QUESTION:
What will SOFIA be able to do that the KAO cannot do?

ANSWER from Ted Dunham on November 3, 1995:
SOFIA's mirror is 3 times bigger than the KAO's, so its area is
9 times bigger.  This means that it collects 9 times as much light as the
KAO does.  In addition because the mirror is bigger its angular resolution
is better because of diffraction, an effect related to the wave nature
of light.  The big problem in infrared astronomy is the very bright
background from thermal emission from the telescope and atmosphere.  The
better resolution of the telescope means that if you are looking at a point
source, like a star, you have to look at 9 times less background sky area
than with the KAO.  When you combine the larger collecting area and the
smaller background area, it turns out that it takes 81 times less observing
time to do the same observation with SOFIA than with the KAO!  An observatoin
that would take half a KAO flight can be done with SOFIA in 2 or 3 minutes!
Of course, a lot of observations will be made that take an hour from SOFIA.
These are totally impossible from the KAO - they would take 10-15 whole
flights!  Another way of looking at this is that you can do in one SOFIA
flight what we now do with the KAO in a whole flight year!

In the case of an extended object like a nebula, the benefit isn't as much -
you only gain a factor of 9.  However, you can see detail with 3 times the
resolution of the KAO.

The kinds of things that people will do with SOFIA that can't be done with
the KAO will be in looking at star forming regions in more detail, looking
at how stars form in other galaxies (that's right on the edge of the KAO's
capability), better understanding what is going on in the center of the 
galaxy, looking at the planets in our solar system in more detail and at
some wavelengths where they are undetectable with the KAO, and a bunch of
other things that I forgot and haven't even thought of yet.  It will be a
very interesting time when SOFIA starts flying.
Yours, Ted Dunham