Apollo Expeditions to the Moon|
DESCENT ENGINE FIREDMcDivitt and Schweickart entered the lunar module on the third day in orbit and powered it up to check out its systems and to fire the descent engine while in the docked condition. The engine burn lasted more than six minutes, during which time the crew controlled the engine manually, and also demonstrated digital-autopilot attitude control. After returning to the command module, the full crew made the fifth of the docked maneuvers, using the service propulsion system.
Early on the fourth day, Schweickart and Scott began their extravehicular activity, that spectacular and exhilarating solo performance outside the spacecraft. Unfortunately, Schweickart had been affected by a form of motion sickness during the previous days, a difficulty that later led to a regime of zero-G flights for all crews during the last days before launch. But this time it affected the planned time line for the EVA, and it was decided to reduce the activities outside the spacecraft.
Schweickart went into the lunar module, which was depressurized, and left it by way of the exit hatch that would later be used by the astronauts who landed on the Moon. He stayed around the platform - the "front porch" as the astronauts called it - by that hatch for about three-quarters of an hour, checking the handholds and the lights that had been trained on specific portions of the spacecraft. Scott, meantime, had opened the command module hatch and clambered partially outside, still hooked to the spacecraft through a life-support umbilical system.
Schweickart was using a portable life-support system in his EVA, checking it for the first time outside. Both men detailed their experiences, took some photographs, and retrieved some thermal samples, testing the maneuverability of the space suits and the accessibility of the sample locations on the spacecraft. We had planned to have Schweickart move externally from the LM to the command module, to verify a way of getting from one spacecraft to the other if the tunnel were not available. This step was not completed beyond evaluating the specific handholds that would have been necessary to such a transfer.