QUESTION:
How many experiments did you perform to tes gallilleo?

ANSWER from Charlie Sobeck on February 1, 1996:
Let me answer this questions two ways with respect to the Galileo Probe.

First, at Jupiter, the Probe conducted nine experiments, using six instruments
and some engineering hardware (specifically the Probe transmitters and radio
receivers).  The nine experiments were; an atmosphere structure experiment to
measure the temperature, pressure and Probe acceleration; a nephelometer
experiment to measure clouds; an experiment to measure the ratio of helium and
hydrogen; an experiment to measure the radiation (light) in the atmosphere; a
lightning detector; a mass spectrometer to measure what kind of molecules are
in the atmosphere; a particle detector to measure the radiation above the
atmosphere; an experiment to measure the winds on Jupiter by measuring the
Doppler shift in the transmitter frequency; and an experiment to learn about
the atmosphere by looking at how the transmitted signal is weakened by the
atmosphere.

But if you want to know how many tests we had to do on the ground in order to
build the Probe correctly, well, there were literally thousands of tests! 
Each piece had to be tested as it was built, before we built that part into a
larger one.  Then we had to test the larger part before it too was put into a
larger part yet.  Not only did we have to test that each part worked, but also
that it work under all the various conditions that it would eventually be
exposed to.  For example, we tested the Probe, then we shook it on a vibration
table to simulate the condition during the launch in the shuttle, and then we
tested it again to see that it was still working (because, of course we wanted
it to work after launch).  We tested the Probe when it was cold.  When it was
hot.  We tested the heatshield in special wind tunnels, and shot a laser at
it.  We tested the Probe at vacuum, and at high pressures.  And a whole lot
more!  And of course we also tested all of the various parts of the Probe,
independently, at all these same conditions.  So, you can see why it took so
long to build the Probe, with all the testing we had to do.