Page 60 - Apollo Moonships

58 On bOard apOllO mOOnships
THE LUNAR SPIDER
Developed between 1962 and 1968 to operate exclusively in airless space and into the hard vacuum of the moon, the Lunar Excursion Module (LEM) was the workhorse of the Apollo Program to carry astronauts upon the surface of the Earth’s satellite using the LOR mode. In total, six LEMs landed successfully on the moon with 12 astronauts on board. The first lunar landing took place on July 20, 1969, and the last one on December 11, 1972.
LUNAR EXCURSION MODULE CHARACTERISTICS
The LEM was a two-stage self-sufficient spaceship designed to carry two astronauts from the Apollo mother ship in lunar orbit (see page 38) down to
the surface of the moon, to serve as a base of operations during their stay,
and to return them to the mother ship. The spacecraft was divided into two sections: the ascent stage at the top and the descent stage at the bottom. Among other things, the ascent stage contained the crew pressurized cabin,
all the LEM controls and panel displays, a cluster of reaction engines used to govern the spacecraft attitude, and the ascent rocket engine with its associated propellant tanks (fuel and oxidizer). On the other hand, the descent stage housed the landing gear assembly, most of the scientific and exploration equipment (including the Lunar Rovering Vehicle, or LRV, see page 78), extra oxygen tanks, water and helium deposits, four propellant tanks, and a variable throttle rocket engine used to slow the rate of descent to the lunar surface. The odd appearance of the LEM, similar to a spider, was dictated by the fact that it operated only
in the vacuum of space; therefore, providing the spacecraft with aerodynamic features was not necessary.
APOLLO 11 LUNAR MODULE
Astronaut Edwin Aldrin is shown deploying the Passive Seismic Experiments Package (PSEP) on the surface of the moon. During flight, the PSEP was stowed into one of the equipment bays of the lunar module descent stage.
LEM CONFIGURATION
1 VHF Extravehicular Activity (EVA) antenna
2 VHF antenna
3 S–band steerable antenna
4 Overhead hatch
5 Rendezvous radar antenna
6 Docking target
7 VHF antenna
8 Panel vent
9 Docking window
10 S–band in flight antenna
11 Docking light
12 Tracking light
13 Window
Descent stage
3
5
11
12
19
20
23