[AR] Re: Falcon 9 flight today
- From: Henry Spencer <henry@xxxxxxxxxxxxxxx>
- To: Arocket List <arocket@xxxxxxxxxxxxx>
- Date: Tue, 8 Oct 2013 13:06:04 -0400 (EDT)
On Mon, 7 Oct 2013 JMKrell@xxxxxxx wrote:
> Henry notes that most of the venting is LOX. Ionizing radiation quickly
> converts oxygen to monatomic radicals. Monatomic oxygen does etch the
> surfaces of satellites as they pass through the cloud...
Note, though, that there is plenty of atomic oxygen already present in
LEO. And it will take time for solar UV to split up many of the oxygen
molecules, time in which the cloud will be expanding rapidly. This isn't
likely to be a significant hazard.
> The pressurizing gas in the RP-1 tanks is vented, but little RP-1.
The vapor pressure of RP-1 isn't large by Earth standards, but it's still
substantial by vacuum standards. The RP-1 won't stay in the tank,
although it may leave a bit of residue behind.
> Venting tons of RP-1 would pose a coating hazard to satellite optics and
> sensors.
Again, this sort of thing would be an issue only if the satellite passed
very close to the venting stage, very soon after the venting started.
The density of the vapor/crystal cloud just isn't high enough to be
an issue otherwise. People vent RP-1 stages in orbit all the time; I
don't believe any satellite problem has ever been attributed to this.
Henry Spencer
henry@xxxxxxxxxxxxxxx
(hspencer@xxxxxxxxxxxxx)
(regexpguy@xxxxxxxxx)
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