No one ever gave me a good explanation, though the orbit was fairly low and the
spacecraft attitude does make a difference. The satellite I worked on before
this one had a more interesting "end of life." As its orbit decayed they found
that they could use the solar panels as wings. They had to come up with novel
ways to use the detectors to make it worth while (it was a non-focusing x-ray
telescope), and they had to work out the aerodynamics of fragile solar panels
skimming in at 17k mph at 100 miles altitude, but since it was controlled
completely from a lab at MIT it became good fun for a group a grad students.
They managed to keep it flying for a number of months.

For me the most intense time was the launch. A midnight launch with seats about
three miles away is an incredible sight - a third of the sky lights up, the
ground shakes, and the 12 story rocket start moving up very, very slowly. 15
seconds later you hear the roar, startling because you don't realize you were
missing a major component of the experience. You start to notice the PA
system - "T + 2 minutes - coming up on Booster Engine Cut Off - 20 miles
downrange - everything is extremely nominal." Five minutes later there's
nothing left to see, and there are a few hundred engineers milling around
mumbling "What a rush!!!" The bars on Cocoa Beach stay open late that night.

I was spared the stress of watching them turn on the hardware a bit at a time
for the next week, but was back in Cambridge for the party as they opened the
lens for "First Light." The data was sent to us immediately, because our
political claim was that we could analyze the data and show it in near real
time, as opposed to about a 6 month delay that most spacecraft projects had.
The bitstream they sent was totally unintelligible! While everyone was
drinking Champagne, my partner and I had to figure out that the telemetry was
completely "bit reversed" because that's how it came raw from the tape
recorder - NASA had never bothered to tell us! From then on, it all started
seeming mundane.


"Navigator" wrote in message
...
I bet that was a rewarding time for you -if a bit nail biting. Why does
the orbit decay faster? I would have thought that a tumbling object
would have the same average drag on the high upper atmosphere or is it
something else?

Cheers


Jeff Morris wrote:

"Navigator" wrote in message
...

Jeff Morris wrote:

This is my telescope:

http://history.nasa.gov/SP-466/p60.jpg

And where is it now?


Dust on the sea ...

It worked great for about a year and a half (scheduled for a 6 month
mission)
but then it had a problem and lost 99% of its reaction gas, which is needed
to
keep it stabile. We managed to keep it going for another 6 months with 24/7
attention, but then resources got diverted to for one of the early shuttle
tests
(where they dropped the mock-up from a plane, I think) and it was lost.
Once
they start tumbling the orbit decays quicker and it burned up in a year or
so.
This was HEAO-2, also known as the Einstein Observatory. In many ways, it
was a
predecessor to Hubble - my boss, Dr. Riccardo Giacconi, became the first
director of the Space Telescope Science Institute and was awarded the Nobel
Prize in 2002.

For goofy pictures of 70's haircuts (fortunately not mine):
http://history.nasa.gov/SP-466/ch6.htm