RETURNING TO EARTH

AFTER the astronauts have ex-plored the moon's surface, placed scientific instruments there and collected rock samples, they embark on the most perilous part of the whole trip - take-off from the moon. The lower portion of the lunar module is separated from the upper portion in which the astronauts stand. The lower portion becomes a "blast-off" pad for the ascent portion and remains behind. The ascent portion lifts itself off by its own rocket engine and is guided by the astro- nauts into moon orbit 70 miles up for reunion with the service and command module. If the ascent rocket had failed the two men would have died on the moon. After joining the command module the astronauts transfer for the flight back to earth.

KEY TO NUMBERED PARTS (1) Lower portion of lunar module acts as a launch pad and is left behind. (2) Ascent rocket engine "blasts off" the upper portion. (3) Fuel tanks for ascent engine. (4) Rear cluster of directional control rockets. (5) Rocket fuel supply and valves. (6) Aft equipment bay. (7) Docking hatch: astronauts crawl through here when linked to command module. (8) Forward rocket cluster. (9) Observation windows - both sides. (10) Moon access hatch sealed. (11) Forward rocket cluster. (12) Astronauts at flight controls. (13) Docking windows. (14) Steerable radar antennae. (15) The lunar module joins up with command module. (16) Command module separates from service module and heads home to earth.