Re: Mars mission vs. spare parts

In
Message-ID:<1180205578.561853.210680@xxxxxxxxxxxxxxxxxxxxxxxxxxx>,
balpao@xxxxxxxxx wrote:

As a title I'd like the possible solution of the problem:

"Redundancy"

During first Columbus voyage Santa Maria ran aground. It was the
largest of the three ships used for the trip but they were still able
to return home and tell what they found.

Columbus also almost ran out of provisions, and topped off
his larder in the New World. That's not likely to happen on any
space mission.

Multiple failures despite multiple levels of redundancy on all the
spacecrafts of a little fleet could be nice for a plot.

You're right that multiple redundancy is needed. But there
are a lot of problems with redundancy. Among them (offhand):

size
mass
choice (how many of what)
cost
skill to replace
balance (as things are used up)
parallel deterioration (if the elastic goes, might the
replacement also have bad elastic?)

On that last point: IIRC, Apollo missions used 3 computers,
one of which was a different brand and, therefore, had different
programming. This was to guard against some factor causing all of
brand A to fail.

And remember that redundancy must include personnel.

By the way, I think a mission to Mars before we have a cheap access to
the space is a waste of money and time that could be better used for
scientific rearch, robotic missions and, most important of all,
developing a cheap access to the space :-)

I agree. Fortunately, we now have multiple private companies
exploring new spacecraft techniques and new funding schemes.

--
Arthur T. - ar23hur "at" intergate "dot" com
Looking for a z/OS (IBM mainframe) systems programmer position
.