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NASA just sent a software update to a spacecraft 12B miles away

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Re: NASA just sent a software update to a spacecraft 12B miles away

#291

Post by mattkrause »

ben_w wrote: post #215
_8j50 wrote: post #118

Earlier quoted context omitted.

Metric doesn't let people grasp large numbers.

Metric is neither better or worse than anything else, in that regard. Describing a distance as "4 Plutos" isn't that helpful when Pluto is too dim to see with the naked eye, and still only a dot with a good ground-based telescope. Even smaller distances like "AU" are too big for a human mind, with the Earth itself being less than a pixel across if the orbits were drawn to scale on an 8K monitor.

> still only a dot with a good ground-based telescope.

That gives a pretty good feel for how far away it is!

Re: NASA just sent a software update to a spacecraft 12B miles away

#292

Post by eszed »

SoftTalker wrote: post #251
zrail wrote: post #195

Earlier quoted context omitted.

UBI and universal healthcare would enable _so_ many people to take risks that they can't today. We would see an explosion in the arts, in fundamental science, in passion projects like this. It would be absolutely incredible. Except according to half of the people in charge it would mean The Wrong People would get money and all they would do is buy drugs. And that's why we can't have nice things.

This is a tangental subject but I disagree. I think this is one of the many excuses used by people who feel pressure to be entreprenurial but in their hearts are not risk-takers. And that's OK -- the world needs a lot of people who work for others. If you are a risk taker, especially a young one, lack of UBI or health insurance is not going to stop you. It never has in the past, when those things didn't exist.

Your "especially a young one" is doing a lot of work.

I anecdotally know a number of people, both in and out of tech, who would prefer to be independent contractors or small-business owners - in fields that they know well, and stand better than even chances of ending up with higher total compensation - but have families. Their fear of losing healthcare benefits (temporarily, whilst they get their businesses off the ground; or longer-term, should their businesses fail) keeps them working for others.

The sibling post about "calculated risk" is correct. The conclusion these folks have made (not to strike out on their own, under current circumstances) is likely the correct one, but it's a continual drag on total economic potential. Worse, this is a cost which isn't captured by calculations of what's currently spent on health-care, nor can be off-set against what a more robust social safety net would "cost". It is, nevertheless, considerable.

Re: NASA just sent a software update to a spacecraft 12B miles away

#293

Post by dredmorbius »

simpaticoder wrote: post #198
qrybam wrote: post #31

This is incredible. Not just because of the engineering that went into such a long lived machine, but also because of the ingenuity of the teams that have looked after this mission and those currently working on it. Half a century of operation. Bits of data, like gold dust, peppering our radio telescopes with telemetry from the edges of our protective solar shell, and beyond. Not only is the technical achievement som…

>Half a century of operation. The stability of society (specifically American, specifically California/Caltech/JPL/Pasadena) must also be marveled at. That's 2 or 3 generations of engineers and scientists that were trained well enough to actually get things done. This is a marvel of teaching, technical communication, and societal infrastructure. Notably, NASA/JPL has maintained its prestige and funding for that entir…

The thought occurred to me some years ago that a key aspect of governmental institutions is their durability, particularly in the face of adversarial politics. Though the inefficiency of government services is quite often grossly exaggerated, there's much consideration which has to be made of the trade-offs between efficiency and durability.

This should be front-of-mind whenever someone proposes a start-up to address some long-standing social, societal, and/or political issues:

https://news.ycombinator.com/item?id=12345506>

The other institutional forms which seem to tend toward durability are educational and religious institutions. Which often overlap considerably.

Re: NASA just sent a software update to a spacecraft 12B miles away

#294

Post by ben_w »

mattkrause wrote: post #291
ben_w wrote: post #215

Earlier quoted context omitted.

Metric is neither better or worse than anything else, in that regard. Describing a distance as "4 Plutos" isn't that helpful when Pluto is too dim to see with the naked eye, and still only a dot with a good ground-based telescope. Even smaller distances like "AU" are too big for a human mind, with the Earth itself being less than a pixel across if the orbits were drawn to scale on an 8K monitor.

