Lunar Orbit Rendezvous

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Transcript

Have you ever been told to follow the chain of command or else? In most organizations with a hierarchy or with a bureaucracy, there is a set way in which things have to be done. If you have a suggestion or a complaint, you have to go to your immediate superior, and not jump over anyone’s head.

If it wasn’t for one man jumping over the heads of his superiors and jeopardizing his job, we might never have landed on the moon. 

Learn more about Lunar Orbit Rendezvous and how skipping the chain of command helped make the moon landing happen on this episode of Everything Everywhere Daily.

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When John F. Kennedy announced the goal of sending someone to the moon, the idea had already been kicked around for several years. Everything up until Kennedy’s speech had been totally theoretical, however. 

As the moon program was early in its planning stages, the first thing they needed to figure out was the general strategy for how they were going to pull it off. 

There were two competing strategies for how to get to the moon. 

The first was called the direct assent.  The idea behind this was very simple. You launch a really big spacecraft from Earth, the whole thing lands on the moon, then the whole thing takes off from the moon and comes back to Earth orbit.

The benefit to this approach is that it is very simple, and at the time this was being planned, things like orbital rendezvous still hadn’t been tried. The downside to this approach is that it requires a very big spacecraft and a whole lot of fuel to power the ship. In fact, a rocket called Nova was proposed for such a mission that was larger than the Saturn V rocket which was eventually used….and the Saturn V rocket was the largest rocket ever made. 

The second strategy was called Earth Orbit Rendezvous. The primary difference between this and Direct Ascent was that you would do several smaller launches, assemble the spacecraft in Earth Orbit, then basically send the assembled spacecraft to the moon, land it, and bring it back to Earth orbit. 

This didn’t require as large of a rocket as Direct Assent did, but it still would require bringing a large craft to land on the moon and all the fuel which is required. 

This problem of getting to the moon was considered as far back as 1919 by a Russian engineer named Yuri Kondratyuk. He realized the biggest problem was that of weight. The more weight you carried with you, the more fuel you needed, which in turn was more weight, etc. 

He came up with the idea of a segmented spacecraft that only used the parts necessary for each step of the trip, thereby minimizing weight, and thus fuel. This weight saving strategy was called Lunar Orbit Rendezvous.

The leadership at NASA during the time they were considering their moon strategy, did not have this option on the table. 

In 1958, the Space Task Group also came up with the idea of Lunar Orbit Rendezvous, but the idea didn’t catch on.

It was an engineer by the name of Tom Dolan who really believed in the idea. He developed a full report indicating how it could be done. He too got nowhere with the idea as no one in NASA believed that it could be done.

Finally, the idea was championed by an engineer named John Houbolt. 

The main area of resistance in the early 60s was the idea of orbital rendezvous. It hadn’t been done, and no one was even sure if it could be done. Even at a theoretical level, it was a very difficult and complicated maneuver. Many NASA officials thought it was so difficult and dangerous, that any proposal which relied on it, especially a rendezvous in moon orbit, was out of the question. 

Houbolt was determined to get this idea into the right hands because he knew the success of the moon landing program depended on it. This is where he decided to bypass the NASA hierarchy and go over the heads of his superiors. He wrote a lengthy letter to NASA Deputy Administrator Robert Seamans, which started with the line, “Somewhat as a voice in the wilderness, I would like to pass on a few thoughts.”

In the letter, he said, “Do we want to go to the Moon or not?” “Why is Nova, with its ponderous size simply just accepted, and why is a much less grandiose scheme involving rendezvous ostracized or put on the defensive? I fully realize that contacting you in this manner is somewhat unorthodox, but the issues at stake are crucial enough to us all that an unusual course is warranted.”

It took two weeks for Seamans to reply, and said: “it would be extremely harmful to our organization and to the country if our qualified staff were unduly limited by restrictive guidelines.”  He promised Houbolt that more attention would be given to Lunar Orbit Rendezvous. 

At first, the idea still encountered resistance, and some senior engineers would even disparage him and his work to other senior NASA officials. However, over time, the science behind the idea won out. 

The requirements for Direct Assent or Earth Orbit Rendezvous was just too difficult, and Lunar Orbit Rendezvous was the only thing that could realistically fit on a single Saturn V rocket. One by one, NASA engineers and management began accepting the need for Lunar Orbit Rendezvous and on July 11, 1962, NASA had a press conference where they announced the strategy. 

It worked. The Lunar Orbit Rendezvous strategy is what every Apollo mission used to go to the moon.

The Lunar Module which was eventually used was approximately 5x smaller than the proposed direct assent craft. Moreover, half of the lunar module was left on the moon, further reducing the weight and fuel.

It is a credit to NASA that they were willing to listen to all ideas and adopt what was best, not just what was politically expedient.

John Houbolt wasn’t fired or demoted. In fact, he was given a medal for exceptional scientific achievement by NASA for his contributions. He later penned a similar letter in 1981 to NASA director Kris Kraft about the dangers of the Space Shuttle’s heat tiles and how damaged tiles near the strut which connected the large fuel tank could have devastating consequences. It was damaged heat tiles which caused the loss of the Space Shuttle Columbia in 2003. 

These ideas of Lunar Orbit Rendezvous, Earth Orbit Rendezvous, and Direct Assent are not things that are relegated to history. NASA’s new Artemis moon program, and work being done by Space X, have brought these ideas back to the forefront.

This time, however, technology and mission requirements have changed, and the current approach is towards a direct ascent strategy. Now the goal isn’t just to save weight and fuel, but to create a spacecraft which can be reused multiple times.