[ExI] new heavy lifter
spike66 at att.net
Wed Apr 6 20:00:23 UTC 2011
From: extropy-chat-bounces at lists.extropy.org
[mailto:extropy-chat-bounces at lists.extropy.org] On Behalf Of John Clark
Subject: Re: [ExI] new heavy lifter
On Apr 5, 2011, at 2:10 PM, spike wrote:
>.I often hear the comment that the space shuttle's capability was
exaggerated (30 tons to LEO, 12 tons return.) It never came close to
either, but it was *theoretically* capable of both of these goals in its
>.Originally we were told that a Space Shuttle would have a turnaround time
of only 2 weeks and could make 25 trips a year, but they were lucky to get 3
trips a year. Originally we were told the probability of catastrophic
failure was astronomically unlikely, but the true figure was about 2% per
flight. Originally we were told that because its reusable the cost of
putting something into orbit would drop by many orders of magnitude, but
we'd have done better if we never heard of the shuttle and just kept on
making Saturn 5's. John K Clark
John I agree the shuttle program was a long term catastrophe for the US
space program. Do let us make sure we are whooping the right dog. Those
numbers you cited were for a different set of assumptions. NASA made some
decisions in the 1970s during the shuttle design and build phase that made
it clear they were sacrificing some of those end goals, long before the
shuttles flew. During the design phase, and after a lot of the hype had
already been printed in hard copy, they defunded a lot of the stuff that
would have contributed to faster turnaround and long term performance.
After the first transport to Cape Canaveral aboard a B747, it was already
clear the shuttle would achieve nothing like a 2 week turnaround. That was
on 10 April 1979. I remember that day as clearly as any from that entire
decade. I was there when the aircraft landed at Cape Canaveral. That was
the oddest mixture of elation and disappointment, I have a hard time even
describing it, but I will try.
Many of the tiles failed during the 10 April flight and fell off. I was an
engineering student at the University of Central Florida then, so you can
imagine the hot topic of conversation. We knew enough about re-entry
systems to know that if any of the tiles came off the critical surfaces
(pretty much anything on the bottom side) during re-entry, the aerodynamic
load would be transferred to the tile behind the failed one, and it too
would fail within seconds, then the one behind that, in what came to be
called the zipper effect. Row of tiles come off, front to back, wing rips
off, result: loss of vehicle and crew. We saw an example of that on 16
January 2003. Most were surprised when Challenger exploded on liftoff in
1986, but few were surprised by Columbia's break up on reentry in 2003. We
knew that could happen.
Back in 1979, a lot of the smart guys realized the existing thermal
protection system would need to be redone. I knew this because I was
acquainted with many of these smart guys, including my girlfriend's father.
He had crystal foresight: NASA would end up redoing the tiles, payload
capacity would go way down, turnaround time would go way up, costs would go
thru an already very high roof. All this was well known by summer of 1979,
two years before first flight.
There was a strong contingency arguing at the time to scrap the damn thing
and restart the Saturn V program. There were already credible voices
arguing that we couldn't rebuild a Saturn V at that time. I was there,
heard it, saw it, believed it, still do.
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