Ball Lightning
Feb 20, 2008, 08:12 PM
This always seemed a bit fishy, what do you think?
Link (http://www.newscientist.com/blog/space/)
Is the peril of a tank full of hydrazine the whole story behind the Pentagon's decision to shoot down a defunct spy satellite, which could occur as early as Wednesday night? Probably not, but you really wouldn't want it dropped in your yard anyway.
Like its chemical cousin ammonia, hydrazine can cause lung damage, but a whiff of it won't kill you on the spot. It's also corrosive, dissolves hair, and can do nasty things to your skin. The rocket fuel can also ignite when it makes contact with rusty surfaces, earth, wood, or cloth.
But if you spill a little of the stuff on most surfaces, after a day or so it will go away if it's outdoors or if you open the doors and windows. A modest spill outdoors won't create a long-term toxic waste site requiring a cleanup crew in moon suits, although spills of large amounts or indoors could be a different matter.
And that's the problem - the falling satellite's tank contains about half a tonne of frozen hydrazine. If the satellite were allowed to simply fall on its own to Earth, military and NASA officials expect the full tank to survive the fall and hit the Earth's surface. That's because a hydrazine tank from the space shuttle Columbia made it all the way to the ground after the shuttle broke up over Texas. Fortunately, the Columbia tank was nearly empty, but the spysat's tank could disgorge its hazardous contents over an area as large as two football fields.
Even so, the risk that the hydrazine would actually spill in your yard - or for that matter in the Pentagon's inner courtyard - is miniscule. But President George W Bush says he doesn't want to take that chance.
The Pentagon and NASA figure they might as well take a shot at the satellite - as NASA chief Mike Griffin (pictured, far right) said last week, missing the satellite completely or just denting it wouldn't make matters worse - at least in terms of a hydrazine spill.
Pentagon officials say the satellite makes a tough target for its interceptors, which were designed to hit much hotter targets - nuclear missiles. But that claim may be intended to reduce expectations. If the Pentagon sounded too confident, missing the target could very well make the US a laughing stock in the eyes of the world.
After all, China shot down one of its own satellites last year using relatively simple technology. Most saw that move as a warning to the US, whose controversial global missile defence system depends on satellites - including the ubiquitous GPS network.
Just last week, China and Russia backed a treaty banning space weapons, though the US has said such pacts would prevent it from handling any future threats to its space assets.
Is the latest decision to shoot down the falling spy satellite a demonstration that the country can and will defend those assets if the need arises? Or is the Pentagon's itchy trigger finger coming from a desire, shared by the automated systems on Magrathea, to "take the occasional pot shot to relieve the monotony"?
Jeff Hecht, contributor
Link (http://www.newscientist.com/blog/space/)
Is the peril of a tank full of hydrazine the whole story behind the Pentagon's decision to shoot down a defunct spy satellite, which could occur as early as Wednesday night? Probably not, but you really wouldn't want it dropped in your yard anyway.
Like its chemical cousin ammonia, hydrazine can cause lung damage, but a whiff of it won't kill you on the spot. It's also corrosive, dissolves hair, and can do nasty things to your skin. The rocket fuel can also ignite when it makes contact with rusty surfaces, earth, wood, or cloth.
But if you spill a little of the stuff on most surfaces, after a day or so it will go away if it's outdoors or if you open the doors and windows. A modest spill outdoors won't create a long-term toxic waste site requiring a cleanup crew in moon suits, although spills of large amounts or indoors could be a different matter.
And that's the problem - the falling satellite's tank contains about half a tonne of frozen hydrazine. If the satellite were allowed to simply fall on its own to Earth, military and NASA officials expect the full tank to survive the fall and hit the Earth's surface. That's because a hydrazine tank from the space shuttle Columbia made it all the way to the ground after the shuttle broke up over Texas. Fortunately, the Columbia tank was nearly empty, but the spysat's tank could disgorge its hazardous contents over an area as large as two football fields.
Even so, the risk that the hydrazine would actually spill in your yard - or for that matter in the Pentagon's inner courtyard - is miniscule. But President George W Bush says he doesn't want to take that chance.
The Pentagon and NASA figure they might as well take a shot at the satellite - as NASA chief Mike Griffin (pictured, far right) said last week, missing the satellite completely or just denting it wouldn't make matters worse - at least in terms of a hydrazine spill.
Pentagon officials say the satellite makes a tough target for its interceptors, which were designed to hit much hotter targets - nuclear missiles. But that claim may be intended to reduce expectations. If the Pentagon sounded too confident, missing the target could very well make the US a laughing stock in the eyes of the world.
After all, China shot down one of its own satellites last year using relatively simple technology. Most saw that move as a warning to the US, whose controversial global missile defence system depends on satellites - including the ubiquitous GPS network.
Just last week, China and Russia backed a treaty banning space weapons, though the US has said such pacts would prevent it from handling any future threats to its space assets.
Is the latest decision to shoot down the falling spy satellite a demonstration that the country can and will defend those assets if the need arises? Or is the Pentagon's itchy trigger finger coming from a desire, shared by the automated systems on Magrathea, to "take the occasional pot shot to relieve the monotony"?
Jeff Hecht, contributor