[AR] Re: Air Launch Reference
- From: Lloyd Droppers <ldroppers@xxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Mon, 16 Feb 2015 12:37:59 -0800
Liam,
It is not a textbook, but a good place to start for air launch
information is the Pegasus User's guide
<http://cms.orbitalatk.com/SiteCollectionDocuments/Orbital%20Data%20Sheets/Pegasus_UsersGuide.pdf>.
It is the only air launch orbital launch vehicle I know abut that has been
successful and the User's guide and a fair of general information on the
air launch concept.
I also agree with Bill here in that air launch is a probably going to be
more expensive than ground launch, and that the vehicle, or at least the
first rocket stage, really wants to be a solid.
Lloyd
On Mon, Feb 16, 2015 at 2:18 AM, Bill Claybaugh <wclaybaugh2@xxxxxxxxxx>
wrote:
> 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
>
>
Other related posts: