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?
Whether they are executing a precision rendezvous and docking maneuver with the Mir space station or greasing another shuttle landing, astronauts routinely demonstrate that they are among the best pilots on the planet. But back at the beginning of America's space program, it looked like just about anybody could have done the job--and the overqualified men tasked to fly Project Mercury knew it.
"I initially said they should take one of those circus performers they'd shoot out of a cannon because Mercury wasn't a "pilot in space,' it was a "human in space,' " says Wally Schirra, a member of NASA's first astronaut class. "We didn't really contribute very much to the flight of the vehicle. We were lab specimens."
On Mercury, the astronaut was along for the ride. A booster would launch him and retrorockets would bring him back down. In between, nothing on the Mercury capsule would allow him to perform the simplest of pilot acts: alter his flight path. Sure, he could turn, pitch, and roll this way and that. He could see where he came from and where he was going. But for the Mercury astronaut, where he was going was a done deal only minutes into the mission. The very instant the booster's engines shut down, the capsule's trajectory was set.
But things began looking up for NASA's fledgling astronaut corps in December 1961, when NASA unveiled its second spacecraft design, the Mercury Mark II. Black and white and, unlike its predecessor, a two-seater, it was soon renamed Gemini, after the zodiac sign for twins. But many of the pilots who would ride the enlarged Mercury-type capsule into orbit gave the spacecraft another handle. They called it the Gusmobile.
That's "Gus" as in Virgil I. "Gus" Grissom. "Gus really had a big hand in everything, from the way the cockpit was laid out to what instruments went where," says John Young, Grissom's partner on the first manned Gemini flight, Gemini 3. "It was his baby."
Grissom, like Schirra, was a member of NASA's "Original Seven" Mercury astronauts and on July 21, 1961, became America's second man in space. But the same suborbital Mercury flight that put Grissom in the history books did something else. It made him the odd man out.
"When Gus finished his Mercury flight, he knew he was out of the loop because we had to go through the seven," Schirra says. "And he looked at it and said, "My God, we are not going to have that many flights! I'm going to go up to St. Louis and play with Gemini.' So it was essentially his spacecraft. He practically had it to himself."
NASA had been wrestling with the idea of a Mercury followup since 1959. Its goals evolved into something more lofty and much more complex than just putting two men inside a somewhat larger Mercury capsule and hurling them into the unknown. It became a testbed in which to prove all the major concepts needed for a manned mission to the moon. Could man survive in zero-gravity long enough to travel from Earth to the moon and return? Could astronauts manipulate their trajectory with enough precision to rendezvous and dock with another spacecraft? Could an astronaut leave the relative safety of the spacecraft's cabin and "walk" in space? And finally, could an astronaut control his spacecraft's reentry into Earth's atmosphere?
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."
The Gemini astronauts had achieved history's first rendezvous in space--although their competition saw things differently. "Around that time," Schirra explains, "the Russians flew two spacecraft within three miles of each other and said they performed the world's first rendezvous. No way was that rendezvous! It was a passing glance--the equivalent of a male walking down a busy main street with plenty of traffic whizzing by and he spots a cute girl walking on the other side. He's going "Hey wait' but she's gone. That's a passing glance, not a rendezvous." He adds: "Now if that same male can cut across all that traffic and nibble on that girl's ear, now that's a rendezvous!"
Gemini's usual target was an unmanned Agena-D. Launched by its own Atlas rocket 100 minutes prior to the crew's launch via Titan, the Agena was a combination docking target and booster rocket. At one end it had a gimbal-mounted, turbopump-fed 16,000-pound-thrust rocket engine and plenty of fuel. At the other was a Gemini-compatible docking target replete with radar transponder, flashing xenon lights, shock absorbers, and mooring latches. For the world's most proficient test pilots, the Agena was a piece of cake.
"Docking in space is cool," says Dick Gordon, who was a Navy test pilot before he flew Gemini and Apollo missions. "As a young aviator I'd done my fair share of air-to-air refueling and that was what docking with the Agena was like. You get yourself lined up, maybe five to ten feet out. And if everything looks all right and you look lined up with the docking cone, all you do is add a little thrust with the translational controller. And if it looks like you're going too fast you take a little off with the translational controller. And just like flying an aerial refueling, you did all this with just the old Mark-VIII eyeball. There was no optical sight on board like I had for docking the [Apollo] command module with the lunar module. It was all feel."
The actual encounter occurred at a walking pace: half a foot per second. Gordon calls it "little more than a bump in the road and hardly felt." The Gemini's index bar--a vertical bar on the end of Gemini's nose--slid into a V-shaped notch at the top of the Agena's docking cone. At the point of contact three clamps inside the Agena grabbed hold and pulled the spacecraft closer, and electrical cables connected, enabling the astronauts to control the Agena-Gemini stack.
"I had the ability to maneuver the Agena from the right side of the Gemini's cockpit," Gordon says. "There was this little coder--the "Orphan Annie coder,' as I called it, because it looked like one of those little ring decoders kids used to get. By working the coder's rings and hitting "send' by moving a lever to either "0' or "1,' you could transmit signals to the Agena. You could do everything from tell the Agena what direction it should point, to fire its big engine."
