🚀 go-pugleaf

Like I said in the original post, I don't want the "How to Explore
Mars" thread to be about reliability; I have therefore started a new
thread to continue the discussion about reliability.

[I don't speak for the Erebus project; the following are my opinions.]
The Erebus project was not intended to explore reliability, so few
conclusions about reliability should be drawn from it.  That Dante
failed at a single point of failure should not be surprising, given
that a fault-tolerant design was not a goal.  Goals must be limited in
every experimental situation.  The main goal of the Erebus was to test
robotic technologies in a real environment; reliability was not a big
concern since people would be there, and so reliability did not need
to be included as a major goal of the project.

gat@forsight2.jpl.nasa.gov (Erann Gat) writes:
>
>That using multiple small robots increases realiability is not a "naive
>assumption", it is a theoretically and empirically verifiable fact.  It
>does not matter whether failure modes are independent.  Unless there is
>100% correlation among failures in multiple units (which is never the case)
>having more units will increase the overall system reliability.

This is a simplistic statement, which would lead to a hot debate if
made in comp.risks (where it would be phrased "Four engine airplanes
are obviously safer than two engine airplanes, so why aren't there
more of them?").  Two factors this statement ignores are complexity,
and how to maximize reliability while minimizing cost.  Redundancy is
a very important technique for creating reliable systems, but "mere
redundancy" is *not* enough; it is a lot harder than that.  Food for
thought: multiple robot systems already have the very hard problem of
constructive interaction; might this complicate reliability even more?

[begin personal discussion]

gat@forsight2.jpl.nasa.gov (Erann Gat) also writes:
>...
>You know Jerry, I'm really happy when you shoot your mouth off like this
>because it makes me look diplomatic by comparison.
>...
>There you have it, folks: Jerry Roston cannot think of a solution to
>the telemetry problem, ergo it is impossible to solve.

Why are you being so nasty?  If you have a bone to pick with someone,
do it by email; the rest of us are not interested.

[end personal discussion]

- John
--
hagerman@ece.cmu.edu