to work with these teams, if even possible?

(Though it should be impossible for me(given I'm an Indian), still how do someone who could work there go about joining them)

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