Flying the Gusmobile
It didn't look remotely like a fighter plane. So why did astronauts who flew the Gemini spacecraft compare it to one?
- By D.C. Agle
- Air & Space magazine, September 1998
(Page 2 of 6)
Gemini would tell them.
What Grissom would tell the engineers at McDonnell's St. Louis plant, where the Gemini was being built, was how to make it a pilot's spacecraft. "Since we had to fly the beast, we want one that will do the best possible job," he wrote in Signal magazine before his Gemini flight. Grissom, who died with astronauts Edward White and Roger Chaffee in the January 27, 1967 Apollo 1 fire at Florida's Cape Kennedy, became a spokesman for the astronauts during the design of the vehicle. And he was determined to see that the limitations of Mercury were not repeated. In a Gusmobile, the astronaut was going to be an integral part of the system rather than a backup.
The McDonnell engineers took such preaching from a "flown astronaut" as gospel. "I would sit in the mockup for hours," Grissom wrote in Life magazine. "All I had to do was say "No, I don't like it' or "Yeah, it's okay.' When the other [astronauts] started looking at the Gemini mock-up it was pretty clear it was designed around me." Indeed, the spacecraft designers had tailored Gemini's cockpit so closely around the five-foot, six-inch Grissom that Gemini became a tight squeeze for everyone else. By July 1963 NASA had discovered that 14 of its 16 astronauts could not fit into the original Gusmobile design. Since the external dimensions and seat configurations were fixed, designers were forced to eke out a little more room by reducing the size of a safety kit and reshaping the inside surface of the hatch by the astronauts' heads.
But there were other reasons for the Gusmobile's confining dimensions. The Gemini design had to pack two astronauts, one heatshield, 1,000 pounds of fuel, five parachutes, and a whole bunch of oxygen, rocket motors, a life support system, a computer, guidance and control devices, and other equipment into a tight yet tidy 8,000-pound package--a requirement made necessary by the maximum payload weight of the booster that launched the Gusmobile and its occupants into space (see Pete Conrad, who was the pilot on Gemini 5, command-pilot on Gemini 11, and, later, commander of Apollo 12. "You did everything manually. You flew it. Apollo was all about your computer. You get 30 seconds or a minute on the stick landing on the moon and everything else was done through the computer. I don't know how much stick time I had on Apollo 12 but it was very little. But on Gemini everything was stick and that included all the burns for the rendezvous."
Logging some stick time on Gemini actually meant using two sticks, or "hand controllers." The attitude hand controller was in the center of the spacecraft, between the command-pilot on the left and the pilot on the right. (For the group of pilots flying the first piloted spacecraft, "co-" was not an option.) Within easy reach of both, the attitude hand controller did just that--control the spacecraft's attitude, or the direction in which it was pointing. By moving the controller backward or forward, left or right, or by twisting it, an astronaut fired any of eight 25-pound thrusters located in the bottom of Gemini's white adapter section, yawing, pitching, and rolling the Gusmobile.
The attitude hand controller was old news, however; it had been used in Mercury as well as on some Soviet space missions. The significant innovation on Gemini came with the insignificant-looking T-handle controllers, one to the commander's left, another to the pilot's right. These were translational hand controllers. Pushing one forward out of the neutral position in the center would fire two 100-pound thrusters at the rear of the adapter section. Pulling it back, up, or down would fire other thrusters in the center of the adapter, moving the entire spacecraft backward, up, or down from the pilots' reference point.
"The procedure is simple," Grissom said at a March 1965 press conference, shortly after putting the spacecraft through its paces for the first time during Gemini 3. "All we do is turn on the OAMS--the Orbital Attitude and Maneuvering System--and pull out the throttle I have on my left side, put the nose on the horizon, and start thrusting."
In doing so, Grissom flew history's first orbit changes; another important first came later that year during the flight of Gemini 6, when command-pilot Wally Schirra brought his spacecraft within inches of Frank Borman's Gemini 7. The maneuver required more than 35,000 individual thruster firings. "It was like the Blue Angels at 18,000 miles per hour," Schirra says, "only it was easier. There is no turbulence in space so there were no bumps in the road. Also, the Gemini was magnificent to fly! I was amazed at my ability to maneuver. I did a fly-around inspection of Gemini 7, literally flying rings around it, and I could move to within inches of it in perfect confidence."