Those procedures included using the lunar module as an active docking vehicle, relying on its engine to bring it close to the command module and connect the two. “We were trying to show all the things that we could do. It was fairly difficult” to use the lunar module in this way, McDivitt says, “because you have to look up instead of out the front, and therefore the reaction of the control systems was significantly different compared to what you could see.” Although the Apollo 9 crew “did it to prove that it could be done,” in case it ever became necessary, he says, all subsequent dockings on Apollo missions were done by the command module.
The lunar module, he says, “flew the way it was supposed to.” He wasn’t concerned at all that the fragile, oddly designed craft — which he had described in newspaper interviews prior to the mission as “flimsy” and “a tissue paper spacecraft” — would work as it should. “I don’t worry much,” he says.
As commander and lunar module pilot, respectively, McDivitt and Schweickart spent several days conducting extensive tests using the lunar module, beginning on the third day of the mission. Over the next three days, the craft’s engines were fired several times to simulate landing on and ascending from the Moon’s surface. This included the first crewed throttling of a spacecraft engine, as McDivitt manually reduced the engine’s thrust for nearly a full minute before shutting it off in a mock landing burn. On the mission’s fifth day, McDivitt and Schweickart successfully separated the lunar module’s two stages to simulate liftoff from the Moon, as the craft was designed to leave its landing stage behind as its launch platform.
Even the two television transmissions the crew produced, on March 5 and 6, were part of the engineering test. “It was in the flight plan that we wanted to check out the TV camera, make sure it worked when we got to the Moon,” says McDivitt. Broadcasting live television from the Moon would become instrumental in captivating the public and sharing NASA’s success. But for McDivitt, testing this was “just another thing to do” on the mission’s long checklist.