According to this article one of the objects found floating around the space shuttle is a plastic bag. I’m not interested in speculating how it got outside the shuttle because that will just lead me to making a series of jokes but I do have one serious question.
What is the effect of near 0k temperatures and of radiation on a plastic bag?
Does it become stiff from the cold or does the radiation break it down and melt it, so to speak?
Also, I can clearly understand how a stray bolt can cause some serious damage to the shuttle but how much of a threat does a plastic bag pose for the shuttle?
I saw a photo of a cracked shuttle window that had been broken by a fast-moving paint flake - a plastic bag moving at similar relative speed is going to do a great deal of damage to whatever it hits.
Dunno about effects on the bag though - it’s only going to get cold if it’s in the shade; space isn’t cold; it doesn’t have any ambient temperature at all and vacuum is a great insulator. Assuming it’s a polythene bag(which it probably isn’t), exposure to ultraviolet radiation from the sun is going to degrade the plastic quite quickly, turning it opaque and brittle.
It could be a bag for storing things. There are lots of possibilities.
Plastic in high-energy )radiation) environments have bonds broken and re-linked, generally cross-linking them. A little of this is good, making the plastic tougher and less likely to break. But if it gets too muxch it becomes brittle. Plastic in the vacuum of space will also lose its volatile components, mainly plasticizers that keep it pliant and supple. So the twin effects of vacuum and radiation are to make the plastic more brittle. There isn’t much to break it in space, in zero G. But, after a time in space, if it encounters anything at all, I suspect it might come apart. (The “cold” won’t do much. It’s not “cold” in space, there being no atmosphere to convey cold. In fact, between the energy being received from the sun and the blackbody radiation emanated into space, an object is, on average, not that far from 300 K. Of course, one side is getrting all the radiation and the other is doing all the radiating, so the temperature is going to be not equally distributed, unless the object’s rotating.) The plastic bag isn’t going to melt.
As for the damage a plastic bag can do – it can be pretty impressive if it has a huge velocity relative to you. With no atmosphere to retard it, there’s no drag and no terminal velocity, so your instinct and experience misinform you about how much damage it can do. There have been craters (microcraters, to be sure, but craters nonetheless) put into spacecraft windows by what were believed to be paint chips with high relative velocities. Considered in that light, an entire plastic bag can wreak havoc if it hits something fast enough.
We keep getting told that space junk is a problem, but this particular piece of space junk really brings it home for me. It’s just so sad. There are plastic bags in our oceans, our deserts, our wetlands, our mountain ranges, and now in bloody space…
Before he died, Daniel O. Graham (the same one, I believe, who proposed the “High Frontier” spacecdefense concept, even before Reagan’s “Star Wars” speech) wrote a science fiction novel entitled “The Gatekeepers”, in which a grouop threatens to deny space travel to all competitors (and itself, for that matter) by releasing a huge quantity of ball bearings into orbit at high speeds in random directions.
In his book Science Made Stupid, Tom Weller had a drawing of orbital debris. It consisted of lost socks, lost car keys, loose change, and other random junk.
But my understanding is that socks are actually the larval form of coat hangers.
I am not sure if this worthy of a seperate thread, but how does a plastic bag get into space? Forgive me for my ignorance which I am in recovery for now.
Is it from the space station or trash dumping for space shuttles? Could it somehow leave Earth and ‘get up there’?
Does anyone remember the Lost is Space episode where the crew of the Jupiter II were put on trial for space crimes because a wrench was lost during a space repair?
This isn’t the first time that something odd has floated free from a spacecraft. On one of the Gemini space walks, a glove floated out of the cabin. To this day, no one knows who’s glove it was, or how it got there. It could have been left in the cargo bay by someone at nearly any point. The ISS has two ways of getting rid of it’s garbage. One is to load up the space shuttle when it docks there, the other is to load it into a Progress cargo ship after they’ve unloaded it. AFAIK, the only stuff that the ISS or shuttle dumps into space is urine.
