QUESTION:
Why does the environmnent around the Surveror have to be so very, very 
clean.

ANSWER from Charles Whetsel on March 29, 1997:
One of the leading causes of spacecraft failure is called "foreign object
contamination" which is a fancy way of saying "dirt where it shouldn't be."
In space, it is very easy for small pieces of contamination to find their
way into both electrical and mechanical assemblies where they can either
cause an electrical short ciruit or grinding against moving parts.  Most
aerospace (and a lot of high-tech electronics) manufacturing and assembly
takes place in very tightly controlled "clean rooms" where all of the
engineers and technicians must wear "bunny suits."

Charles Whetsel
Chief Project Engineer
Mars Surveyor Operations