Russian Satellite Hit by Debris from Chinese Anti-Satellite Test | Hacker News Reader

Russian Satellite Hit by Debris from Chinese Anti-Satellite Test

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64 pointspetrel31 comments

There's a very good 2003 sci-fi anime called Planetes[1] that explores the problem of space debris in some detail, and how humanity might deal with it in the future. Highly recommended if you're interested in these issues.

1. http://myanimelist.net/anime/329/Planetes

I was wondering if someone would mention Planetes. I'd still rank it as one of my favourite anime series, as it's such a plausible near-future sci-fi. Highly recommended.

Funny. The first thing I've remembered was Planetes.

Ah! Wonderful :) This is, in fact, a hard science fiction!

http://en.wikipedia.org/wiki/Planetes

"Unlike many other anime and science fiction productions, special care was given in Planetes for a very realistic depiction of space and space travel."

"The Japanese space agency JAXA served as a technical consultant to the series. The US version of the DVDs featured interviews with two scientists from NASA's Orbital Debris Section."

Thank you Sir for your very valuable recommendation. As a fan of Anime, specially SciFi Anime, I am eternally grateful to you for pointing me to this Anime. May the stars grant you eternal bliss.

By the way, even though this is a tangent, could you please name other Animes that you believe would be of interest? I'm sincerely interested in hearing any of your recommendations.

Anybody else feel free to chip in.

http://en.wikipedia.org/wiki/2007_Chinese_anti-satellite_mis...

http://celestrak.com/events/asat.asp

The mentioned Chinese test is single-handedly responsible for the vast majority of space debris.

I'm sure that's all just anti-PRC propaganda. </sarcasm> I'm waiting for the PRC state workers to astroturf that on in the comments.

I'm sure that's all just anti-PRC propaganda. </sarcasm> I'm waiting for the PRC state workers to astroturf that on in the comments.

Well, there ya go right below you :)

http://news.ycombinator.com/item?id=5352254

I wonder if Russia can demand compensation from China.

It's not like China wasn't warned - I remember tons of criticism of them before they launched, yet they did it anyway.

If you deliberately cause damage, you should be liable.

> The mentioned Chinese test is single-handedly responsible for the vast majority of space debris.

It was widely considered the most prolific single source of debris, but I don't think it's responsible for the majority of space debris.

NASA catalogged 900 or so pieces of space debris from the test exceeding 10 cm, expecting the number to climb to about 950 such pieces. [1]

In total, NASA tracks about 21,000 pieces of debris over 10 cm. [2]

Is largest single source getting confused with majority, or was more debris discovered after the fact?

1. http://www.space.com/3415-china-anti-satellite-test-worrisom...

2. http://orbitaldebris.jsc.nasa.gov/faqs.html#3

PS - Not trying to play 50 cent army here, "largest single source" is still definitely bad, just not the same as "vast majority."

Ah, I see now that my parent's sources list it as "largest debris-generating event" (celestrak) and "The test is the largest recorded creation of space debris in history with at least 2,317 pieces of trackable size (golf ball size and larger) and an estimated 150,000 debris particles." (wikipedia).

That tracks with what I saw, so take this as just a minor tweak to GP's phrasing.

Don't skip that post because of the oversight. The celestrak link offers an incredible HD video simulating the debris cloud and the path of the ISS... it's like an action movie. Great find, so I upvoted.

http://en.wikipedia.org/wiki/Kessler_syndrome

To save the click through:

As the chance of collision is influenced by the number of objects in space, there is a critical density where the creation of new debris occurs faster than the various natural forces remove them. Beyond this point a runaway chain reaction may occur that pulverizes everything in orbit.

There was a fun idea for a while to use a powerful laser to shoot at the front end of space debris. The resulting ablation would turn the little nuts and bolts into tiny rockets using their own material as fuel. http://en.wikipedia.org/wiki/Laser_ablation

See also: xkcd What If? on using laser ablation to propel the moon away from the Earth: http://what-if.xkcd.com/13/

The scary bit is that each collision generates a new debris field, which can in turn generate more new collisions, so the safety of orbit starts decreasing geometrically.

Yes, but what are the orbits of the debris and how quickly do they fall into the atmosphere or deep space?

