Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!haven!uvaarpa!mcnc!thorin!lhotse!symon
From: symon@lhotse.cs.unc.edu (James Symon)
Newsgroups: sci.space
Subject: Re: Sanger
Message-ID: <7284@thorin.cs.unc.edu>
Date: 16 Mar 89 15:36:24 GMT
References: <1989Mar14.172237.29235@cs.rochester.edu <7234@thorin.cs.unc.edu> <78@enuxha.eas.asu.edu>
Sender: news@thorin.cs.unc.edu
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In article <78@enuxha.eas.asu.edu>, kluksdah@enuxha.eas.asu.edu (Norman C. Kluksdahl) writes:
> I have done some back-of-the-envelope calculations to check out the
> advantages of speed at release of the orbital vehicle.  (Note:  these
> are only rough calculations, intended only to demonstrate a point).
> 
> In all cases, it is assumed that the payload is released at an altitude
> sufficiently large to neglect most air frictional effects.  . . .

You don't mention the mass ratio for standing start at sea level
(considered common knowledge I suppose, but I'm just a voyeur) but
your numbers suggest to my envelope-back that the benefits of added
speed at launch probably don't warrant the investment in a Mach 5
launch vehicle.

> . . .  Still, air launch does promise something--I read that OSC's
> Pegasus gains about 15% in usable payload by air launch at Mach 0.8. 

And that's still down in pretty thick air, isn't it? So how about Mach 0.0 
at 125,000 ft. under a set of monster balloons?

jim
symon@cs.unc.edu
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