Newsgroups: sci.space.shuttle
From: henry@spsystems.net (Henry Spencer)
Subject: Re: SRB economics (was Re: Heat proof ET)
Date: Sun, 29 Oct 2000 03:19:38 GMT

In article <Pine.BSO.4.21.0010281614350.24508-100000@shell.pacifier.com>,
Tracy  <vagabond@pacifier.com> wrote:
>I think that making new ones would be a little more, consider all the
>factories, materials, and labor to make them.  The NAVY picks the SRBs up,
>so you can consider that training.  The labor and material to refab the
>SRBs would be lots cheaper...

As others have noted, the SRB pickup is done by NASA and its contractors,
not by the Navy.  As for relative costs, the SRBs basically have to be
dismantled very nearly down to the component level, and then everything
gets checked, tested, reassembled, and inspected -- it is *not* much
cheaper than building the thing in the first place, because much of the
same work has to be done.
--
Microsoft shouldn't be broken up.       |  Henry Spencer   henry@spsystems.net
It should be shut down.  -- Phil Agre   |      (aka henry@zoo.toronto.edu)

Newsgroups: sci.space.shuttle
From: henry@spsystems.net (Henry Spencer)
Subject: Re: SRB economics (was Re: Heat proof ET)
Date: Sun, 29 Oct 2000 20:20:52 GMT

In article <Pine.BSO.4.21.0010290845130.30229-100000@shell.pacifier.com>,
Tracy  <vagabond@pacifier.com> wrote:
>> ...As for relative costs, the SRBs basically have to be
>> dismantled very nearly down to the component level, and then everything
>> gets checked, tested, reassembled, and inspected -- it is *not* much
>> cheaper than building the thing in the first place, because much of the
>> same work has to be done.
>
>	...one would think that the cost
>savings from not having to manufacture the new parts would be
>enough.  (Give the cost of the materials, labor, testing and all).

The materials cost is fairly insignificant, and much of the labor goes
into checking and testing... which has to be done all over again during
refurbishment, given what the SRB has been through.  (Being dunked in
seawater is particularly bad for the on-board equipment.)

--
Microsoft shouldn't be broken up.       |  Henry Spencer   henry@spsystems.net
It should be shut down.  -- Phil Agre   |      (aka henry@zoo.toronto.edu)

Newsgroups: sci.space.shuttle
From: henry@spsystems.net (Henry Spencer)
Subject: Re: SRB economics (was Re: Heat proof ET)
Date: Mon, 30 Oct 2000 15:02:45 GMT

In article <39fcfe92.7686552@news.virginia.edu>,
Chris Manteuffel <cdm7g*REMOVETHIS*@virginia.edu> wrote:
>>...SRB refurbishment is more for PR
>>than for actual cost savings; it involves far too much work to be very
>>cost-effective.
>
>Original plans for the STS called for a reusable flyback booster that
>would carry a crew of two. Those were canned because of the tremendous
>development cost... but would the same considerations that apply to the
>SRB's apply to this hypothetical booster?

It would see a somewhat less severe environment, e.g. no dip in seawater
at the end of the flight.  I think the key question would be how it was
designed and operated.  A robust design with plenty of margin, operated
sensibly, could easily be not much more expensive to fly than an aircraft.
A bigger version of today's shuttle orbiter would be another story, quite
possibly uncompetitive with a simple expendable design.

There was consideration of a number of intermediate possibilities, by the
way:  reusable variants of Saturn stages, splashdown-recovered liquid
boosters, expendable pressure-fed liquids, etc.  All lost out to solids on
grounds of development costs.
--
Microsoft shouldn't be broken up.       |  Henry Spencer   henry@spsystems.net
It should be shut down.  -- Phil Agre   |      (aka henry@zoo.toronto.edu)