Apollo to the Moon

About the Spacecraft

Apollo 11 Launch

Astronauts Neil A. Armstrong, Michael Collins and Edwin E. "Buzz" Aldrin Jr., inside the command module of the Apollo 11 Saturn V launch vehicle, rose from Pad 39A at Kennedy Space Center, Florida. The instant of lift-off was 9:32 a.m. EDT, July 16, 1969.

Once on the journey to the Moon, the Apollo spacecraft provided an extraordinary transport and self-sufficient place for working and living. In the extremely hostile environment of space, these spacecraft had to provide everything the astronauts required for the journey: protection, flight and work equipment, air, food, clothing, the space-equivalent of bathrooms, and more. The artifacts in this exhibition indicate the unprecedented ingenuity and planning required for a trip through space to another world.

The Apollo 11 mission had three spacecraft: the Command Module Columbia, a Service Module, and the Lunar Module Eagle. While astronauts Armstrong and Aldrin descended to the Moon in Eagle, Michael Collins remained alone in Columbia. For 28 hours he served as a communications link and photographed the lunar surface. After reclaiming Armstrong and Aldrin from the ascent stage of the Lunar Module, Columbia was the only part of the spacecraft to return to Earth.

Command Module Columbia

The Apollo 11 Command Module Columbia carried astronauts Neil Armstrong, Edwin "Buzz" Aldrin, and Michael Collins on their historic voyage to the Moon and back on July 16-24, 1969. During the mission, astronauts Armstrong and Aldrin became the first human explorers of another world.

During the journey to and from the Moon, Columbia—its interior space about as roomy as a large automobile—served as main quarters for the astronauts, a place for working and living.

The blunt-end design for the Command Module was chosen to build upon experience gained with the similarly shaped Mercury and Gemini spacecraft. The spacecraft reentered the atmosphere with its protective heat shield (the widest end of the spacecraft) facing forward. Layers of special "ablative" material on the shield were purposely allowed to burn away during reentry to help dissipate the extremely high temperatures caused by atmospheric friction.

Command Module Specifications

  • Height: 3.2 m (10 ft 7 in)
  • Maximum Diameter: 3.9 m (12 ft 10 in)
  • Weight: 5,900 kg (13,000 lb)
  • Manufacturer: North American Rockwell for NASA
  • Launch Vehicle: Saturn V

Apollo Command Module Diagram
Diagram of the Apollo Command Module interior, showing controls on the left and right sides of the module.
Apollo 11 Command Module Columbia
Command Module
This is the actual capsule that carried three astronauts to the moon and back in July 1969.

Apollo Command Module Interior
Command Module Interior
The interior of the Apollo 11 Command Module, Columbia, which served as living quarters for the astronauts throughout the journey.

Apollo 11 Hatch
Command Module Hatch
This is the hatch from the Apollo 11 Command Module. This single hatch could be opened outward in five seconds by pumping the handle to activate a pressurized nitrogen cylinder. Prior to the tragic fire in January 1967 in which three astronauts died, there were two hatches on the Apollo command module requiring 90 seconds to open.

Apollo Command Module Tools

Command Module Repair Tools

The Apollo 11 astronauts carried these tools to make minor repairs to their spacecraft. This kit was aboard the Apollo 11 command module during its lunar mission, July 16-24, 1969.

Service Module

The Service Module contained oxygen, water, and electric power for the command module. The Service Module also housed the service propulsion system—the rocket engine that put the spacecraft into lunar orbit and later boosted it back toward Earth. This module was jettisoned just before reentry into the Earth's atmosphere.

Lunar Module Eagle

After three days of travel through space, the astronauts and the three Apollo spacecraft—command module Columbia, the Service Module, and the Lunar Module Eagle—entered orbit around the Moon on July 19. During the flight to the Moon astronaut Michael Collins had repositioned the Lunar Module so that Columbia and Eagle were joined at their respective hatches. Over the next day the astronauts readied the Lunar Module and themselves for the descent to the Moon.

The Lunar Module (LM) was used for descent to the lunar surface and served as a base while the astronauts were on the Moon. A separate ascent stage, comprising the top portion of the Lunar Module, lifted the astronauts from the Moon's surface to rendezvous and dock with the command module, orbiting the Moon.

Because lunar modules were designed to fly only in the vacuum of space, they did not have to be streamlined like an aircraft or carry a heat shield for protection during reentry. Once a lunar module was launched into space, it could not return to Earth.

To learn more about the Lunar Module transposition and docking, as well as descending to the lunar surface, visit the page At the Moon.

Apollo Lunar Module
This is an actual lunar module (designation LM-2), one of 12 built for Apollo. Engineers planned to use this craft in low Earth orbit to test the techniques of separation, rendezvous, and docking with the command and service module. The second of two such test vehicles, its orbital mission was cancelled after a successful flight in an earlier mission. The spacecraft subsequently was used for ground testing.

A Two-Stage System

The lunar module had two stages:
1. A silver-and-black ascent stage, containing the crew's pressurized compartment and the clusters of rockets that controlled the spacecraft
2. A gold-and-black descent stage, similar to the ascent stage, containing a main, centrally located rocket engine and tanks of fuel and oxidizer

The descent (lower) stage was equipped with a rocket motor to slow the rate of descent to the lunar surface. It contained exploration equipment and remained on the Moon when the astronauts left. The ascent (upper) stage contained the crew compartment and a rocket motor to return the astronauts to the orbiting command module. After the crew entered the command module for the trip back to Earth, the lunar module was released and eventually crashed into the Moon.

