July 20, 1969 was a historic day for America and the world. While the world watched on TV, astronaut Neil Armstrong took mankind’s first steps on the moon.
At its Bethpage, N.Y. facility, Grumman Corporation, now part of the Northrop Grumman Aerospace Systems sector, designed, assembled, integrated and tested the Lunar Module (better known as the LM), the famed Eagle of the Apollo program. Between 1969 and 1972, six Grumman lunar modules carried 12 astronauts to and from the surface of the moon and one – Aquarius – served as a lifeboat for three astronauts during the ill-fated Apollo 13 mission.
Of course, there were a great many other companies that were an integral part of the LM’s success, but for this article, we concentrate on the Long Island, NY company that was so instrumental in aviation and the Apollo program. TRW also provided critical software for mission analysis and simulation, guidance and trajectory control, an abort guidance control, and a backup communications system.
As NASA’s official history of the Apollo hardware puts it, the LEMDE (Lunar Module Descent Engine) “probably was the biggest challenge and the most outstanding technical development” of the entire program.
Two other companies that are now part of the Electronic Systems sector also made significant contributions to the mission. Dalmo-Victor designed and supplied the S-band 2-Gigahertz high-gain antennas that made possible the transmission of the live images from the moon's surface. Amecom Division of Litton Systems, Inc. produced flush-mounted antennas that transmitted and received all S-band signals during near-Earth operation and served as backup for the high-gain antenna in deep space. Four antennas were mounted on the command module.
Legacy Northrop provided the earth landing system that included the space vehicle recovery parachutes for Apollo 11.
Key systems on the LM were:
Electrical power system (EPS)
: The EPS contained fuel cells and batteries and provided both direct and alternating current electricity. Most of the EPS's systems were in the Service Module (SM), but the Command Module (CM) carried three batteries.Guidance, navigation and control system (GNCS)
: This system measured and controlled the spacecraft's position, attitude and velocity. It included inertial, optical and computer subsystems. The inertial subsystem used accelerometers to measure the spacecraft's speed and rotation along its three axes. The optical system included a telescope, a sextant and an electronic system that sent optical data to the spacecraft's computer for navigation purposes. The computer system analyzed data from the other subsystems as well as from manual commands from astronauts.
The computer would send the commands to the spacecraft's propulsion system to make course adjustments. The computer also had a digital autopilot that could control the spacecraft during all phases of the mission.Stabilization and control system (SCS)
: This system included controls and displays for the crew of the Apollo to adjust the spacecraft's rotation or velocity manually. The system sent commands to the spacecraft's propulsion system.
Service propulsion system: Located in the SM, this propulsion system included four tanks of hydrazine fuel and nitrogen tetroxide oxidizer. These substances are hypergolic, which means they ignite spontaneously when mixed together. The system used helium tanks to pressurize the fuel lines. The system's rocket engine produced up to 20,500 pounds (91,225 Newtons) of thrust. NASA mounted the engine on a gimbal, which is a support that can pivot. By pivoting the engine in the right direction, the spacecraft could maneuver to the right attitude and trajectory.Reaction control systems (RCS)
: The RCS was a system of engines and fuel tanks. It was partly used as a redundant system, meaning it could control the spacecraft's movement if the main propulsion system went offline. Both the CM and SM had an independent RCS. The SM had four quads, which were groups of four rocket engines. Each engine could supply 100 pounds (445 newtons) of thrust. The CM had two six-engine groups, with each engine capable of supplying 93 pounds (413.9 newtons) of thrust. The CM's RCS also provided spacecraft control during re-entry.Telecommunication system
: This system provided intercommunication between the astronauts in space and staff back on Earth as well as between the astronauts themselves. It included S-band and very high frequency (VHF) radio transmitters and receivers and a transponder. Astronauts used the VHF equipment for short-range communication and the S-band equipment to communicate across deep space. Whenever a large body – for example, the moon – was between the spacecraft and the flight crew on the ground, communication was lost.Environmental control system (ECS)
: This system controlled the spacecraft's atmospheric pressure and temperature and also managed water. It collected water from the ship's fuel cells (a useful byproduct). The ECS adjusted the temperature in the CSM through a water and glycol cooling system. The system pumped the water and glycol through coolant loops to reduce the temperature of the liquid. Then the system pumped the liquid through tubes to cool the CSM's atmosphere and electric systems, much like a liquid-cooled computer's cooling system.Earth landing system
: Housed in the CM, this system consisted of several mortar-deployed parachutes. NASA designed the Apollo spacecraft with the intention of a water landing upon re-entry. The parachutes slowed the spacecraft's descent enough to ensure the safety of the crew inside the spacecraft.
The list above just scratches the surface of the CSM's systems and controls, and doesn’t even show the lunar module systems. (Thanks to “How Stuff Works” website, a Discovery company)Check out a slideshow of photos of the Grumman Lunar Modules on the following pages:
Because the Moon moves around the Earth at more than 2,000 mph, the Lunar landing has to be calculated to coincide with the Moon's position at the end of the three-day journey to get there.