Entering The Lunar Module

Taking a lunar module to the Moon was not like jumping into a boat, casting off and sailing away. This was an extremely complex, diverse and exotic machine, perhaps even more so than the CSM, and one whose many capabilities were pushed to the limit in order to save weight. The machine had already been given a preliminary check on the coast out from Earth, but now, every system was going to be tested as far as possible while they were still attached to a good CSM.

First of all, the three crewmembers had to put on their suits, although at this point there was no need to wear helmets and gloves, making it much easier to operate equipment and talk to each other. Next, they checked to ensure that it was safe to open the two hatches that separated the spacecraft - following the earlier inspection the hatches had been closed so as to ensure that a failure of the thin-skinned LM, perhaps through meteoroid impact, would not have a catastrophic effect on the command module's atmosphere. Having checked a pressure gauge, the forward hatch leading to the tunnel was removed, followed by the probe and drogue assemblies that had brought the two craft together. Having gained access to the tunnel, the LMP removed the LM's upper hatch and passed into the lander's cabin.

When the LM's battery supplies had been brought on line, the umbilical that was feeding power from the CSM could be disconnected.

Numerous items, from pens and books to the helmets and gloves that they would wear on the Moon, were transferred across for use in the time the LM would be operating independently. Valves were opened to enable the ascent stage to access water and oxygen supplies in tanks contained in the descent stage - in accordance with discarding dead weight prior to major manoeuvres, they would be left behind on the lunar surface. Communications, cooling, caution and warning, guidance and navigation, environmental control - all the systems that make a spacecraft fit to carry a human - were turned on, tested and checked. Rows of circuit breakers were opened or closed as required, based on diagrams in the checklist that gave the LMP a quick method of checking their state by simply scanning his eyes across and comparing the patterns of white or black dots.

Since being packed away within the shroud at the top of the Saturn V, the lunar module's landing gear had been tucked beneath its descent stage. Explosive devices were fired to deploy the gear, giving the LM its familiar form with out-splayed legs. At the same time, long probes that had been folded up against three of the legs were released. These probes, which extended 1.7 metres below the landing pads, would reach the surface shortly before touchdown proper. Their purpose was to provide a cue for the commander to shut down the engine while the LM was still a short distance above the ground. From there, it could gently drop under the Moon's weak gravitational attraction. The lip of the engine nozzle was only about 30 centimetres above the plane of the landing pads, and planners feared that if a small bump in the surface were to even partially plug the nozzle opening, it could result in a dangerous backpressure within the engine.

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