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New Horizons’ first hi-res imagery of Ultima Thule

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

#101

Post by perl4ever »

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.

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

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

#102

Post by perl4ever »

herewulf wrote: post #64
entity345 wrote: post #54

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

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.

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.

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

#105

Post by nwallin »

brianpgordon wrote: post #60
TeMPOraL wrote: post #56

Earlier quoted context omitted.

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.

Check out the crazy journey Rosetta took on the way to 67P/Churyumov–Gerasimenko: https://commons.wikimedia.org/wiki/File:Animation_of_Rosetta...

Also the path BepiColombo is taking to Mercury:

https://en.wikipedia.org/wiki/BepiColombo#/media/File:Animat...

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

#106

Post by CamperBob2 »

robotrout wrote: post #19
quakeguy wrote: post #15

"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.

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!".

Remember, the Moon is covered with the results of astronomical odds.

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

#108

Post by hyperpallium »

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!

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.

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

#109

Post by michelpp »

theon144 wrote: post #78
brianpgordon wrote: post #60

Earlier quoted context omitted.

Check out the crazy journey Rosetta took on the way to 67P/Churyumov–Gerasimenko: https://commons.wikimedia.org/wiki/File:Animation_of_Rosetta...

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?

Common orbits are solutions to the two body problem, but Shane Ross has a few videos on youtube about chaotic solutions to the three body problem, allowing objects to move in very complex orbits with very little fuel. This has been used for a few missions as I understand it, the math is WAY above my head, but the video is still quite watchable with lots of cool orbit animations:

https://www.youtube.com/watch?v=FwHDEB1VS_0

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

#110

Post by hyperpallium »

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.

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-p...

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