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From: throopw@dg_rtp.UUCP (Wayne Throop)
Newsgroups: net.space
Subject: Re: Asynchronous orbital skyhooks
Message-ID: <82@dg_rtp.UUCP>
Date: Tue, 7-Jan-86 12:19:45 EST
Article-I.D.: dg_rtp.82
Posted: Tue Jan  7 12:19:45 1986
Date-Received: Thu, 9-Jan-86 05:34:36 EST
References: <8512312026.AA15784@s1-b.arpa> <70@dg_rtp.UUCP> <1274@sdcsvax.UUCP>
Lines: 42
Keywords: skyhook, tether

>	Question: Why wouldn't an asynchronous skyhook allow a
>	high-flying air-breather (or detachable part thereof) to be
>	injected into LEO?

> Answer: A familiar scenario from previous articles on asynchronous skyhooks
> is a rendezvous between a 747 carrying a cargo module piggyback, and
> a tether.

I think the tether/skyhook in the subsonic scenario would have to be
beyond current engineering practice.  My intent here was to ask if it
was feasible with an asynchronous currently-designable skyhook (say, of
Kevlar) to boost a cargo into LEO without using a ground catapult or any
non-reusable reaction thrusters.  This seems to imply a hypersonic
transport of some sort, since the best delta-v from the skyhook won't
boost from the near-standstill of a 747 to orbit.

Note also that the investment in the hypersonic transport development
would be swamped by the skyhook development costs (or so I suppose).  I
agree that it would be less costly to use the skyhook for the entire
delta-v, but this (as far as I know) just can't be done yet.  I was
proposing a hybrid system to "get our feet wet" with skyhook technology.

So let me rephrase.  Is it possible with 198x technology to get to LEO
using a totally reusable booster and an asynchronous skyhook, and would
this be cheaper than using disposable or partly disposable reaction
boosters.  In essence this question rests on three issues:

    Can enough delta-v be supplied by a skyhook to make a
    nearly-off-the-shelf (and completely reusable) transport workable?

    Can some plausible and nearly-off-the-shelf station-keeping
    mechanism for this skyhook deal with atmospheric drag, at reasonable
    traffic densities?

    Will the money needed to get the skyhook in orbit and the transport
    designed and built be plausibly fundable, either governmentally or
    privately?

These questions are left as an excersize for the interested reader :-).
-- 
Wayne Throop at Data General, RTP, NC
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