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From: al@vger.UUCP ( Informatix)
Newsgroups: net.space
Subject: Re: space plane
Message-ID: <352@vger.UUCP>
Date: Mon, 24-Feb-86 20:31:12 EST
Article-I.D.: vger.352
Posted: Mon Feb 24 20:31:12 1986
Date-Received: Fri, 28-Feb-86 01:21:07 EST
References: <8602231253.AA23756@mitre-bedford.ARPA>
Organization: UC Santa Cruz, CIS Dept.
Lines: 12

In article <8602231253.AA23756@mitre-bedford.ARPA>, jrv@MITRE-BEDFORD.ARPA (James R. Van Zandt) writes:
> I've heard that the new "space plane" is supposed to get things into
> low earth orbit at 1% of the cost of the shuttle.  Are there good reasons
> for that, or is it just hype from aerospace marketing types?

The fundamental reason is that the proposed engines (scramjets) use the
atmosphere for oxygen.  Since oxygen accounts for 8/9ths of the weight of
hydrogen/oxygen fuel, there is a dramtic weight savings (I think the
shuttle tank holds 600 TONS of oxygen - the orbiter weighs about 200 tons).
I don't know the details
of the cost estimation, but if scramjets can be made into practical
devices we should see a large decrease in cost to orbit.