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A Setback
I got
the page from Bob Binns at about 3:30 PM. Something was wrong and
all of the TIGER high voltages had dropped to zero. I ran past of
my dorm and past Derelict Junction to arrive upstairs in Crary a
couple of minutes later. Moments later, I found what we
had worst expected (up to that point), the onboard CPU had mysteriously
rebooted in flight and the instrument had come back to life in its
default mode which, incidentally, includes no high-voltage supplied to
the phototubes. Our next TDRSS command window was only minutes
away and unfortunately, I had no procedure ready to make the smooth
transition from TIGER default settings to flight settings in the
fifteen minutes that our TDRSS command window would afford us.
Commanding the instrument over TDRSS is a whole
different story from the ways in which we controlled it before.
Instead of logging into our Ground Support Equipment out at Williams
Field, we have to log in to our GSE in Palestine, Texas to send
commands to the instrument. The connection is slow; commands are
sent slowly and the replies can take up to a minute to return. In
a fifteen minute command window, this can be wholly frustrating.
I was able to send the approximately 20 commands
necessary to get all of the high voltages up in the first command
window. And luckily all of them took. In a short time,
however, I remembered that the default coincidence setting, LED
settings, and ANITA data collection settings had changed since we had
launched, and the instrument still wasn't up to its nominal flight
levels without these changes. The next TDRSS window was about 40
minutes away. By the time this command window was over, TIGER was
alive again.
I immediately set forth to create an easy-to-follow
command sheet that would make it less stressful for anyone in our group
to bring the instrument back to life in one TDRSS window, in the event
that something like this were to happen again. Which was a good
thing.
At 11:25 PM,
what we worst expected (up until now) occurred: the CPU rebooted
again. This time I was ready with the command sheet. I was
able to get the instrument up and running in one command window with a
few minutes to spare! But the story wasn't over.
Now, something worse was wrong, the reply window was
telling us that the CPU was having trouble writing to the hard
drive. With the remaining minutes in the TDRSS window, I
attempted to increment the hard drive to its next partition, hoping
that it was only something on the C: drive that was corrupt.
Reply: "Problem incrementing partition." The TDRSS window
ended and TIGER was left sending any and all of its data on ultra-heavy
cosmic rays out into space only in hopes that one of the roving TDRSS
satellites would intercept them. And luckily, it was the case, as
our TDRSS real event window showed. The night had just begun for
Bob Binns and myself.
We quickly contacted / woke up our St. Louis-based
crew, Marty Israel, Brian Rauch and Marty Olevitch to notify them of
the problem. Although we are able to get more than 95% of our
required data over TDRSS, it is still a less-than-favorable situation
in which to fly. Nothing can beat the true,
unadulterated-by-travel-through-the-airwaves data that our hard disk
would provide. Marty Olevitch, our programmer, was the most
important person to notify, and unfortunately, he was observing the
Sabbath and would be unavailable to do any hands-on work for several
hours. Brian came to the rescue, arriving at Marty's house really
early in the morning to wake him and seek advice. Marty had
ideas, including turning off the data-recording system, incrementing
the hard drive, and turning it back on again. No luck. By
4:00 in the morning, weary and exhausted, Bob and I came to terms with
the fact that our hard drive was but a pressure-chamber-encased hunk of
useless electronics. In order to lessen the strain on the CPU,
Marty recommended that we discontinue attempting to save data to the
hard drive at all. We entered command 188, 'stop storage,' one of
those commands that should never ever be entered since it is tantamount
to 'jettison hard drive' and headed off to bed thinking "TDRSS don't
fail us now!"
And if what
is
written above is as incomprehensible as a random excerpt from a bad
science-fiction novel, then my job is done.
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