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8:35 PM taxiing out for takeoff.
8:45 PM Off the ground and climbing. The oscillating secondary mirror wiring problem
has been fixed and everything looks good. The OSM chassis was moved to another place in
the console to make room for the computer work station I am now t yping on. In order to
move the OSM chassis the interconnecting cabling had to be replaced with new wiring. The
new wiring had several bad splices which were occasionally opening up causing
intermittent problems. So that is what caused the problems.
9:00 PM Passing through 27,000 feet. Time to turn off the flow of liquid nitrogen to
the telescope cavity.
9:05 PM I have all my systems up and running now and I am ready to open the telescope
aperture door when we get to about 35,000 feet. This door is one of the many unique
features of this aircraft. Most planes don't fly along at Mach .74 w ith a huge door
open in the side of the plane! A great deal of time and money has been spent in getting
the air to flow smoothly over this opening which is about 6-feet square. Since the
telescope has to look through this flow of air blasting across the d oor, it's essential
that it be nice and smooth. Otherwise the image would be distorted by the turbulence.
Have you ever noticed heat waves coming off the surface of a hot road? It causes
everything to shimmer because the air is unstable. It's the same thi ng here, only the
air is moving hundreds of times faster!
9:12 PM We're up to 36,000 feet already. Almost time to open up the door...
9:15 PM Now I'm opening up the aperture door which is also called the "dome". I also
have our powerful air compressors turned on. There are three of them, and at any given
time one is a standby unit and the other two are running. Each one is driven by a 17
horse power electric motor that draws 50 amps of three-phase 220 volts. That's gobs of
power.
0728 UT OK, Let's get switched over to the type of time we actually use here which is
24-hour universal time, also known as GMT for "Greenwich Mean Time" or UT for "Universal
Time". UT time is the same all over the world with no time zone s or daylight savings. So
it is very easy to coordinate operations which span different parts of the world. If we
tried to use local time we would have to change our clocks about 5 times during a flight!
0738 UT In 11 minutes we'll turn on to our first observation leg and start looking at
Alpha Boo. The experimenters will use this to set up and adjust their equipment.
One of the neat things about flying out of Hickam Air Force Base is that we can order
these really nifty flight meals from the Air Force for $2.15. It's the greatest deal on
earth. It comes in a cardboard box that says, "Hickam Air Force Base Flight Kitch en -
Crossroads of the Pacific - Hale Aina Mokulele" Here's what I get for my $2.15:
Not bad for the money, eh? Anyone know why the potato chip bag is about to pop? The
answer should be worth some extra credit to someone...
0805 UT I've now adjusted the infrared focus of the telescope for the experimenters.
It focuses at a different place than it does for visible light. More extra credit...
Explain that!
0816 UT Headed up to 39,000 feet now. The cabin altitude is 8200 feet. It's impossible
to keep the cabin altitude at sea level because the pressure differential between the
inside and outside would be too high for the skin of the plane. I t would not be able to
take it. As it is, the plane expands and contracts each flight as the cabin is pressurized
and then depressurized. These pressure cycles are one of the things that cause metal
fatigue and wear out jet aircraft after thousands of fli ghts.
0826 UT We are now level at 39,000 feet. We'll remain at this altitude until we've
burned off some fuel and become a bit lighter. Sometimes we do short five-hour missions.
Then we don't have to carry nearly as much fuel and we can go dire ctly up to 41,000 feet.
The additional two and a half hours of fuel we carry on the longer flights makes a big
difference in performance.
0830 UT I stayed up till 4:00 AM this morning and took a one hour nap today to try to
get adjusted to nights. Let's see if I can get through this mission without falling out
of my chair...
0925 UT Things have settled down to routine now. I just adjusted the gain settings for
the chassis that controls the torquer motors that steer the telescope. The computer says
that I made it slightly worse by fooling with it. I can't real ly tell the difference,
and the investigators say it's better. There's a saying, "If it's not broken, don't fix
it." Good advice sometimes. I have to crawl under the table top and lay on my back on the
floor and watch a monitor above me while I adjust a s et of tiny little screws in a
chassis near the floor. It's hard to see in there and get the adjustment tool (we call it
a "tweaker") on the screw while the plane is bouncing around in light turbulence. I have
a little flashlight I carry in my flight suit shoulder pocket for jobs like this one.
Right now is typical of how the flights usually go. There is not too much chatter on
the interphone line. People are all relaxed and going about their business. I'll break
out a book in a little while and read, but I have trouble really concentrating on t hese
flights. Between being tired and slightly hypoxic from less oxygen than I'm used to, it's
hard to do much heavy thinking. Right now we're bouncing around as well. That doesn't
make for great reading conditions.
0938 UT We'll be climbing that last 2000 feet soon up to 41,000. When we get this high
we really just drift up the last few thousand feet. The plane is near its maximum cruise
altitude and the air is just too thin up here to allow a much higher altitude at this
weight. We sometimes go up to 45,000 feet but it's a fairly big deal. Everyone on those
flights has to have a current Air Force high altitude certification. No one can have a
beard since at least half of us will be on oxygen at all times. Hair, makeup, and any
oil-based creams are fire hazards in a pure oxygen environment. High altitude physiology
is pretty interesting stuff. If we lost pressurization at 45,000 feet, even 100 percent
oxygen at ambient pressure would not be enough t o keep us conscious. We need to breath
oxygen under pressure. The regulator forces it into your lungs and you have to blow out
to exhale. I won't go into it unless I get a question from someone. High school science
or physics classes could have fun with t his. You get into partial pressures and a bit of
physiology - how your body works.
1032 UT (12:32 AM Hawaii Time) Well, the flight is about half over now. We're cruising
along 8 miles high and about 200 miles from the Hawaiian Islands at the moment and
zigzagging in an easterly direction. We'll fly north for another 21. 7 minutes and then
head south east for 45 minutes. Then one fairly long leg back towards the Islands.
1256 UT Another hour and a half to go plus that much more once I get on the ground. So
far it's been an uneventful flight.
1344 UT Not too much time left so I'll end this and get ready to land.
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