SpaceX announces details on Falcon V

On Wed, 28 Jan 2004 06:09:28 GMT, in a place far, far away,
(Henry Spencer) made the phosphor on my monitor
glow in such a way as to indicate that:

In article ,
John Schilling wrote:
For chemical propulsion, it's never worth bothering with a tug. You wind
up carrying a substantial ammount of propellant all the way to GEO for
the sake of recovering some [relatively cheap bits of hardware]
Even with aerobraking?

Aerobraking doesn't help with the GEO deorbit burn, which is roughly
half the problem...

Somewhat less than half the problem if you're willing to go via a lunar
flyby, or just a leisurely loop up to very high altitude (where you make a
very small burn) and then back down. (Yes, it costs rather less to boost
from GEO to infinity than to drop from GEO to Earth.) Still not cheap,
though, and rather more time-consuming.

I also wonder if bi-elliptic transfers were considered in general.

In article ,
Rand Simberg wrote:
Somewhat less than half the problem if you're willing to go via a lunar
flyby, or just a leisurely loop up to very high altitude (where you make a
very small burn) and then back down. (Yes, it costs rather less to boost
from GEO to infinity than to drop from GEO to Earth.) Still not cheap,
though, and rather more time-consuming.

I also wonder if bi-elliptic transfers were considered in general.

Alas, a simple bi-elliptic transfer is a net win only if the change in
radius from initial to final orbit is at least a factor of 11.94, and LEO
to GEO is only about half that. You need either a requirement for about a
40deg plane change, or else a way (like aerobraking) to get a fair bit of
the delta-V "free" to make it a win.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

On Wed, 28 Jan 2004 19:07:46 GMT, in a place far, far away,
(Henry Spencer) made the phosphor on my monitor
glow in such a way as to indicate that:

Alas, a simple bi-elliptic transfer is a net win only if the change in
radius from initial to final orbit is at least a factor of 11.94, and LEO
to GEO is only about half that. You need either a requirement for about a
40deg plane change, or else a way (like aerobraking) to get a fair bit of
the delta-V "free" to make it a win.

I was thinking of the combination.