Spy Satellite to Hit Earth by late February to March Options

[Guest_Bobby_*]

Just read at MSNBC that a large U.S. spy satellite will hit Earth by the end of February or early March.
Better keep our hard hats ready???

Here is the article:

http://www.msnbc.msn.com/id/22857051/

[edstrick]

"I think they are more interested in destroying secret instruments on board that could fall into the wrong hands than protecting the public. The destruction will create debris left in space, just like destruction of the Chinese Satalite. "

NASA TV carried the press conference this afternoon, 1:30 central time. NASA Admin Griffin was one of the panalists to provide info-backup and support for the 2 military briefers. They spent most of the briefing and Q&A session debunking such double-nonsense as is embedded in this quote.

Point 1: While they may be lying -- some people automatically assume the military will lie about anything as a matter of mere convenience -- they were absolutely categorical about the planned destruction of the satellite being for safety reasons, not for eliminating classified technology information.

Point 2: The debris will not be "left in space". The chinese satellite was at some 450-500 miles altitude. The satellite will be at 130 miles altitude or lower when targeted. You can do about 1 orbit at 85 miles. Mercury early missions orbited at 90 miles where you can do about a day. 130 miles up youi may last a couple weeks or so if you're large and dense.

The debris from the chinese satellite will all (except for stuff that's like dust) be in orbit for decades, up to a century or more for big chunks. It will slowly decay, passing THROUGH the most used low orbit altitudes including where all manned missions fly except lunar missions. Note that if you intercept and fragment (the phrase "shoot down" is so wrong it's "bad astronomy" bad) a sat at exactly 500 miles altitude, essentially all the fragments end up on orbits passing through that 500 mile intercept point. Some will have higher apogees, some will have lower perigees, some end up in elliptical orbits that cross through 500 miles altitude.

When you intercept and fragment a satellite at 130 miles altitude, the fragments end up in orbits passing through 130 miles. Many will have perigees lower than that and re-enter on the next orbit or in a few days. Some will still have a 130 mile perigee but have a higher apogee. They'll still re-enter in a few days, as the drag at perigee is what counts, and their mass-per-surface-area is greatly reduced, so the drag slows them faster. Essentially all the debris will be below altitudes anything normally orbits at and essentially all will re-enter in a month.

What they were extremely specific and emphatic about, including Administrator Griffin, is the hazard involving the hydrazene tank. The tank is big. 40 inches (1 meter) diameter, and full of hydrazine -- frozen hydrazine that was never used up as the satellite failed completely the first day on orbit. There's a lot that IS known about re-entry, particularly after the post Columbia studies. (I've held a small titanium tank from Columbia in my hands -- we were inspecting it for possible internal defects (existing pre-disaster) that other shuttle tanks might have.) Griffin said: The tank WILL survive entry intact. It WILL be full of hydrazine. LITTLE hydrazine will be lost due to heating and boil-off during entry. The tank will not remain sealed during entry and impact: fuel lines will be ripped from other hardware during satellite breakup. (approximate quote) It will cannonball into the ground and sit there, either cracked or intact but leaking as the hydrazine melts and evaporates. With average wind conditions, an area typically the size of 2 football stadiums will be exposed to health-endangering or lethal amounts of hydrazine fumes. They said that if it were not for the specific risk due to the tank, they would not have decided to carry out this operation.

The intercept missile is an Aegis tactical ICBM (really IRBM) interceptor. It had to be modified to carry additional propellant to extend it's range up to the 130 mile (note.. I think they were using nautical miles) altitude. Software had to be specially modified to enable the intercept of this non-warhead like target in this non-warhead like trajectory. As a camoflauged test of an anti-sat system (which the moonbats will be screaming is the purpose of the operation), it's a hell of a lousy test.

[helvick]

Excellent summary Ed - the reporting has certainly been uniformly "Bad Astronomy" bad.

While this is definitely not a useful test of true anti satellite weaponry it is almost certainly a good test of the intercept guidance systems and I would be very surprised if this exercise was not being viewed by a very useful test by the military even though I do believe that the primary reason being given is genuine. Ignoring the pure military angle it is also a useful test of an if-all-else-fails mechanism for "safely" dealing with the de-orbit of potentially hazardous debris.

The one thing that surprises me about the whole situation is that this seems to imply that there is no self destruct capability on this satellite - I know nothing about spy sats but I would have expected them to have some self destruct capability and even a small charge located on or near the main fuel tank(s) would surely be a much more practical way of safing this thing than trying to hit it with a interceptor at a couple of km/sec.

[nprev]

The one thing that surprises me about the whole situation is that this seems to imply that there is no self destruct capability on this satellite -

For all we know, it might; I get the impression that they haven't been able to talk to it for quite some time, though. (Actually, after re-reading Ed's outstanding summary, they might have NEVER made contact with it).

On the other hand, most SVs seem to get boosted into "disposal" orbits at the end of their operational lifetimes or intentionally deorbited if they're low enough, so maybe there is no self-destruct system. Doesn't really seem that you'd want to carry explosives that might accidentally destroy the vehicle, either, and you really don't want to blow it up on-orbit & tick everyone off, esp. if you're trying to keep the entire thing very low-profile in the first place...

However, no idea how the Secret Squirrel crowd handles EOL with their toys.