[AR] Re: Air Launch Reference
- From: Bill Claybaugh <wclaybaugh2@xxxxxxxxxx>
- To: "arocket@xxxxxxxxxxxxx" <arocket@xxxxxxxxxxxxx>
- Date: Mon, 16 Feb 2015 05:18:32 -0500
Liam:
I do not know of any reference but here are some general observations:
- in general, air launch is more expensive than ground launch (I know Burt says
the opposite, but he is provably wrong).
- if custom built; air launch drop aircraft are typically more costly than a
ground launch pad for the same size solid rocket.
- annual O&M costs to maintain flight certification are typically higher than
the same costs for a solid rocket ground launch pad.
- horizontal drop requires a pull-up maneuver; the lowest mass way to do that
is wings, but all that mass is unneeded for ground launch. The alternative is
to have the drop aircraft pitch up; that requires a much higher performance
aircraft.
- air launch rockets want to be solids, particularly if horizontally launched.
Feed system complexity and slosh issues during the pull-up add still more mass
to a liquid solution which is not offset by the increased Isp.
- most of the additional performance from air launch is in the higher area
ratio of the first stage motor; the velocity imparted by the aircraft is
trivial in comparison.
- to make air launch economically competitive the aircraft has to have some
other user (e.g. sub-orbital joyrides; carrying large or bulky cargo);
otherwise the O&M cost quickly drives the project to the high cost, low flight
rate corner of the box (Pegasus, for example).
- the advantages of "any orbit; any time" are largely national security
related; in the absence of such a sponsor / customer there is very little
commercial justification for the higher cost of air launch. Cheaper to wait
for the desired orbit to pass over the launch pad. (Which, BTW, argues for a
single, all azimuth, ground launch pad.)
Bill
Sent from my iPhone
On Feb 14, 2015, at 12:38 AM, Liam McQuellin <lmcquellin@xxxxxxxxxxx> wrote:
> Hi All,
>
> I am writing a paper and I am looking for a text book that describes air
> launch concepts. Does anyone know of any they could recommend?
>
> Thanks,
>
> Liam McQuellin
> Australian Space Research Institute
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