[AR] Re: SSTO
- From: Henry Vanderbilt <hvanderbilt@xxxxxxxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Mon, 12 Feb 2018 12:04:10 -0700
On 2/12/2018 2:23 AM, Uwe Klein wrote:
Am 12.02.2018 um 04:33 schrieb Henry Vanderbilt:
To amplify a bit, faster-than-1-day turnaround tends to push toward
having a single vehicle returning directly to the actual launch site.
SSTO can do that, at cost of some increased propellant-per-payload-mass
consumption.
If you reach orbit you have full resource invariant choice on the
landing site, don't you? ( in scope of a reasonable start site.)
Within limits imposed by the particular orbit and the vehicle, once in
orbit you can land where you like, yes.
The vehicle limit is crossrange - the degree to which your vehicle can
laterally alter its path during reentry. Generally a matter of how much
aerodynamic lift it can develop during reentry without overheating.
(Laterally maneuvering while still in orbit, IE changing your orbital
inclination, tends to cost far too large a mass of propellant to be
routinely practical.)
The orbital limit is (since the Earth is turning under you at 15 degrees
per hour) how long will it be before a subsequent orbit will line up
closely enough with your desired landing site so that your vehicle has
enough reentry crossrange to reach it.
Typical capsule-type vehicle crossranges are in the low hundreds of
miles. Winged or lifting body vehicles can have crossrange as high as a
thousand or so miles.
Beyond that, nobody spends much effort in achieving additional
crossrange, as a thousand or so miles crossrange is generally enough to
return directly to your launch site after just one orbit.
Henry V
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