Was the title provocative enough for you?
For the past several days headlines all over the web have read “US to shoot down satellite.”
Ok, first off, that satellite is on its way down no matter what. That would be the problem. It doesn’t actually need shot “down.”
Second, after it gets nailed by whatever our government and military, in their wisdom, decide to fire at it, the satellite is going to hopefully smash apart into a bazillion little pieces, and some of those pieces will end up going up, while others stay in orbit, so in reality we are shooting the satellite in all directions.
An accurate, and still fantastic, headline should read, “US plans to blast satellite into little bits” or “US plans to blast satellite apart.”
The only reason this is happening is to guarantee that the satellite is in tiny enough pieces as it comes through the atmosphere that nothing makes it through intact. This is a dangerous thing to do because bad aim could knock it in unpredictable ways that lead to much badness (for instance, a glancing blow with failure to detonate could set the thing spinning and put it on a new orbital path that hits Earth sooner). Alternatively, we could blast it into a bunch of tiny pieces and a few big ones that wreck havoc either on Earth or in space. It’s not like Earth’s orbit really needs more space junk, but… More space junk is better than toxic chemicals killing a bunch of people on Earth. This is probably the best thing to do, and the best thing isn’t always a safe thing.
Bottomline: Weather willing the US will be blasting apart a satellite somewhere over the Pacific nearish Hawaii during the darkest part of the lunar eclipse tonight (so they can better see falling chunks – this has a good scientific reason). We are not shooting it down. It’s already on its way down. They’re just skeet shooting a really large metal pigeon filled with poison.
Want to learn more about the satellite (USA 193, for those wanting to know)? Check out Phil’s Bad Astronomy Blog. He’s got a video that gets into all the details.