Project Gemini

FAS Astronomers Blog, Volume 33, Number 9.

The second phase of America’s road to the Moon began sixty years ago in 1965 with the two-man Gemini program. Gemini was a larger spacecraft than the one used for Project Mercury, and it was launched using a Titan II ballistic missile. 

Gemini was designed to teach us how to get to the Moon. 

• Astronauts would leave their spacecraft and walk in space.
• Two or more spacecraft would rendezvous with each other in orbit and dock together.
• Spaceflights would last long enough to simulate going to the Moon and back.

After two unpiloted Gemini missions, the first manned Gemini flight came along on March 23, 1965, with Gemini III. Mercury astronauts Gus Grissom and “rookie” John Young became the first pair of U.S. astronauts to go into space together. Their flight was a short three orbit mission designed to test out the Gemini capsule. 

The focus was on the maneuverability of the capsule – a skill required for future rendezvous and docking missions. Grissom was successful in changing the orbit of the spacecraft three times during the mission. Gemini III landed successfully, and the Gemini program was underway. 

Gemini III might be best known for a corn beef sandwich that was smuggled aboard. As the story goes, Wally Schirra got the sandwich from a local deli and slipped it to John Young who hid it in his spacesuit. During the flight when the astronauts were ready to eat, Young pulled the sandwich out and handed it to Grissom who took a bite before realizing that the crumbs might cause problems with the equipment, so he put it away. 

Gemini III was nicked named “Molly Brown” after the Broadway production “The Unsinkable Molly Brown.” Grissom chose it because his last spacecraft, Liberty Bell 7, sank to the bottom of the ocean. NASA wasn’t too fond of the name but went along with it after Grissom told them that his second choice was The Titanic. After this, NASA decided there would be no nicknames for future Gemini missions. 

Gemini IV would be a longer flight and included the first American “spacewalk”. The crew was Jim McDivitt and Ed White. Early in the mission, White stepped out and floated (or zipped) around for around 20 minutes. He used a “zip” gun to control his movements. There are some reports that White was having so much fun, it took some encouragement to get him to come back inside. Although, others say that White, a graduate of West Point, would never defy an order and came in when told. With the EVA completed, Gemini IV sailed on and landed four days later. 

Gemini V was next with Gordon Cooper and Pete Conrad. After 8 days in space, a new American space endurance record was set. This was also the first spacecraft to use fuel cells for electricity. Cooper and Conrad were the first crew to design a mission patch. The original patch had the words “8 days or bust”. NASA administrator James Webb was concerned. He was afraid if the mission went less than 8 days, it would be called “a bust”. He had the “8 days or bust” covered over on the patches worn by the astronauts during the flight. In the end, Gemini V was successful and showed that humans could live in space long enough to get to the Moon and back. 

One of the major goals of Gemini was a rendezvous between two spacecraft. Gemini VI was to be this mission with astronauts Wally Schirra and Tom Stafford. However, the rendezvous target, which was an Agena spacecraft, failed to reach orbit. It was then decided to fly both Gemini VI and VII at the same time and have the spacecraft rendezvous with each other. 

Gemini VII launched on December 4, 1965, with Frank Borman and Jim Lovell. They eventually completed 14 days in orbit, becoming the longest duration U.S. spaceflight – a record they held for many years. It wasn’t the most pleasant experience for Borman and Lovell. Imagine riding in the front seat of your car for 14 days with nowhere to go, just round and round the Earth. Reports were that they were quite happy to come home at the end of the flight. 

Gemini VI and its Titan II booster were assembled on the same launch pad as Gemini VII and on December 12, 1965, everything was ready. The Titan II ignited; the clock started … then the booster shut down. The clock was not supposed to start until the booster lifted off from the pad.  So, it appeared that the Titan II, with Gemini VI, would fall back to the launch pad and probably explode in a big ball of fire. 

The procedure, at this point, was for Wally Schirra to pull a D-ring to propel the astronauts to safety. However, Schirra hadn’t felt any movement. He figured the clock was in error and they were still sitting on the pad. So, he did nothing. As the astronauts sat there, on top of a huge stack of explosive fuel, the thrust subsided – and nothing happened. The spacecraft survived, the rocket survived, and the astronauts survived. It was later discovered that a dust cover was left in the engine.

