Plan X; or, Planning White’s Small Step

The Gemini 4 crew in training, White on the left and McDivitt on the Right. Photo credit: NASA

In 1964, the launch schedule for the Gemini program was set and it was tight. Missions with new objectives would launch every eight to ten weeks taking NASA a step closer to the Moon each time. But hardware setbacks and some surprising feats by Soviet cosmonauts took a toll on the schedule. In the first half of 1965, NASA developed a plan that would see Gemini match and begin to overtake the Soviet Union in space. It was done largely in secret and known internally as Plan X. According to the original schedule, manned Gemini flights would begin early in 1965. The first, Gemini 3, would be a shakedown cruise demonstrating the new spacecraft’s manoeuverability in orbit. Gemini 4 would push the spacecraft’s systems for duration spending seven days in orbit. Gemini 5 would rendezvous and dock with a target. Gemini 6, would be the first flight with extravehicular activity – an EVA or a spacewalk. From there these objectives would be combine to create more complex and demanding missions.

But this plan was already falling apart midway though 1964. The fuel cells that would replace batteries on the long duration missions weren’t going to be ready for a launch in early 1965, and neither was the Agena docking target vehicle supplied by the US Air Force. With the original plan for Gemini 4 in tatters, Manned Spaceflight Centre Directory Robert Gilruth proposed that the mission be reconfigured for the first EVA.

Ed White and Jim McDivitt in their Gemini spacesuits. Photo Credit: NASA

With this possible new mission on the back burner, commander Jim McDivitt and pilot Ed White were introduced to the nation in a press conference on July 24, 1964 as the Gemini 4 crew. A hint at the possible EVA largely escaped notice; Gemini Deputy Manager Ken Kleinknecht mentioned that one of the astronauts might stick his head out of the hatch standing on the seat. As pilot, this would fall to White.

Within NASA, the idea of an EVA on Gemini 4 had been tossed around as early as January 1964. A preliminary proposal offered no reason not to proceed with an EVA on the second manned flight providing all the flight hardware was ready and certified in time. This combined with the impossibility of long-duration and docking on Gemini 4 started a push to get an EVA in the mission. The crew started lobbying for the change while the Gemini Program Office set to work on the technical aspects.

There were a lot of ‘if’s involved in such an early EVA. The whole thing hinged on whether the Gemini hatches could be certified safe to open and close in a vacuum. The EVA-capable spacesuits would have to be finished and certified in time. Some umbilical system connecting White to the spacecraft while providing oxygen and communications was absolutely necessary, and so was some way for him to control himself floating in orbit. Finally, and more importantly, the crew would have to be trained and ready by launch day.

White training for an EVA. Photo credit: NASA

The ‘if’s didn’t stand in the way for long. Kleinhnecht ordered McDonnell, the company building the Gemini spacecraft, to begin testing the hatches immediately. A check through the paperwork on the spacesuits confirmed they had been tested and passed for operation in a vacuum. Max Faget’s engineers got to work on an umbilical in cooperation with McDonnell engineers. NASA engineer Harold Johnson continued his ongoing work developing a carbon dioxide gun that could give a spacewalking astronaut the ability to steer himself.

The pieces started falling into place early in 1965. On March 12, Gilruth deemed the vacuum chamber safe for a full scale EVA test. This type of test was risky but necessary. While no one wanted to put astronauts through a dangerous simulation, but there was also no sense if trying an EVA without doing these simulations first.

Stills from a footage of Leonov performing history's first EVA. Photo Credit: NASA

NASA was pushing forward developing all the technical aspects of an EVA, when the Soviets made a shocking announcement. On March 18, cosmonaut Alexei Leonov stepped outside during the Voskhod 2 mission to become history first spacewalker. Never mind that the Gemini spacecraft was worlds away from Voskhod in sophistication, Leonov and his spacewalk were getting all the headlines. The Soviet mission increased pressure on NASA to certify the EVA hardware as soon as possible but it also put a level of secrecy over the whole affair. No one wanted it to look like the space agency was forcing an EVA on Gemini 4 as a hasty reaction to the Soviets’ feat. Only those immediately involved knew what plans were being made.

Five days after Leonov’s spacewalk on March 23, Gemini 3 launched and demonstrated the spacecraft’s stunning capabilities to change its orbital height and plane. There was no doubt the spacecraft was up for a four-day mission (the longest the batteries could handle), and the EVA hardware was almost entirely certified by then – the carbon dioxide gun was certified just before Gemini 3’s launch. By the end of March, Gemini 4 as good as had an EVA in the flight plan. Only NASA headquarters remained unconvinced it was worth the risk.

Manned Space Chief George Mueller heard about the proposed EVA on April 3. He was lukewarm about it but didn’t take steps to halt progress. His main concern was how such an important goal could be moved up two mission. Gilruth responded, simply and confidently, that the hardware was ready so why wait.

