Gemini

Gemini, Jeffrey Kluger. St. Martin’s Press (ISBN: 9781250323019) 2025.

Summary A history of the Gemini program, that prepared the way for the Apollo program in which Americans first landed on the moon.

Many of us remember the Mercury and Apollo space programs. The former was America’s entry into the space race, particularly when John Glenn orbited Earth three times and safely splashed down amid concerns about a loose heat shield. And many of us Boomers stayed up late, riveted to the TV as we watched Neil Armstrong set foot on the Moon. But many of us forget the program that came between, the Gemini program. Yet Mercury did not practice skills or utilize technology that would be crucial for a trip to, landing on and successful return from the moon.

Jeffrey Kluger, who has written previously about the Apollo program, including Apollo 13 (co-authored with Jim Lovell), fills this gap with an account of the development, missions, leadership and astronauts of the Gemini program. He begins with background, including John Kennedy’s goal for Americans to land on the moon by 1970. And he recaps the Mercury program, both what it accomplished and what it’s limitations were. Fundamentally, the Mercury astronauts were passengers, lacking the equipment to actually fly the capsule, even though they were all accomplished test pilots. And they were sealed into the capsule. They couldn’t go for space walks.

Gemini would be the program where pilots would learn to fly, maneuver, and dock the capsule as well as take space walks, which could only be done if there were at least two aboard. Also, Mercury relied on traditional batteries, which could not power spacecraft for more than a few days. Fuel cells would be used on Gemini, and after early flights would enable much longer missions.

But all of this posed significant engineering problems. They still had to control weight, even with the more powerful Titan booster. This meant ejection seats instead of escape rockets. Fortunately, they never had to use them because tests were never very assuring. At one point, there was a plan to use a parasail-type wing for landings. Tests led to repeated crashes. Parachutes, the reliable technology, prevailed. Then, there were problems with how the booster behaved.

There were early successes with a smooth shakedown on Gemini 3 and the first ever spacewalk on Gemini 4. Then the problems began. Gemini 5 set a record for time in space, but ran into fuel cell problems that threatened an early end. Gemini 6 planned to dock with a separately launched Agena vehicle. But the second stage of the rocket, launched before the Gemini, exploded in flight. Mission control came up with a new plan. Gemini 6 and 7 would rendezvous with each other, successfully coming within a foot of each other–close enough to read a BEAT ARMY sign on the porthole of Gemini 6.

Gemini 8 ended in a near tragedy when a stuck maneuvering thruster sent the capsule into an accelerating tumble. Neil Armstrong barely pulled the capsule out of it before both astronauts blacked out. Tom Stafford and Gene Cernan were the backup team for Gemini 9 when the primary team, flying into St. Louis fatally crashed in poor weather conditions. When they went up, Cernan was scheduled for a long spacewalk. It turned out that it was far more exhausting than expected. When it became uncertain that Cernan could make it back into the capsule, Stafford faced the decision of whether to cut him loose. Cernan made it back. Barely. Fortunately, the last three flights were relatively uneventful, even setting a new high orbit record to test radiation exposure.

Kluger also talks about the crucial role people on the ground played throughout. While James Webb led the agency in Washington, Chris Kraft, Gene Kranz, Deke Slayton and others provide crucial ground support. No one died in space during the Gemini program. After the fatal Apollo 1 fire, during a flight rehearsal, Gene Kranz instructed everyone at the Houston Manned Spacecraft Center to write two words on their blackboards and not erase them: tough and competent. And not another life was lost in the Apollo program.

Jeffrey Kluger’s narrative helped me appreciate how crucial the Gemini program was and how successful the program was. Astronauts, many to fly on Apollo missions, learned crucial skill. Engineers implemented new technology, including on-board computers and fuel cells. We discovered astronauts could survive long periods in space. Kluger also preserves for us the stories of these missions and the courageous and skilled people who made it possible, both in space and on the ground. Sixty years later, few are still alive to tell the stories. Kluger has ensured, in a well-researched history, that they will live on.