NASASpaceFlight.com Forum
NASA Shuttle Specific Sections => Atlantis (Post STS-135, T&R) => Topic started by: Chris Bergin on 11/09/2006 08:19 pm
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http://www.nasaspaceflight.com/content/?cid=4902
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Having seen the damage on Atlantis from STS-27 :o on the special video on L2, I'm not longer worried about gap fillers and holes like this
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What the hell are parts of other vehicles doing in the path of an orbiter? What is this, Russian roulette?
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To The Stars - 9/11/2006 9:08 PM
What the hell are parts of other vehicles doing in the path of an orbiter? What is this, Russian roulette?
This item was (thankfully!) a tiny speck of material from something that disintegrated.
There are tens of thousands of tracked pieces of space junk, and likely millions of specks like that one out in LEO. We've been busilly filling the orbits close to the Earth with space junk since Sputnik.
If we don't get more disciplined about burning up obsolete or dead spacecraft and related hardware, eventually we'll have enough junk to make that kind of an event commonplace.
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Well, the trouble is...there's all sorts of stuff floating around all over the place. There are exploded stages, failed satellites, brackets, screws, gloves, just about anything else you can think of used to paint, fasten, glue, or otherwise assemble a spacecraft. Most of these items are so small they cannot be detected by ground radar or infrared tracking, but the sources of this small debris is generally big enough to track. The other thing is that for the small items, like paint chips and pieces of broken circuit boards, if they are in fairly highly elliptical orbits, their trajectories will end up being chaortic because they will be perturbed by solar light pressure, solar activity raising the upper atmosphere, etc. So even if you know where they are now will not necessarily let you know where they will be in the future with any great degree of confidence. The only way to get rid of this stuff is to find the sources and deorbit them--which is a very, very tall order. Now trajectory engineers generally make sure that upper stages end up in disposal orbits or trajectories that either immediatlely or in fairly short order will drop them back into the atmosphere to burn up.
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To The Stars - 9/11/2006 11:08 PM
What the hell are parts of other vehicles doing in the path of an orbiter? What is this, Russian roulette?
Welcome to the future of spaceflight! Everything that we launch is a future piece of space junk, so the problem is only going to get worse unfortunately.
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...especially if the bigger pieces collide with one another and make millions more little, itsy, bitsy pieces!...then real, catastrophic erosion of everything in LEO could happen, and then it will be years before it's cleared out!
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Old Delta (before Delta II) and Ariane (1, 2 or 3) upperstages use to explode days/months after their use. They both used common bulkhead hypergolic tanks. After some time in orbit, the pressurization tanks would leak gas and overpressurized the propellant tanks, causing them to explode. The remedy was to have the stages perform a depletion burn after the nominal mission was over and also vent down all other tanks.
All US spent stages must inert themselves and either reenter as part of launch or have an orbit with a duration longer than 25 years
The debris from these and other LV's (some Centaurs, Agena, other countries hardware) and some spacecraft, too, have over time created a halo around the earth. There is no way to find out where this came from
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Thanks for the info, Jim, now we know the mechanism.
And yet again, small short-sighted savings bring much bigger problems in the long run. Cleaning always costs 1000x than not trashing / polluting in the first place.
I wonder if other countries have adopted anti-debris measures. If not, they definitely should!
It's related to a problem in economics known as "The Tragedy of the Commons", having something that nobody owns but everybody can take from, hence everybody is exploiting it as fast as to get an advantage over someone else.
Industrialized humans can have such a big impact on many resources and features on Earth that they should no more be considered unlimited, but their use should be regulated.
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The article speculates on the damage that a high density fragment of the same size might have caused. I was wondering whether the damage will increase only with mass, or will density play a part, for two debris objects with the same impact velocity? In concrete terms, if a metal shard and a circuit board fragment of the same mass impact a vehicle at the same speed, will there be a difference?
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lower density would "spread" the kinetic energy over a larger surface area and therefore, allowing more energy to be dissapated into the surface
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If this is the second largest MMOD strike, what's the largest? I've looked around and haven't been able to find any information about it.
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kanathan - 14/11/2006 9:25 PM
If this is the second largest MMOD strike, what's the largest? I've looked around and haven't been able to find any information about it.
I believe it was STS-59