>> Ha! I have heard that before... Cost and availability? Maybe...
>> Superior
>> Safety? Never!

> Unless you have some figures to back that up, it sounds like an
> emotional
> knee jerk statement to me.  I don't know if the shuttle is in fact
> safer
> than other alternatives, but it's far from obvious that it's not.

Given the rather small sample size in statistical terms, the Shuttle
is about as safe as other systems. It may in reality be less or more
safe but the data set is too small to know with certainty. Apollo
managed to kill 3 men on the ground, and that was systems failure
every bit as much as was the loss of the two Shuttles - and if
anything more "stupid" and more predictable with 20/20 hindsight
(sadly). Apollo 13 tried very hard indeed to kill another 3 - which
would have made Shuttle safer.

One point to note is that it can make more sense to measure fatalities
in terms of vehicle losses or incidents involving fatalities. This
allows sensible comparison of losses for single person and eg 20
person spacecraft. It is reasonable to compare the loss of a 7 person
Shuttle to that of a 3 person Apollo or Soyuz.

There have been about 450 person-flights into space. There have been
22 deaths "in spacecraft". 1 in an X15 (X15-3 uncontrollable spin on
descent and subsequent in flight breakup), 3 in Apollo 1 (pad fire due
to pure Oxygen atmosphere at full atmospheric pressure (!)), 1 in
Soyuz 1 (parachute malfunction due to design error)*, 3 in Soyuz 11
(depresssurisation during re-entry), and 7 each in Challenger and
Columbia. * Soyuz 2 was a lucky save - it was have to been orbited in
conjunction with Soyuz 1 but circumstances prevented the launch. It
was subsequently found to suffer from the same fatal design error as
Soyuz 1.

All spaceflight to date pushes the state of the art closely enough and
involves such immense energy levels that death is never avoidable with
certainty. One can reasonably expect that NASA will try extremely hard
to improve safety and overcome the types of organisational (rather
than engineering) problems which caused the loss of both Shuttles to
date.



        Russell McMahon






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