During the Gemini 10 and 11 missions they did just that. The right-seaters on those missions (Michael Collins on Gemini 10 and Dick Gordon on Gemini 11) ended one of their long digital conversations with the Agena by sending the sequence 041-571-450-521-501, the command to fire the engine. After an 84-second pre-fire routine, John Young and Collins on Gemini 10 and, later, Pete Conrad and Gordon on Gemini 11 became spectators at an out-of-this-world fireworks display.
"At first, the sensation I got was that there was a pop, then there was a big explosion and a clang," John Young said at a mission debriefing following Gemini 10. "We were thrown forward in the seats. Fire and sparks started coming out of the back end of that rascal. The light was something fierce and the acceleration was pretty good. The shutdown on the PPS [Primary Propulsion System] was just as unbelievable. It was a quick jolt and the tailoff I never saw anything like that before, sparks and fire and smoke and lights."
On September 14, 1965, 25 seconds' worth of sparks, fire, smoke, and lights lofted Gemini 11 to a new Earth orbit and an altitude record of 853 miles. Conrad and Gordon became the first humans to witness the planet in true spherical splendor.
"We went over the top and I said, "Houston, Eureka! The world is really round,' and they rogered," Conrad says. "I didn't think much about the comment at the time--that is, until I got back to the astronaut office and got all these letters from the Flat Earth Society in which they explained to me that the earth was flat. But they did acknowledge that it was indeed disk-shaped."
"Right after we got into orbit we were supposed to "station keep' or fly formation with the booster," Borman says. "We were flying formation and taking photographs and infrared measurements and I started calling it a "bogey,' which is an old fighter pilot term. Well, a lot of the UFO freaks on the ground picked this up and said we had seen a UFO because we had referred to our booster as a bogey. Just this past year I got a call from a producer at "Unsolved Mysteries" and they said, "We read your account about your seeing a UFO on Gemini 7 and would you come on the program?' I told them: "I'd love to come on your program because I'd love to straighten that out.' I explained what it was I saw and I said, "I don't think there were UFOs,' and the producer said, "Well, I'm not sure we want you on the program.' "
Particularly for Gemini's long-duration crews, working the hind end of the maxim "what goes up must come down" was a happier affair. To prepare for reentry, the crew activated the two sets of reentry thrusters ringing the Gemini's nose, turned their spacecraft blunt-end first, and explosively jettisoned half the white adapter section, revealing four solid propellant rocket motors. At a precise instant designated by both Houston and the world's first digital computer in a manned spacecraft, a 2,500-pound retrorocket exploded to life for 5.5 seconds, followed in quick succession by three others.
Dick Gordon had been in space for three days on Gemini 11 and thought retrofire was "nothing to write home about." But after 190 hours and 15 minutes of zero-G, retrofire was a real boot in the pants for Gordon Cooper: "I think [the retrorockets] only provide about one-half G of acceleration, but when they kick in, especially after eight days, they make you feel you are going to go around the world the other way."
As the Gemini began its long, shallow, half-hour dive into the atmosphere, one last segment of adapter section was jettisoned, exposing the Gemini's heatshield. Using the reentry control system mounted in the spacecraft's nose, the command-pilot rolled the spacecraft 180 degrees, or "heads down," so that the horizon was visible in the upper portion of his cabin window. Over the next 10 minutes the crew members split their time between working the reentry checklist and grabbing final glimpses of the world from Earth orbit.
At 400,000 feet the Gemini descended into the first tendrils of upper atmosphere and an ion-induced light show began. Wally Schirra likened reentry to being at the base of a Bunson burner's flame. Frank Borman thought it was like "flying in a neon tube." John Young remembers the colors: "The first thing you notice is at about six and one-half minutes after retro fire a slight orange haze that envelops the spacecraft. And this haze layer increases and changes color to a dark green. It's a very beautiful thing. And then orange sparks of ablative material start flying forward."
"We had a window-mounted 16-mm camera and I decided that during this reentry I was going to take the camera and hold it up against the window to get a really good view of the reentry plume," he says. "And I did that and we got some very good shots. But you can also see where the Gs built up it was hard to hold. You can tell that the camera does change its position. I let go and it slammed into my chest. But we got some pretty good pictures on that one."
By 40,000 feet the Gemini crew deployed a drogue chute, which further slowed and stabilized the spacecraft. At 10,000 feet the Gemini's 58-foot-wide main chute unfurled and the spacecraft pitched forward so its occupants could return to Earth upright.
"The Gemini splashdown was easy," Dick Gordon says. "You are sitting up, and I remember going submerged and seeing the change in the color of the ocean. And then you pop back up like a cork."
Moments later, as the nose-mounted reentry control thrusters hissed and smoked, each Gemini crew discovered two very important things about the Gusmobile. One was that the heatshield, which had so recently prevented them from being incinerated, was now acting like a frying pan, making the cabin uncomfortably hot and sticky. Wally Schirra describes the other: "Gemini was my favorite spacecraft," he says, "but it made a lousy boat."
While Gemini was making crews seasick, NASA was building the next generation of spacecraft, one that would fly beyond Earth's orbit. That too was a stunning accomplishment, but the Apollo craft that would take us to the moon was more of a transport--not the hot and nimble fighter that was the Gusmobile.