Firey metal from above

http://news.yahoo.com/dead-nasa-satellite-soon-plummet-earth-161801965.html

Nasa says there's a 1-in-3,200 chance of somebody on Earth getting bonked by a falling satellite later this fall. The odds of any individual getting hit are 1-in-21 trillion.

Somehow I just don't like those odds.

 

Wait until the ISS comes in someday. That'll be the time to take a vacation in a salt mine for a week or so.

 

Are you quoting a Dio song?

 

I never thought there'd be a place that would offer more racist, inane, ridiculous, hateful, spiteful, boring, poorly spelled, sexist comments than YouTube or newspaper websites.

And then I started reading Yahoo! news comments.

 

Naw, they'll drop the ISS into the Pacific on a controlled descent like the Russians did with Mir.

Skylab came down uncontrolled and we were lucky it was over the Indian Ocean and Australian outback. It could've come down anywhere, like this satellite will.

 

That assumes that when the ISS wants to come down, we have some capacity to do something about it (which currently we don't). Or we can hitch a ride with the Russians or somebody else to do so, AND that nothing happens in the interim (major on-board malfunction, debris strike) that dramatically accelerates the date that all happens. None of which, of course, we have any guarantees for.

Plus deorbiting the ISS is not going to be a simple deal. That thing is about half the size of a football field. It's got a very irregular drag profile. It's going to break into a lot of pieces and those pieces are going to fly in unexpected directions when they start hitting the atmosphere. The idea that we're just going to send up some kind of unmanned booster engine that's going to dock onto one end of it and drop it neatly in the drink -- well, I dunno.

 

The way I understand it, the ISS itself has no thrusters, but it has to be boosted to a higher orbit several times a year because of slight atmospheric drag. That can be done with the attached service module or one of the Russian Progress ships when it docks.

So basically it's orbiting on a prayer as it is, and only a few hundred meters per second of delta-V will bring it down. When it's time, it won't be difficult. Most of the solar panels and extraneous stuff will burn up on re-entry.

Now if the Russians don't figure out what's up with their rockets, it could be coming down sooner than you think ....

 

Like their airplanes, they're good at launching stuff, not so good about what comes after that.

 

The total mass of the ISS is over a million pounds.

To achieve delta-v of several hundred meters per second for the whole shebang, you'd have to bolt a Saturn V first stage to one end of it. (Not really but you'd need a pretty damn massive booster.)

The periodic altitude boosts are not a big problem because they are done very gradually, with barely-perceptible rates of acceleration to nudge the orbit a few km higher to keep it up there.

There actually is a plan:

http://www.space.com/9643-tation-disposal-plan-revealed.html


The story says it would take 9 tons of propellant to achieve the necessary delta-V. That's quite a few Progress/Soyuz ships.