Gemini Gravity Simulation Experiment

Spaceflight moment. I just got hold of an amazing document. It is an original NASA training manual that Jim Lovell (he signed it) used as commander of the Gemini 12 mission. (Gemini was the human spaceflight program that preceded the Apollo moon missions.) The manual provides an overview of research into the possibility of creating artificial gravity (a gravity gradient) by linking two 1960’s era spacecraft in orbit and inducing a specific angular velocity around the center-of-gravity of the linked craft.

At the time, the notion of artificial gravity induced by rotational momentum was no exactly “rocket science.” By the time Commander Lovell and Gemini 12 got off the launchpad in 1966, Stanley Kubrick was well along in the filming of 2001: A Space Odyssey, which depicted a large, circular, Earth-orbiting space station with hotel, radiating out from and spinning around a central axis and producing sufficient gravity so that visitors to the fictional station could meander by foot.

In real life, according to this manual, Lovell would take a Gemini vehicle into orbit, dock it with an Agena Target Vehicle, connect the two vehicles with a 100-foot long Dacron tether and gently back away from the Agena vehicle. (The Agena vehicles were the platforms that future Apollo astronauts used for practice, docking and undocking just as the moon-bound Apollo Command Modules would have to dock with the Lunar Excursion Modules.) The operation would be a delicate one. The Dacron tether had a load tolerance of 1000lbs. If the Gemini and Agena were travelling at a relative rate of separation greater than 5 feet per second as Lovell backed away and the tether became taut, the Dacron cord would break. Once appropriately positioned, the Gemini’s forward and side thrusters would generate 49lbs of thrust in total, just enough to impart an angular velocity around the conjoined crafts’ center of gravity to produce 1/10 g-force in the Gemini capsule.

The authors of the manual noted that this attempt to create artificial gravity through a joined system could have important practical applications for future space travel. There is way more analysis in the manual than what I suggest here. Graphs showing potential oscillations and loads and breaking points in the system. Really detailed, smooth and precise plots that make me wonder “how did they do that before Excel or Minitab or laser printers?” The really interesting question I need to investigate now is this: did they go through with the test and was it successful?

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