QUESTION:
How much pressure and heat was the Galileo probe supposed to withstand?

ANSWER from the ProbeSquash activity:
See this Web site for more info: http://quest/galileo/features/probesquash.html

The Probe is intended to survive to at least the 10-bar pressure level
(one bar is equal to the pressure that we feel here on Earth at sea level).
At this point, the Probe would be 90 kilometers below the cloud tops.
Under nominal (expected) conditions, this will happen about 38 minutes
after entry, but possibly as late as 41 minutes after entry. It is
certainly likely that the Probe will continue to function at much
deeper levels (and, consequently, at higher pressures).

The Probe had to pass an acceptance test (13 bars) , and a qualification
test (16 bars). The actual design limit on the Probe is 20 bars, when we
expect to be 60 minutes into the Probe mission. At 75 minutes into the
mission, when the receiving of the Probe data at the Galileo Orbiter
ends (effectively ending the mission) due to Orbiter mission constraints,
the pressure will be up to 30 bar--10 bar over the Probe design limit! All
of the flight units and the entire descent module were tested to the 13 bar
limit in the descent-pressure-temperature chamber. One of the Probe's
instruments--the Neutral Mass Spectrometer--was actually pressure
tested until it failed, at 21 bars.

As for temperature, assuming that the Probe lasts long enough to
send data back to the orbiter during the entire 75 minutes allowed
for data transmission, the surrounding atmosphere will register
184 degrees Celsius (363 degrees Fahrenheit)--quite a change from
the roughly -162 degrees Celsius (-323 degrees Fahrenheit) at the
start of the Probe's mission!

Although the Probe is examining the Jupiter environment, we still
have to isolate the Probe from that very environment! Essentially,
the Probe is like a big thermos bottle. When the Probe was heated up
to test limits, it then took several *days* until the Probe cooled
down enough for the next test!

While this helps to keep the Probe working, it makes it very difficult
to figure out what the temperature will be *inside* the Probe for a
given temperature * outside* the Probe.

The probe has a unit temperature qualification value of 60 degrees
Celsius (140 degrees Fahrenheit).  While building and testing the
Probe, a test was run in 1983, where the Probe was put into a large
test chamber and the engineers tried to simulate Jupiter's atmosphere
while the Probe sampled the atmosphere in the chamber. Just like in
the mission, the Probe started quite cool and then was suddenly given
a very cold dose of helium which then started to warm up. Slowly at
first, but faster and faster as the test went on.  Although the test
didn't go the whole 75 minutes, the engineers could still use it to
guess what will happen.