Stuf4 wrote:
As seen on this "Space Shuttle Program Development Roadmap":

http://spaceflight.nasa.gov/shuttle/...es/roadmap.pdf

...the number 1 goal of shuttle upgrades was "Fly Safely", and the
very first safety upgrade on this schedule was the MMOD/WLE fix which
was to strengthen the Wing Leading Edge RCC panels.

This one slide gives an excellent snapshot of upgrade priorities circa
1997.

(Obviously, these priorities were subsequently rearranged.)


~ CT

Also, the National Research Council was commissioned to report on NASA's
methods of selecting upgrades to the shuttle. For their assessment of
individual upgrades, see
http://www.nap.edu/html/upgrading/ch4.htm
published by the National Academy Press. Among others, they talk about
MMOD upgrades and avionics upgrades. Again, Safety is the number 1
criterion for selecting upgrades. Earlier in the document, you can find
more details on the upgrades selection process and how the board functions.

-stmx3