[meteorite-list] DoD To Engage Decaying Satellite

[Chris Peterson]

I think you are largely correct that the safety of people on the ground 
is a minor component of the decision to fragment this satellite. That 
said, however, the behavior of decaying space debris isn't all that 
different from the behavior of a meteor. Just as the interior of a 
meteorite isn't significantly heated during its passage through the 
atmosphere, the interior of debris need not reach high temperatures 
during decay. We know nothing about the location of the fuel tank in 
this satellite, but if it's buried inside, I think it is at least 
possible it could survive to the ground intact.

I recall that nematodes for biological experiments aboard the Columbia 
shuttle survived reentry.

Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


----- Original Message ----- 
From: "Francis Graham" <francisgraham at rocketmail.com>
To: <meteorite-list at meteoritecentral.com>
Sent: Saturday, February 16, 2008 1:51 PM
Subject: Re: [meteorite-list] DoD To Engage Decaying Satellite


>  There is just something not right about the
> assumptions in this press release; take it from an old
> amateur rocket man.
>  Hydrazine boils at 114 Celsius. If the tank
> containing it re-enters, it is almost certain to heat
> up and boil the material, overpressure the tank and
> explode long before reaching the ground.
>  If a fissure develops in the tank, and hydrazine is
> exposed to the oxygen in the air, even in the
> stratosphere, it will blow up at just above body
> temperature, 37 Celsius.
>  The chances of any hydrazine reaching the ground,
> and spilling out after impact, is zero I would think.
> It's not really a credible danger.
>  There may be other perfectly valid reasons why the
> DoD might want to destroy this satellite. Target
> practice is one. And there may be perfectly good
> reasons why they might not want souvenir hunters
> picking over the wreckage if it lands. It's a
> top-secret spy satellite, after all. Photos of the
> wreckage could be used to understand surveillance
> limitations and abilities. This is something the North
> Koreans probably would like to know. These are very
> good reasons for asking the public to stay clear.
>  But hydrazine after re-entry? No, I don't think so.
>  I realize I'm a bit controversial on this. So if any
> of you folks want to point out why I could be wrong,
> please do. But I think that hydrazine simply would not
> survive re-entry.
>
> Francis Graham