QUESTION:
Could you describe the largest technological difficulty you have had so far on
this mission.

ANSWER from Mike Haas on Oct.15,1995:
I am not sure whether your question is specifically about technolgical
difficulties on the "Live from the stratosphere" flight of October 13 or
whether it is a more general question about the Kuiper Airborne Observatory
(KAO) program, so I will answer it both ways!

The flight of October 13 was technically and scientifically a very good flight
and there were few, if any, serious problems. There was a small problem with
the pointing of the telescope early in the flight, but it was quickly resolved
and we would be extremely happy if all KAO flights went so smoothly. The
largest technological challenge in preparing for this specific flight was
certainly the installation of the antenna and communications equipment that
permitted live broadcasts from the aircraft. This is a relatively new
technology and was a major effort for the facility - many people worked hard
for many monthsto allow the aircraft to be on the internet while airborne.

However, I think the more interesting question is what are some of the major
technical challenges that the KAO has faced over the years?
Here again, I am not sure you are asking about technical difficulties or
technology development - plenty of both have occurred. Since the KAO has flown
about 80 missions a year for 21 years and supports about 20 to 30 different
teams of scientists each year, there have been many, many technical
difficulties: burnt out engines, broken detectors, ect. One time we hit a flock
of ducks during landing and broke the front windshield and damaged the nose of
the plane. 

For me, however, the greatest technical difficulty occurred in November, 1983
when my recently completed instrument developed a vacuum leak. The instrument
was a cryogenic spectrometer (The word 'cryogenic' means it uses liquid
nitrogen and liquid helium for cooling; a 'spectrometer' is an instrument that
splits light into many colors and measures the amount of each color in the
spectrum separately). The spectrometer weighs about 205 lbs including a large
vacuum can that looks alot like a 55 gallon oil drum, but in fact, is a large
thermos bottle which keeps the optics and detectors at a temperature of -456
degrees F during a flight. One day my vacuum system developed a leak - it was a
very small, but very significant leak, because it prevented me from getting my
instrument cold enough for the detectors to work properly. Ironically, the
vacuum leak only occurred when the system was below -300 degrees F.

When the spectrometer is this cold, the leak was very hard to find, but
whenever I warmed it up, the leak always mysteriously disappeared. It me four
months of laboratory work to develop a reliable technique for finding the exact
location of the leak, and then it took me several more months to disassemble
the instrument, replace the defective part, and then reassemble and test the
spectrometer in preparation for its next flight.

As far as the greatest technological development, that has to be the
improvement in the capability of infrared detectors over the life of the KAO
program. When the KAO started flying in 1974, scientists used instruments with
one detector to measure infrared radiation emanating from a single point on the
sky. Now, 21 years later, we have arrays that contain more than 10,000 separate 
detectors, allowing us to actually take infrared images of the objects we
study. Moreover, these new detectors are about 10,000 times more sensitive than
the single detectors used on the first KAO flights. This is a tremendous
technological leap and it has allowed us to do work that cuold not even be
contemplated when the KAO was first commissioned over two decades ago.

As you can see, this was a great question! I hope you don't mind if I gave
several different answers!