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Re: A Few Questions



How do they use aerobraking to raise the perigee?  You pretty much have 
to burn at apogee to do that.  I suppose you could aerobrake to lower 
apogee and turn a GTO into a LEO, but that's an enormous waste of energy 
unless someone else is going out to GEO and dropping you off on the way, 
a la AO-40/PAS-1R.  Also, once you lower the perigee enough to 
aerobrake, you're probably not going to be able to raise it again 
without having some sort of secondary propulsion system to give you 
apogee kicks once you get to the right apogee altitude.

Personally, if I built a bird, I'd want to be well away from the GTO 
trajectory, because there's a lot of discarded junk -- spent upper 
stages, bits of thrust structure, SRB exhaust condensate, etc. -- on 
that road and even a paint flake hitting a LEO bird at GTO perigee 
velocity will kill it.  I'd feel much better with an actual LEO launch, 
whether it meant an STS or Soyuz ride and a hand launch or some other 
smaller booster ..

On Thursday, March 28, 2002, at 03:17 PM, Jeff Davis wrote:

> It's interesting to note that a commercial company, AeroAstro, has a 
> system
> to use a GTO ride to get to LEO by a fairly unique process of 
> aerobraking.
> Their reasoning is that there are more launches available to GTO than 
> to LEO
> and through a few manuevers (and much less fuel) they can get to where 
> they
> want to go more easily.
>
> I don't know that the amateur satellite community can get any "easier" 
> ride
> to GTO, but that kind of orbital transfer is an interesting concept that
> could open the door to MEO via GTO.
>
> 73, Jeff - N9AVG

"Oh yeah? Well, I speak LOOOOOOOUD, and I carry a BEEEEEEEger stick -- 
and I use it too!"  **whop!**   -- Yosemite Sam

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