Atlantis struck by space debris?
Published on Oct 10, 2006 at 12:51 am.
1 Comment.
Filed under NASA, space debris, space exploration, space shuttle.
Last month, I did a posting on space debris. Towards the end of the post, I mentioned that NASA had seen something floating away from the Space Shuttle Atlantis. Well, now I have more to report. It appears that something apparently struck Atlantis while in orbit, though this incident appears to be unrelated to the debris floating away from the orbiter.
The mission went well, and other than worries about a lightning strike before the mission, and concern over debris floating away from the orbiter, it looked like nothing had gone wrong. Atlantis landed safely just before dawn on Runway 33 at the Kennedy Space Center in Florida on September 21, 2006 (seen above).
After every mission, NASA is supposed to go over each shuttle with a fine tooth comb. The original plans for the shuttle program were that these were supposed to be quick turnarounds, thus making missions less expensive and the shuttle program profitable. Well, quick turnarounds never materialized, and it soon became apparent that they could only be realized by shortcutting safety procedures to the point of endangering astronauts and spacecraft. So, the shuttle is scrutinized after each mission.
Well, this time, the people checking on the shuttle rather quickly discovered an impact feature on one of the radiators. The shuttle generates heat from the operation of equipment on board, and the temperature aboard the craft would become uncomfortably warm quickly, and then dangerously hot, were it not for the radiators attached to the insides of the cargo bay doors. This is one reason that the shuttle always flies with the cargo bay doors open, even if it is a mission that does not require anything being removed from the cargo bay. These radiators are essential to keeping the craft at a reasonable temperature.
Now, this hole that they found in one of the radiator panels wasn’t very big — only about 1/10 of an inch. Also, the impact did not rupture any of the coolant tubes, though it did damage some of the honeycomb-like heat dissipation structures surrounding those tubes. But, any hole is something to be concerned about. No one really knows what hit Atlantis. It may have been a piece of orbital debris, or it may have been a micrometeorite. We may never know, because the impacting body was vaporized by the impact, suggesting very high impact velocity. 
If news reports that the impactor was moving so fast that it vaporized are correct, then this leads me to believe that it may have been a very high enough impact velocity. Such a high velocity suggests that this may have been a micrometeoroid impact rather than an impact with a piece of man-made debris. If so, then there really wasn’t anything that could be done about it. About the only thing that can be done is to minimize such an occurance is to fly with the payload bay open facing Earth. That is, in fact, how the shuttle normally flies. However, for most of the mission, Atlantis was attached to the International Space Station rather than flying free. That may have been when the impact happened. The hole was small, and it never posed a risk to the orbiter. However, imagine what may have happened to an astronaut if such a meteoroid had hit him? This thing punched through a piece of aluminum. The astronaut only has a fabric suit protecting him. The impact likely would not only have penetrated the suit, but also the astronaut. This is one of the things that NASA has worried about since the dawn of the space age. This is also one reason that they are always freaked out whenever the astronauts do an extravehicular activity (spacewalk). The danger is always there, and there really isn’t much that you can do to minimize it.
Something to think about.
-Astroprof
(Images courtesy of NASA)
Astroprof’s Page » Yet more space debris on February 25, 2007 at 4:05 pm: 1
[…] Then, less than a week ago, a Russian rocket body exploded in orbit, creating an even larger cloud of debris. At least this was an accident, but that doesn’t make the debris cloud any less worrisome. The rocket body was the Briz-M (or sometimes Breeze-M) upper rocket stage for a Proton rocket launched on February 28, 2006. A malfunction of some sort caused the rocket to shut down early, putting a satellite destined for a geosynchronous orbit into a highly elliptical useless orbit. The rocket has been orbiting Earth for the past year. But, on February 19, it was determined that it had broken up. Likely it exploded. Whatever happened, it is now a cloud of space debris rather than an intact rocket. As with the Chinese satellite debris, the rocket debris cloud is slowly expanding and spreading out. Rocket bodies exploding are a known hazard. They are supposed to use up most of their fuel, but sometimes there is fuel left over in them. In this case, the engines shut off early, and there was quite a bit of fuel and oxydizer left. As the rocket orbits, it is constantly subjected to alternating cycles of freezing cold and baking hot temperatures. Eventually something breaks or comes loose with such thermal cycling. If the oxydizer and fuel meet, then can create an explosion, blowing the rocket to bits. Both debris clouds pose hazard to active and future satellites due to their orbits. Both have orbits that are high enough to stay out of most of the Earth’s atmosphere, and so some of this debris will likely persist for hundreds or even thousands of years. The more things that we put into space, there more debris is there. Already there have been some satellites whose loss is suspected to be due to space debris. Furthermore, the Space Shuttle Atlantis may have been struck by a very small piece of space debris. The more debris, the more this will happen. Eventually, we can expect to lose a major satellite or, worse, a manned mission due to space debris collison. So, what can we do? […]