Falling Satellites and orbiting Space Junk

Look out below!

This is a great video.  Despite the enthusiastic introduction, where it describes the pieces shrieking to the earth, it does give some perspective: about one satellite a year falls to the Earth, and even with the UARS satellite not having fuel to control its descent, you have about a one in 3600 chance of getting hit. They expect about 26 pieces, the largest being around 300 pounds, to make it through the atmosphere--but it's all guesswork at this point. (My friend is actually hoping her house gets hit--she's mightily sick of her dilapidated house.  Can you imagine trying to convince your insurance that "satellite impact" is covered under your homeowners?)

Hyuk hyuk.  I just sold her the satellite impact policy.  What a maroon!

Because the satellite has no fuel left, it can't control its descent, and no one's quite sure where it will come down, so take an umbrella with you on the 23rd just in case.  (And have your cell phone camera charged!)

Anyway, this is a good time to address the issue of Space Junk.  Spcce junk is a pretty simple concept:  we lunch stuff into orbit, and not all of it comes back to earth or goes out into space.  Not only is the useful stuff up there, but the defunct stuff (satellites like the UARS that run out of fuel or malfunction); broken bits from collissions, even little flecks of stuff.

It's all potentially bad news.  Size is not as much an issue when you're traveling 17,000 mph. Back in the 80s, pea sized paint chip once impacted the windshield of the space shuttle.  It put a gouge in it.  During the last flight of the shuttle Atlantis, the ISS was in danger of being hit by a piece of a broken Soviet satellite--the docking of the Atlantis nudged the station just enough for a miss.  Even when lives are not threatened, satellites still have to maneuver at times to avoid junk.  Spacecraft ofteh have multiple layers of thin aluminum shielding.  It actually works better than a thick piece of metal.

So how much is out there?  According to NASA scientist Nicholas Johnson, there are roughly 22,000 objects bigger than 4 inches (some as big as car-sized rocket boosters weighing 9 tons), and perhaps 500,000 smaller ones, down to 0.4 inches across, in orbit.  (taken from USA TODAY--definitely go check this article out.)


Here's what it looks like in space.  Keep in mind that the dots are not to scale and space, as the Hitchhiker's Guide to the Galaxy says, "is big. Really big. You just won't believe how vastly, hugely, mindbogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space..."  However, as we add more stuff and stuff bumps into stuff and stuff breaks into smaller stuff and well, stuff happens, this will become an even more serious problem.

So what are we doing about it?  That's another blog.