> still only a dot with a good ground-based telescope. That gives a pretty good feel for how far away it is!

What? No it doesn’t, you need to know how big it is for that, and most people don’t have a sense of scale that encompasses either the full size of Earth (how far have you tried hiking, even over multiple days? If it was the Pacific Crest Trail congrats but you’re unusual) nor the size range of planets.

Most stars (and galaxies) can be described with the same words I just used for Pluto, but stars and galaxies are thousands to trillions of times further away than Pluto.

Re: NASA just sent a software update to a spacecraft 12B miles away

#295

Post by dredmorbius »

infinitedata wrote: post #146

I wonder which checksum algorithm they use at those ultra low latencies. Amazing work

There are some papers discussing this, e.g.:

"Polar Coding for Forward Error Correction in Space Communications with LDPC Comparisons", Naveed Namipour, Haleh Safavi, & Harry Shaw.

https://ntrs.nasa.gov/api/citations/20190032244/downloads/20...>

Also "Design of Low-Density Parity-Check (LDPC) Codes for Deep-Space Applications" https://ipnpr.jpl.nasa.gov/progress_report/42-159/159K.pdf>

The first specifically discusses early missions.

Re: NASA just sent a software update to a spacecraft 12B miles away

#299

Post by dredmorbius »

tg16 wrote: post #273
grishka wrote: post #144

Earlier quoted context omitted.

But the more copies you make of something, the cheaper they become. The R&D cost is the same and is only paid once whether you're building 2 space probes or 2000.

The probe itself is a relatively insignificant cost. The launch costs and timing windows are the limiting factor. The tyranny of the rocket equation is the fact that to carry more fuel to orbit, you need more fuel to get it into orbit, which itself needs more fuel. That's why gravity assists are so essential for escaping the solar system on a budget. The planetary alignment that enabled the Voyager launch windows onl…

The specific alignment for the Voyager missions was to permit flybyes of all the gas giants: Jupiter, Saturn, Uranus, and Neptune, with only two spacecraft. Both V1 & V2 visited Jupiter and Saturn, with Voyager 2 continuing on to both Uranus and Neptune. All visits were flybyes, that is, the probes were within the vicinity of the target planets, but did not orbit them for any prolonged length of time.

More conservative trajectories giving fewer flybyes but relying on more probes would be possible, and are in fact what we've accomplished with the Gallileo & Juno (Jupiter), Cassini-Huygens (Saturn), and New Horizons (Pluto) spacecraft. There are NASA (U.S.) and Chinese proposals for a return visit to Uranus and Neptune, though those remain in planning stages.

https://www.space.com/nasa-uranus-orbiter-and-probe-mission-...>

The orbiter missions had a much longer time-on-station. For Gallileo, roughly 7 years 9 months, Cassini-Huygens 13 years, and Juno 7 years to date, with another 5 or more possible.

The Ulysses solar probe also flew past Jupiter, using the planet for an orbital assist to both slow it down to approach the Sun more closely and incline its orbit above and below the planetary plane so that the Sun's poles could be observed directly.

Re: NASA just sent a software update to a spacecraft 12B miles away

#300

Post by mdaniel »

shiroiuma wrote: post #79
quietpain wrote: post #58

Earlier quoted context omitted.

Lets hope the _archival_ effort can match or in 50 years time we’ll have another one of these: https://en.m.wikipedia.org/wiki/Apollo_11_missing_tapes https://en.m.wikipedia.org/wiki/Stolen_and_missing_Moon_rock...

Even with those problems, those are still far better than the (complete lack of) documentation I see in software workplaces these days.

In fairness to the workplaces that I've been in, documentation for a software stack, or even the product, from 18 months ago may as well be in Swahili for as much good as it would do any new member to the team

Just like the comparison to code quality I often see is any such NASA thread: it's a whole different ballgame when one is sending a spacecraft out, or carrying lives to space, than "I tried to send a Slack message and it did a sowweee,oopsiez"

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