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From: dietz@SLB-DOLL.CSNET (Paul Dietz)
Newsgroups: net.space
Subject: Re: Re: Side comment on the disaster
Message-ID: <8603021937.AA03467@s1-b.arpa>
Date: Sun, 2-Mar-86 12:29:23 EST
Article-I.D.: s1-b.8603021937.AA03467
Posted: Sun Mar  2 12:29:23 1986
Date-Received: Tue, 4-Mar-86 01:47:16 EST
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[debate between E. M. Smith and Bill Sebok on reusuability and size of
  launchers]

There are additional advantages to small launchers.  Generically,
building a small ANYTHING is a good way to get experience before
building a large economy-sized model.  Small jets were built before
747s.  Small rockets were launched before the Saturns.  It's
generally easier to try out competing technologies at the prototype
stage.  The motto "plan to throw one away, you will anyway" applies
to any complex system, not just to software.

>   Reusability is a critical issue because
>   it is tied so closely to cost.

One of the shuttle's problems is that it's not really reusable.
The ET gets thrown away ($40 million (?) right there).  The SRB's
require extensive refurbishment.  The tiles need to be inspected.
The main engines require constant maintenance and rebuilding.
I'd like to see hard numbers on the number of man-years of effort
needed for one shuttle flight vs. a similar number for one expendable
flight (including the effort in building the shuttle, amortized, and
the effort in building the expendable booster).  I expect the ratio
is quite small.