I heard on NPR News this morning that the Russian Space Command (or whatever it’s called) just decided to follow the US’s advice and junk their space station (Mir) so they could focus their rubles on the International Space Station.
They have plans to bring Mir down early next year.
My question: Why? Why not just leave Mir up there? I mean, there’s more than enough… er… space to go around, isn’t there? Even in close orbit to Earth?
It’s about time too, but then again, they have promised to bring down that station many times before and never went through with it.
The problem is that the space station, like the Shuttle and the ISS, are in low earth orbit, only a couple of hundred miles up. It’s high enough that they can stay up for years, but there is still a tiny amount of air up there. So eventually the friction with air will bring down the station. And an uncontrolled descent is not a good thing - big chunks of it will reach the ground and if it hits a populated area, someone could easily get hurt. So they want to crash it above the ocean when they still have control of the station.
It’s nothing new. Just this summer, NASA junked a perfectly functional astronomical satellite, the Compton Gamma-Ray Observatory. All but two gyros had failed on the satellite, and they determined that another failure can result in loss of control.
Think Skylab. Skylab was the U.S.'s first space station. It fell out of the sky in an uncontrolled deorbit in the '70s. Fortunately no one was injured - it fell in the Pacific (and empty parts of Australia?). However, it is not something that we would like to see risked again.
Is there anyway to salvage anything after it crashes? Maybe no way to tell before it crashes but was anything salvaged from other space junk?
If you just want souvenirs, sure. You can see pieces of Skylab at various museums. But I doubt any component would reach the ground in working order, and even if it did, nobody would trust it to continue working much longer.
The only exception is radioactive isotopes. Some deep-space probes use chunks of radioactive material as an energy source. This is not a nuclear reactor, they just use the heat given off by normal radioactive decay. The containers are designed to survive a fall from orbit, and the radioactive material is prescious and not harmed by the fall, so they would use it again. In fact, I think they’ve already done that at least once.
scr4, what you are talking about are the RTGs, Radioactive Thermoelectric Generators (url=“http://stuweb.ee.mtu.edu/~calubowi/ee280/contents.html”]here’s a FAQ on them). I believe the one that they reused was when they had to abort a launch after liftoff. I don’t think it fell all the way from orbit.
Let’s try that link again
You are right, thanks for the correction. I found some info here - basically the rocket malfunctioned and had to be destroyed in flight.
The page does list one RTG which survived a fall from orbit - it was on the Apollo 13 lunar module. It was supposed to be left behind on the moon to power the experiments.
Like scr4 said, left to it’s own devices, Mir’s orbit will eventually decay and crash down to Earth. It costs money to keep boosting it’s orbit back into place. NASA recently brought down the Compton satellite for the same reason. It’s safer to bring it down in a controlled manner than to let it crash at some random point on Earth.