The hand-held carbon dioxide gun White used to manoeuvre in orbit. Photo Credit: NASA

Gilruth assigned the final certification tests of hardware to the Crew Systems Development people and the astronauts’ training increased. By April, the last piece of the puzzle was to work out flight operations so controllers would know what to do during an EVA. About a week after the Gemini 3 mission, Flight Director Chris Kraft let his junior Flight Director Gene Kranz in to the EVA planning. Kranz was assigned the task of writing the mission rules and assembling the necessary data packages. He had to get everything together controllers would need to make the EVA a success while telling as few people as possible what he was up to.

Kranz got to work on the EVA mission rules, a project he called Plan X. The secrecy forced him to adopt a strange double life in mission control. By day he worked with his controllers on the four-day duration mission and by night he returned and met with a small task force of engineers, astronauts, technicians, and doctors to workout the parameters and flight operations for an EVA.

The EVA plan remained a secret throughout April and the beginning of May. Even as the June 3 launch date neared and she shock of Leonov’s spacewalk ebbed, there was general concern that the media and the public would see the EVA as risky and reactionary. Besides, there were enough opinions in that vein within NASA. After he watched an EVA demonstration on May 14, NASA Associate Admnistrator Robert Seamans was convinced it was the right thing to do. He went to NASA Administrator James Webb and expressed his conviction that Gemini 4 should include an EVA. Webb was all for it,  but his deputy Hugh Dryden was firmly opposed. He saw it as a Cold War stunt to prove NASA could keep pace with the Russians.

Kranz eats at his console in the Mission Operations Control Room in Houston during the Gemini era, 1965. Photo Credit: NASA

On May 19, a little over two weeks before launch, every part of the EVA was certified flight ready. Seamans compiled the data and sent a document to Dryden as proof that it was a legitimate mission plan and not a stunt.

Meanwhile, Kranz had raised suspicions with his nighttime meetings but managed to keep Plan X a secret. The problem was that the controllers who would be supporting the mission from tracking stations around the world needed to know what was happening and they typically left the US more than two weeks before launch. He called a meeting of the remote site controllers one day and handed each man a double sealed envelope. They were given strict instructions not to open them until he gave the word. If instructions never came, they were to return the unopened envelopes when they got back to NASA. The package was simply labeled “Plan X” in one inch letters. Inside was a document outlining the procedures and all the data remote controllers would need for the EVA. The cover sheet read simply: “The mission rules and plan are to be used with the data you already have; however, these rules cover flight plan activities you have not heretofore considered i.e.; booster rendezvous and extravehicular activity.”

The Gemini 4 spacecraft if lifted and mated onto its Titan launch vehicle. 1965. Photo Credit: NASA

By the end of May, all that remained was announcing the mission to the public. Some wanted to keep it a secret, surprising the media and the nation with the EVA when White was already outside the spacecraft. Others wanted to announce it at the press conference 24 hours before launch. At this point, Seamans put a stop to the sneaking around. It was one thing to develop a new and risky mission activity in secret, but keeping it from the country deliberately was incompatible with NASA’s open and transparent directive. He ordered some mention of the EVA in the press kit.

On Friday May 21, the press kit for Gemini 4 was released. On the fifth page, the first item after the general release, was an outline for a possible EVA. It was a description from a previous mission – nothing specific to Gemini 4 – but it was enough to whet the public’s appetites. The same day, Kranz gave the word to controllers at remote tracking stations to open their envelopes. One by one, they all found out that White would be making an EVA on the flight. It was, Kranz said, a hell of a way to find out.

On May 25, Dryden returned to Seamans the document he had prepared outlining the EVA procedures. It bore his and Webb’s signatures certifying the mission. Although controllers knew it was coming, the Geminin 4’s EVA wasn’t formally sanctioned and announced to the public as fact until that day. All that was left for the men who planned the whole thing was to sit back and watch what happened on the flight.

Suggested Reading:

Gene Kranz. Failure is Not an Option. Simon and Schuster. 2000.

Chris Kraft. Flight: My Life in Mission Control. Plume. 2001.


  • David Shomper says:

    According to the NASA website, White’s gun used oxygen, not carbon dioxide as stated:

  • Stu Young says:

    Congrats, Amy, on your new website, and new home for Vintage Space!

    I think this was your best article yet! I knew that the announcement of the Gemini 4 EVA was held back to the last minute, but I didn’t know about all the machinations behind the scenes! Great pix, too!

    I go ’round and ’round trying to decide which space-related website is “best” – yours, Encyclopedia Astronautica, or Mr. Portree’s Beyond Apollo. Suffice it to say, I don’t think I could live without all three!

    Again, great job!

    -Stu Young

  • […] The EVA was developed in secret; the American people and many within NASA didn’t find out about the mission objective until two weeks before launch. Once he was out, the historic mission was broadcast live for the nation to hear. Read more about it on Discovery News. Share this: This entry was posted in Gemini, History of Space Science, Manned Spaceflight and tagged Gemini, Manned Spaceflight, NASA, Spaceflight, White. Bookmark the permalink. ← NASA’s Manned Venus Orbital Mission […]

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