QUESTION:
My question is in regard to the problem you encountered with the air bags
upon landing.  Would it be possible to make the bags out of a material that
would break down under the harsh UV rays from the sun?
 
This way, if the bags failed to retract again, the start of the mission
could be delayed until the bags colapsed and the ramps could be deployed
without problems.

ANSWER from Robert Manning on August 21, 1997:
Great idea! If only such a material that is as strong as steel and
flexible as comman thread AND quickly degradable in the Martian Sun
could be invented! Maybe it will someday. Actually the kevlar-like
material (Vectran) of the airbags will break down under the
ultra-violet light, but it will take an extrodinarily long time. 

The only "problem" we had after landing was that we had not completely
retracted the bags. This was intentional. I did not want to stall the
retraction winches during the automatic retraction process when the petals
were all closed. Stalling takes a fair bit of extra current and I was
concerned about over-taxing the battery. I also wanted to leave a little bit
of slack in the retraction cords so that the winch did not break the lines.
My goal during the automatic retraction and petal opening sequence (done
without communication with Earth by the way) was merely to get the petals
safely open. We knew all along that all we had to do was look at the
pictures and possibly reel them in a bit on the first day on Mars. And that
is exactly what we did. We added about 5 extra turns to the 42 turns already
on the winch that is attached to the airbag under the rover petal. I hope to
pull in the remaining 2 bags once the "super pan" is complete and there is
no more concern about possibly slightly moving or tilting the lander and
affecting the quality (pointing accuracy) of the image panorama taken by the
IMP.