Extra Vehicular Support Package

This Extra Vehicular Support Package was a piece of spacewalking hardware developed for use during Project Gemini, which was a series of 19 launches, 2 initial uncrewed test missions, 7 target vehicles, and 10 manned missions flown during 1962-1966 to gain experience in key areas of spaceflight that would allow the U.S. to fly to the Moon during Project Apollo. The device was to be worn as a backpack and was meant to provide a spacewalking astronaut with supplies of oxygen to breathe and Freon to power a small hand-held "thruster gun," which would help him move around in space while attached to a long tether. The backpack was mounted outside the Gemini capsule in a cradle mounted to the rear adapter section, where the spacewalker would attach the backpack to his suit using seat belt-like straps. A unit just like this one did fly on Gemini 8 in 1966 but the mission - which included Neil Armstrong as commander and Dave Scott as pilot - ended early due to a spacecraft thruster problem, and Scott never had the chance to test the flight unit. The backpack never flew again.

Project Gemini 1962-1966

The Gemini Program was a necessary intermediate step between Project Mercury and the Apollo Program, and had four objectives: 1) To subject astronauts to long duration flights- a requirement for projected later trips to the moon or deeper space; 2) to develop effective methods of rendezvous and docking with other orbiting vehicles, and to maneuver the docked vehicles in space; 3) to perfect methods of reentry and landing the spacecraft at a pre-selected land-landing point; 4) to gain additional information concerning the effects of weightlessness on crew members and to record the physiological reactions of crew members during long duration flights.

Working on Gemini Personal Space History

by Louis Ramon

The Discovery Center recently put on display a Maneuvering Unit Backpack that was used to train the Gemini VIII astronauts. It was part of an experiment in which Dave Scott was to demonstrate the capabilities of an improved version of the Hand Held Maneuvering Unit (HHMU) that Ed White demonstrated on the first U.S. Extravehicular Activity (EVA) or space walk on Gemini IV. 

At that time, I was fortunate enough to be working for NASA at the Manned Spacecraft Center in Houston (now the Johnson Space Center) in a small newly formed group which  was given the responsibility to develop the techniques and procedures and to train the astronauts in this new thing called EVA.

When Ed White flew the HHMU, he only a few seconds of oxygen propellent in the two bottles that were part of the assembly in his right hand in the picture (above).  This job that Dave Scott was to perform on the mission was translate along handrails on the Gemini Spacecraft to the aft end where he would strap on a backpack which several times the amount of propellant (this time Freon gas) that Ed White had, pick up the HHMU, connect it to the back pack and fly over the top of the Spacecraft to the Agena (another spacecraft) to which the Gemini would have already been docked to.

As it turned out, Dave never got to do his EVA. Not long after the Gemini Capsule reached orbit, Neil Armstrong (yes, that Neil Armstrong) completed the first docking of two spacecraft in history when he maneuvered the Gemini Capsule to connect to an Agena Spacecraft which had been launched several hours before Gemini VIII. Immediately after docking, the connected spacecraft started rolling violently, Neil was forced to undock at which time he discovered the problem was that one of the thrusters on the Gemini Capsule was stuck on. His only recovery option was to activate the Capsule’s re-entry jets to slow down the spinning and then abort the rest of the mission and return to earth.

Although this was a set back for the Gemini Program and for the development of EVA Maneuvering Units, NASA had already scheduled additional HHMU testing on two subsequent flights as well as testing of an advanced maneuvering backpack, called the Astronaut Maneuvering unit) which had thrusters attached to it instead of using a hand held unit. We wanted to see which system would be suitable for use on future space systems. (Many of the people at NASA were actually were hoping that the HHMU would prove to be adequate for future use because it was much simpler than the Astronaut Maneuvering Unit.)  Because of problems the astronauts encountered with their ability to adequately hold themselves to the spacecraft during the EVAs, which in turn caused them to overheat themselves almost to the point of exhaustion, we only had the opportunity to test a maneuvering unit on Gemini X and that was one of the HHMUs. We never got to test the backpack type maneuvering unit. That would have to wait until after the Apollo moon landings when we would perform a series of maneuvering unit experiments in the Skylab Space Station during the early 1970’s.

It was during the development of Skylab Maneuvering Unit Experiment that I discovered Colorado. The Skylab hardware was designed and built by Lockheed-Martin (then Martin Marietta) in Denver and I, as Skylab Experiment Procedures Officer and a co-principal investigator for the maneuvering unit experiment, spent a lot of time working with the fantastic engineers and technicians in Denver on the design of the maneuvering unit, the development of its flying procedures, the experiment protocol and training the Skylab astronauts.  From the results of what we learned  about how to design and provide adequate restraints for EVA work and how to train using neutral buoyancy water tanks from Gemini and the Skylab maneuvering unit experiments (we even learned that we had trained Ed White, Dave Scott and the others the wrong way to fly the HHMU) , we were able to develop the successful Manned Maneuvering Unit for the Space Shuttle and achieve the dream that existed since the days of Buck Rogers, Flash Gordon and other heroes of science fiction and the Saturday matinee serials (and even today’s new movie, “Gravity”) of being able to fly through space untethered and free.



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