Gemini VI lifted off on December 15, 1965. After six hours, Gemini VI was flying alongside of Gemini VII, and the first space rendezvous had taken place. The two spacecraft flew in formation for a few orbits and then, after 16 orbits, Gemini VI returned to Earth. 

The remaining Gemini flights were shorter. And, up until this point in the program, NASA had not docked two spacecraft in orbit. Gemini VIII, with Neil Armstrong and David Scott, would be the next attempt using a target Agena spacecraft. Both the Agena and Gemini launched without problems. Gemini VIII caught up to the Agena, flew around it for ½ hour and then successfully achieved the first docking of two spacecraft.

The joined spacecraft then flew out of communication range of mission control. Soon, David Scott told Neil Armstrong, “Neil, we’re in a bank,” The spacecraft were in a roll.

• Armstrong used the “orbital attitude and maneuvering system” (OAMS) to stop the roll, but it began again. 
• Believing the problem was with the Agena, they cycled the Agena switches on and off. That didn’t help. 
• Armstrong undocked with the Agena and backed away. The rolling got worse. 
• At this point they were tumbling end over end at around once per second. Their vision was getting blurry. They were in trouble. 
• Armstrong then turned off the maneuvering OAMS thrusters and used the re-entry control system to regain control of the spacecraft. 

Because the engaged the re-entry system, mission rules said they had to come home. Gemini VIII reentered on the next orbit and returned to Earth.

It was close. This was the first time the U.S. was in danger of losing a crew in space. And one of them was Neil Armstrong – he shows up again a bit later during the Apollo program. It turned out that one of the OAMS thrusters was firing erratically causing the spacecraft to spin.

Rendezvous and docking were still a problem. Next up was Gemini IX with Elliot See and Charles Bassett. Thomas Stafford and Gene Cernan were the backup crew. On February 28, 1966, both crews flew to St. Louis to inspect their Gemini IX capsule. The weather was clear when they took off but deteriorated as they approach the runway near the McDonald Douglas plant. Both planes came through the clouds much too low and too fast to land. Stafford turned up and around for another approach. See, for some reason, turned sharply and tried to land. His plane hit the roof of the plant and tumbled into the parking lot killing both astronauts. For the first time, NASA was forced to replace a primary crew with the backup crew.

On May 17, 1966, everyone was ready to go. The Agena was not, and it failed to make it into orbit, so the Gemini IX launch was postponed.

Another Agena wasn’t available, so the folks at NASA dusted off something called the “Augmented Target Docking Adapter (ATDA), which had been considered for an earlier flight. It launched on June 1, 1966. Gemini IX followed on June 3, 1966. However, Stafford and Cernan discovered that the protective shroud failed to detach from the ATDA, so docking was out of the question. Stafford was able to catch up to the target (now called the angry alligator) and rendezvous, but not dock, with it. 

After seven manned Gemini missions, rendezvous was successful, but docking was still a problem. This changed with the last three missions. Gemini X, with John Young and Michael Collins, and Gemini XI, with Pete Conrad and Dick Gordon, successfully docked with an Agena and used its engine to push the combined crafts to much higher altitudes. By the time Gemini XII lifted off, this aspect of the mission was almost routine.

However, for Gemini IX, X and XI, spacewalks turned out to be more problematic. The astronauts found that, despite the fun Ed White had on Gemini IV, moving and working in space was not easy. They would try to grab the side of the spacecraft and slip off. Their visors would fog up. They would come back to the spacecraft exhausted. 

Then Jim Lovell and Buzz Aldrin went up in Gemini XII. Aldrin had trained in a swimming pool – an environment that more closely matched the actual conditions in space. He brought with him, hand holds, foot holds and straps. He rested between tasks. For him, spacewalking was a piece of cake – and he taught everyone else how to do it!

The Gemini program ended with the flight of Gemini XII in November 1966. It was now on to the Apollo program to take us through the final steps to the Moon.