To rejoin the command module, the astronauts fired the ascent-stage rocket engine and lifted off, leaving the descent stage on the Moon. The ascent stage met and docked with the command module in lunar orbit. The ascent stage then was programmed to crash into the Moon.

Apollo Lunar Module Cutaway
Cutaway diagram of the Apollo Lunar Module ascent stage (top) and descent stage (bottom) configurations at landing.

Heat-Maintaining Materials

The LM cutaway appears just as it would have during a moon-landing mission. Several materials cover the spacecraft to protect its inner structure from temperature and micrometeoroids. Specially designed materials maintain temperature balance inside the craft.

The black materials on parts of the LM are heat-resistant nickel-steel alloy, 0.0021072 millimeters (0.0000833 inches) thick. The black sheets absorb heat when exposed to the Sun and radiate to the blackness of deep space.

Not metal foil, these plastic films are thinly coated with aluminum, which reflects the sun's heat and insulates the spacecraft. The thin, gold-colored films are used in "blankets" of up to 25 layers. All of the plastic films protect the spacecraft from micrometeoroids.

Lunar Module Cockpit

This is a full-size mock-up of a Lunar Module cockpit, identical in appearance to the cockpits of the lunar modules used to land on the Moon. The two astronauts stand before the windows as they control the craft during descent to the lunar surface, and later, during ascent from the Moon. Sixteen rockets that can be fired automatically or manually control the attitude of the Lunar Module. An interior view of the Museum's Lunar Module-2 highlights similar features of a cockpit.

Lunar Module 2 Interior in Exploring the Moon
Apollo Lunar Module Diagram
During the Apollo program some modifications were made to the Lunar Module. This diagram shows the configuration for the modules on Apollos 15, 16, 17—the only missions to carry a Lunar Roving Vehicle. Note the compartment for storing the rover on the lower front.

Lunar Module Specifications

  • Weight (empty): 3920 kg (8650 lb)
  • Weight (with Crew & Propellant): 14,700 kg (32,500 lb)
  • Height: 7.0 m (22 ft 11 in)
  • Width: 9.4 m (31 ft 00 in)
  • Descent Engine Thrust: 44,316 Newtrons (9870 lb) maximum, 4710 Newtons (1050 lb) minimum
  • Ascent Engine Thrust: 15,700 Newtons (3500 lb)
  • Fuel: 50-50 mix of Unsymmetrical Dimethyl Hydrazine (UDMH) & Hydrazine
  • Oxydizer: Nitrogen Tetroxide
  • Prime Contractor: Grumman Aerospace Corporation

Fuel Cells

Both Gemini and Apollo spacecraft obtained electrical power from hydrogen-oxygen fuel cells. A fuel cell is like a battery. It converts energy released in a chemical reaction directly to electrical power. Unlike a storage battery, a fuel cell continues to supply current as long as chemical reactants are available or replenished (even while the cell is operating).

For space applications, fuel cells have another advantage over conventional batteries: they produce several times as much energy per equivalent unit of weight. When oxygen and hydrogen combine to form water, energy is released because the electrons in the water molecule are in a lower energy state than those in the gas molecules. In a combustion reaction, as in a rocket engine, the energy appears as heat. In a fuel cell some of it —about 50-60%—is converted directly to electrical energy. As fuel cells operate, oxygen and hydrogen combine to produce water as well as electrical power. Apollo crews used this water for drinking.

Gemini Fuel Cell Section

The Gemini spacecraft, which preceded the Apollo spacecraft, carried two hydrogen-oxygen fuel cell battery sections in its adapter/equipment section.

Each battery section contains three stacks of fuel cells with plumbing. The stacks are connected in parallel and can be switched in and out of use individually. Each stack has 32 individual cells connected in series and produces about 490 amperes at 23 to 26 volts. Maximum power output per battery section is about one kilowatt.

Manufacturer: General Electric Corporation

Gemini Fuel Cell

Gemini Fuel Cell Diagram

Apollo Fuel Cell Section

The fuel cell models displayed here contain many individual fuel cells along with the plumbing and sensors required to supply reactants and keep the cell at the proper temperature. The reactants were stored in separate tanks in liquid form to reduce space. This required keeping the oxygen at -173°C (-280°F) and at a pressure of 63.26 kilograms per square centimeter (245 pounds per square inch). Waste heat from the fuel cells was used to bring the reactants to gaseous form before they entered the cell. The Apollo fuel cell operated at a temperature of about 206°C (400°F) and the Gemini cell at about 65°C (150°F).

An Apollo spacecraft carried three hydrogen-oxygen fuel cells in the service module. Each unit contains 31 individual fuel cells connected in series and operates at 27 to 31 volts. Normal power output is 563 to 1420 watts, with a maximum of 2300 watts. Primary construction materials are titanium, stainless steel, and nickel.

Manufacturer: Pratt & Whitney Aircraft Division of United Aircraft Corporation

Apollo Fuel Cell