Encyclopedia Astronautica
1961.07.28 - NASA invitation to bids for Apollo prime contract


NASA invited 12 companies to submit prime contractor proposals for the Apollo spacecraft by October 9: The Boeing Airplane Company, Chance Vought Corporation, Douglas Aircraft Company, General Dynamics/Convair, the General Electric Company, Goodyear Aircraft Corporation, Grumman Aircraft Engineering Corporation, Lockheed Aircraft Corporation, McDonnell Aircraft Corporation, The Martin Company, North American Aviation, Inc., and Republic Aviation Corporation.

In the Statement of Work sent to each prospective bidder, three phases of the Apollo program were described:

Phase A:

Manned low-altitude earth orbital flights of up to two weeks' duration and unmanned reentry flights from superorbital velocities. The spacecraft designed for these missions should be capable of development for the lunar landing and return. The objectives of Phase A were to qualify the spacecraft systems and features for the lunar landing mission within the constraints of the earth orbital environment, to qualify the heat protection and other systems for the lunar mission through reentry tests from superorbital velocities, to study the physiological and psychological reactions and capabilities of human beings under extended periods in the space environment, to develop flight and ground operational techniques and equipment for space flights of extended duration, and to conduct experimental investigations to acquire information for the lunar mission. The Saturn C-1 would be used for Phase A missions.

Phase B:

Circumlunar, lunar orbital, and parabolic reentry test flights employing the Saturn C-3 launch vehicle for furthering the development of the spacecraft and operational techniques and for lunar reconnaissance.

Phase C:

Manned lunar landing and return missions using either the Nova class or Saturn C-3 launch vehicles and using rendezvous techniques for the purpose of lunar observation and exploration.

The contractor was to design and manufacture the command module, service module, and spacecraft adapter with associated ground support equipment, excluding the navigation and guidance system, research and development instrumentation, and scientific instrumentation; to design and manufacture the "test" spacecraft for use with Saturn C-1 research and development launch vehicles; to integrate the spacecraft modules and to integrate these modules with their ground support equipment and ensure compatibility of spacecraft with launch vehicle and with the ground operational support system; and to design and manufacture spacecraft mockups.

The contractor was to prepare the spacecraft for flight, man the systems monitoring positions in the ground operational support system, and support the operation of the overall space vehicle.

STG had prepared the Statement of Work, using both contractor and in- house studies. Included in the Statement of Work was a description of the major command and service module systems.

Guidance and control system

Navigation and guidance subsystem components:

- Stable platform

- Space sextant

- Radar altimeter

- Secondary inertial elements

- Computer

- Periscope

- Sun trackers

- Associated electronics

- Displays and controls

- Cabling

Stabilization and control subsystem to provide:

- Flight-path control during the thrusting period of atmospheric abort and stability augmentation after launch escape system separation

- Orientation, attitude control, and reentry stabilization and control during extra-atmospheric abort

- Stabilization of the spacecraft plus the final stage of the launch vehicle while in a parking orbit

- Stabilization and control during translunar and transearth midcourse flight

- Rendezvous and docking with the space laboratory module

- Attitude control for accomplishing landings and takeoffs from the moon and for entering and departing from lunar orbits

- Control requirements for reentry guidance

- Stabilization and control of the command module flight direction in the landing configuration, as well as the landing system suspension members

Vernier propulsion system

The system would be included in the service module to provide longitudinal velocity control not supplied by the reaction control system, mission propulsion system, or lunar landing module; and to furnish effective thrust-vector control during operation of the mission propulsion system. It would be pressure-fed, using storable hypergolic bipropellants.

Mission propulsion system

Representing the major portion of propulsion for translunar abort, lunar orbit injection and rejection, and velocity increment for lunar launch, the system would comprise a number of identical solid-propellant rocket motors and would be included in the service module.

Reaction control system

The system would provide attitude control, stabilization, ullage for the vernier propulsion system, and minor velocity corrections. For both the command and service modules, the system would be pulse-modulated, pressure-fed, and would use storable hypergolic fuel identical with that in the vernier propulsion system. The fuel tanks would be the positive expulsion type.

Launch escape system

During failure or imminent failure of the launch vehicle during all atmospheric mission phases, the system would separate the command module from the launch vehicle. The basic propulsion system would be a solid-fuel rocket motor with "step" or regressive burning characteristics.

Earth landing system

The system would consist of a ribbon drogue parachute and a cluster of three simultaneously deployed landing parachutes, sized so that satisfactory operation of any two of the three would satisfy the vertical velocity requirement. The command module would hang in a canted position from the parachute risers and be oriented through roll control to favor impact attenuation.

Structural system

In addition to fundamental load-carrying structures, the command and service modules would carry meteoroid protection, radiation protection inherent in the structure, and passive heat protection systems.

Crew systems

Included were:

- Three couches, the center one stowable

- Support and restraint systems at each duty station

- Shock mitigation devices for individual crew support and restraint systems

- Pressure suits for each crewman

- Sleeping area

- Sanitation area

Environmental control system

To provide a shirtsleeve environment in the command module, the system would consist of:

- Cabin atmosphere - an oxygen-nitrogen mixture stabilized at 7.0 psia

- Removal of carbon dioxide by lithium hydroxide

- Removal of noxious gases by activated charcoal and a catalytic burner

- Heat-exchanger water-separation system for control of temperature and humidity

- Potable water from the fuel cells

- Controls for pressure, humidity, and temperature

Electrical power system

The system would be composed of nonregenerative hydrogen-oxygen Bacon- type fuel-cell batteries carried, with their fuel supply, in the service module; silver-zinc primary batteries required during reentry and postlanding carried, with their associated fuel, distribution, and control equipment, in the command module.

Communication and instrumentation system

Communication subsystems:

- Deep-space communication

- Telemetry

- VHF transmitter and receiver

- Intercommunication system

- Near-field transceiver

- Television

- C-band transponder

- Altimeter and rendezvous radar

- Minitrack beacon

- HF/VHF recovery subsystem

- Antennas

Instrumentation subsystem:

- Sensors

- Data disposition (telemetry and onboard recorders)

- Subsystem calibration

- Auxiliary instrumentation (clock, cameras, telescope)

Scientific equipment

The equipment was unspecified but would be fitted into ten cubic feet and weigh 250 pounds.

In addition to the description of the major command and service module systems, the Statement of Work outlined the general concepts of the lunar landing module and space laboratory module.

Lunar landing module

The basic systems comprised :

Lunar touchdown system to arrest impact, support the spacecraft during its period on the moon, and provide a launching base

Guidance and control, provided by the command and service modules

Main propulsion system, for translunar velocity control and the gross velocity decrement required for lunar landing, using liquid-hydrogen - liquid-oxygen propellant

Terminal propulsion system, to provide propulsion and attitude reaction control to perform the terminal descent maneuver, including hovering and translation

Structural system, to meet the same requirements as specified for the command and service modules

Space laboratory module

The module would be used in earth orbital flights for special experiments. It would provide its own power supply, environmental control system, etc., without demand on the command and service module systems and could support two of the three Apollo crewmen except for their food and water.

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