It depends on the height. At the height of the ISS, is it about a year or less, at the height of the Chinese test is seems to be a few decades or maybe one or two centuries and at 1000km the lifetime of space debris starts to be measured in millennia. (Combining some numbers from http://www.dlr.de/en/desktopdefault.aspx/tabid-5170/8702_rea... , http://www.spaceacademy.net.au/watch/debris/sdfacts.htm and http://en.wikipedia.org/wiki/Space_debris . http://www.orbitaldebris.jsc.nasa.gov/faqs.html#12 gives numbers that are about a factor of ten smaller, and it also depends on the type of debris, a sheet of mylar experiences a higher drag than a steel nut of the same weight.)

> a sheet of mylar experiences a higher drag than a steel nut of the same weight.

Drag in space? At what altitude, more precisely, does the objects start to experiment drag or the lack of it therefore?

Yes, of course. That is the only mechanism that can remove debris from orbit (apart from flying up there and shooting lasers at it and other untested fantastic ideas). And debris in higher orbits survives longer exactly because the earth's atmosphere gets thinner and thinner the further you are from the surface. The upper boundary of the atmosphere is somewhere above 100000km (62000 miles) http://en.wikipedia.org/wiki/Exosphere#Upper_boundary

Oh, I thought it was gravity alone that did the work :) Thanks for explaining it.

Gravity doesn't do anything on its own, in the absence of other forces, the orbit of a steel nut around the earth would be stable (that's also why we haven't yet crashed into the sun even after being in its gravitational field for billions of years). (Well, you would get some instability because neither the earth nor the nut are perfect spheres or perfectly rigid, but those effects would take billions of years to become noticeable.)

"Gravity doesn't do anything on its own, in the absence of other forces, the orbit of a steel nut around the earth would be stable"

Actually, it wouldn't, because orbiting a celestial body radiates energy in form of gravitational waves, but in case of Earth's gravitational field and at the speed of orbiting satellites, this mode of losing energy is negligible.

Yes, but I still think that the tidal deformation of the earth under the gravitational influence of the steel nut will vastly dominate general relativistic effects like gravitational waves. You usually use neutron stars orbiting black holes to produce the latter.

> At what altitude, more precisely, does the objects start to experiment drag or the lack of it therefore?

There is no cutoff. It just gets less and less the higher you go, but there is no point where you can say "zero".

This is something I have been wondering for a while; assuming we could detect it, space debris around a body could be a serious indication of life on a planet, could it not?

Especially if it could stay around for so long. Though this assumes that the population of that planet is not nearly as trashy as our own.

I wish there were a requirement for all space-faring nations to clean up space debris.

When China conducted that test, Russia's Defence Minister called the reporting of it "exaggerated and abstract." This should make things more concrete.

I am wondering why the debris was not from US Anti-Satellite test? After all, US has done much more such tests secretly.

It's kind of hard to blow up a satellite secretly (as in, no one noticed).

The last US "test" was in 2008 to destroy a defunct spy satellite. Spy satellites have very low orbits (around 100km) and an overwhelming majority of the debris from that test reentered the atmosphere and burned up within weeks or months. Previous ASAT tests were done in the 80s and were also all at low altitude where debris burns up within a few months. The Chinese ASAT test was at around 1000km and much of that debris will be there for tens or hundreds of years. It basically undid all the work the international community had done on reducing debris over the past decade (http://www.scientificamerican.com/media/multimedia/0212-spac...).

It is possible, but highly unlikely that the US does ASAT tests in secret. It's unlikely mainly because any unannounced rocket launch looks suspiciously like an ICBM (and is easily detectable), so it is in everyone's best interest to announce launches ahead of time. If the US has done secret ASAT tests, they would continue to do them at lower orbits out of concern for debris.

The US tracks all objects in low Earth orbit that are about 10cm or greater in diameter using a large network of radar stations. The Russians have similar capabilities, though not on the same scale. As a result, they actually can tell where most of the debris came from. However in this article it was not clear if it was just conjecture or actual tracking data from the Chinese ASAT debris that led them to that conclusion.

The US performed its anti-satellite tests against targets in low Earth orbit, so that the orbits of the debris decayed quickly. That was not the case for the Chinese test, which was in a relatively high orbit and generated a huge amount of long-lived debris.

More so, the idea of "secret" anti-satellite tests is a bit rich, satellites are tracked by RADAR from multiple countries, you can't hide a satellite blowing up.

The Chinese are pretty minted, can they not buy the Russians a new one?

I don't see anything in the post claiming the purpose of the satellite, or if it was still operational.

So I would surmise the main point here is to highlight the increasing danger of space debris, and that the danger is going to be exponential, rather than linear in growth.

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