Gemini 9A - Objectives

Objectives

One of the mission objectives was to dock with an Agena Target Vehicle in the same manner as the Gemini 8 mission. However, during the launch of the Gemini 9 Agena on May 17, 1966, its Atlas booster malfunctioned (rather than the Agena itself, as had previously caused Gemini 6 to be recast as Gemini 6A), and it failed to make it to orbit. As a result, the Gemini 9 launch scheduled for later that morning was scrubbed.

On June 1, 1966 a substitute for the Agena was launched in the form of the ATDA (Augmented Target Docking Adapter), designed and built by McDonnell (the manufacturers of the Gemini spacecraft). The ATDA was made from the forward docking section of an Agena with the reentry control section of a Gemini. It was built using already tested equipment and launched using the Atlas-SLV3 rocket. The docking was canceled, though, after Stafford and Cernan rendezvoused with the target to find its protective shroud still attached over the docking port, which made it look, in Stafford's words, like an "angry alligator."

As well as the docking there was also a planned EVA by Cernan. The plan was for him to move to the rear of the spacecraft and strap himself into the Air Force's Astronaut Maneuvering Unit (AMU). This was the first 'rocket pack' and a predecessor of the Manned Maneuvering Unit used by Shuttle astronauts in the 1980s. It had its own propulsion, stabilization system, oxygen and telemetry for the biomedical data and systems. It used hydrogen peroxide for propellant, and because it produced extremely hot gases, Cernan's spacesuit was modified with "pants" made of woven steel known as "Chromel-R," which was later used on the gloves and Moon walking boots on Apollo spacesuits. This material was developed by the Air Force Systems Command for use in high-temperature deceleration devices for aerospace systems. (The current MMU uses nitrogen gas, which remains cold when vented.)

However, Cernan's spacewalk was troubled from the start. After pumping up his pressure suit to three and one half pounds of pressure per square inch, "the suit took on a life of its own and became so stiff that it didn't want to bend at all." He struggled to move inside his stiff suit." As soon as he left the spacecraft, he began tumbling uncontrollably. He eventually made it back to the hatch area and began the slow climb to the rear of the spacecraft where his AMU was stored. While he was disconnecting himself from his capsule and hooking up to the backpack, his heart rate rose to about 155 beats per minute. His spacesuit had "all the flexibility of a rusty suit of armor".", which made everything take much longer than expected. While making the connections, Cernan became very tired. As he sweated, his visor began to fog. He rubbed his nose against the visor the clear a hole so he could see." After making all the necessary connections, Cernan rested for a few minutes while Mission Control decided whether or not to proceed with the planned test of the AMU. Cernan, while physically exhausted wanted to proceed, but Stafford called an end to the proceedings and ordered Cernan back inside before getting a chance to fly the AMU". The device was not finally tested in space until a modified version called the Manned Maneuvering Unit (MMU) was flown by astronaut Bruce McCandless on Shuttle Mission STS-41-B in 1984, 18 years later. As a result of Cernan's experience, the AMU never again flew on Gemini, as it was not essential to developing technology for the Apollo Moon landing mission.

The Gemini spacesuit was cooled by air. When an astronaut had an increased work load he began to sweat and in the confined space of a suit the cooling system would become overwhelmed and the visor would fog. The astronaut would then be effectively blind because he had no way of wiping off the faceplate. In future Gemini EVAs, the work loads of the astronauts were reduced, but it was clear that during lunar exploration workloads could be significant and changes were made to ensure that the Apollo EVA suit would be water cooled. This was accomplished by having the astronaut wear a garment that contained many thin tubes that circulated water near the skin. It was very effective and there were very few cases where astronauts used the "High" Cooling selection even though they were working hard and on the Moon in a 100 °C sun.