Sled Driver

the cockpit passing through 52,000 feet. I finally settled on peanut butter
sandwiches; they seemed to work fine for me. We occasionally had visitors at PSD.
One morning a small group of cadets joined Walt and me for our preflight meal.
They ordered steak and eggs to keep with tradition. They looked bewildered as I hit
the peanut butter and Walt dined on frosted flakes. During the preflight meal, the
crew chief came to our small dining room to brief us on any problems with the jet.
We were also notified if our tankers were having any problems.
The tankers were KC-135Q aircraft that were able to refuel the SR-71 in flight.
They carried the JP-7 necessary for the fuel-thirsty Sled. If they weren't going to be
there with the gas, we weren't going. About an hour and a half before takeoff time
we went to the locker room to take a mini-physical and get dressed for flight. A
technician took our temperature, blood pressure and insured we could clear our
ears. If one of the crew was unable to fly, the mobile crew would fill in and fly the
mission. In all the flights I observed, I never saw this happen. Scheduled crews rarely
missed their turn in the Sled.
SUIT UP
Although the SR was configured so crews could fly without the space suit, we wore
them on every flight. This procedure created a positive check of the aircraft's double
oxygen system, and provided additional protection to the crew in case of ejection.
Physiological Support Division technicians handled everything pertaining to the
space suit. They helped the crews into their suits, ran all the checks, and then
assisted the crews as they strapped into the cockpits. PSD personnel were experts
on the effects of high altitude flight on the human body. Their personal assistance
and expertise alleviated many potential problems in the cockpit.
The loss of cabin pressurization and nitrogen evolution in the body were two
dangers that faced high altitude flyers. The space suit and cockpit protected us from
these hazards. The ambient air pressure at high altitude is so low that unpressurized
liquid evaporates in seconds. Without protection, human body fluids would boil
away. At high altitude, the cockpit was pressurized to 25,000 feet. This meant that
although the airplane might be flying at 75,000 feet, the cockpit would have the air
pressure of 25,000 feet of altitude. The space suit provided backup protection if
cabin pressurization failed at high altitude. If pressurization were lost, the space suit
filled with air to provide the required air pressure on the body.
Another process happens at the low ambient pressure: nitrogen evolves from
solid tissues into gas bubbles, usually near body joints. Sometimes the gas bubbles