12-Man Space Station

Selected Plates From:

Development and use of a 12-Man Space Station

Speaker: C.J. Dorrenbacher – Advance Systems and Technology

McDonnell Douglas Astronautics Company

The launch vehicle places the Space Station into a 456-kilometer circular orbit at an inclination of 55 degrees. The S-II second stage is separated and deorbited into a preselected deep-ocean area. The critical systems – communications, life support, etc. – are activated and the readiness of the Space Station for manned occupancy is verified prior to committing the launch of the logistics system that will carry the Space Station crew.

The logistics system, which consists of the logistics spacecraft (or orbiter) and the crew/cargo module is launched 24 hours after the launch of the Space Station. After rendezvous some 8 hours later, the crew/cargo module separates from the logistics spacecraft and propels itself toward a docking maneuver with the Space Station. After docking, the crew enters the station, activates the remaining systems, and advises the orbiter that station operations can begin. Approximately 25 hours after initial manning, the orbiter begins its return flight to Earth.

During the first month, the crew activates all systems and readies the station for artificial-gravity test operations. The artificial-gravity module is deployed on a telescoping spoke. The combined mass of the artificial-gravity module and the station is spun around the center of gravity; the resulting centrifugal force produces a simulated gravity environment. The purpose of this operation is to explore the potential benefits and problems associated with artificial gravity.

When the artificial-gravity operations are completed, the logistics system begins delivery of additional experiments contained in modules; typically the Space Station may have three or four modules attached to it while three or four modules are flying free around it. Logistics appointments become regular (nominally. every 90 days) and experiment program is in full swing.

The Space Station is shown in a cutaway perspective. Equipment and activities are depicted as they would look upon completion of the outfitting of the station. The telescoping spoke is abbreviated for the purpose of this illustration.

During the 30-day artificial-gravity experiment, half the crew (six-men) occupies the deployed artificial-module. The men will live in the same environment as those remaining in the core module except that their effective gravity will be higher (0.7g) than it is in the core module. Some of the core will inhabit a zero-gravity cab located at the center of rotation; there they will duplicate certain tasks being performed in artificial gravity so the effects of the two enviroments can be compared. Of major interest is an evaluation of the effects of going to a zero-gravity environment to an artificial-gravity environment. The Space Station can repeat the artificial-gravity test as required: about five repetitions are assumed for design purposes.

The Space Station is 9.2 meters in diameter and about 34 meters. It consists of a core module. Further modular division is visible in that the core module contains two separate modules, each consisting of two decks; a third two-deck module comprises the habitable portion of the artificial-gravity module.

The core module contains three pressurized compartments; the compartment formed by Decks 1 and 2, the compartment formed by Decks 3 and 4, and the central tunnel. This feature ensures that a habitable environment will be available should pressure be terminated in either of the two primary compartments. The tunnel serves as the primary traffic route for men and equipment between the decks. The forward end of the core module contains the isotopes/Brayton electrical power system in an unpressurized environment and a storage compartment, which may be pressurized for access.

The core module tunnel has many functions other than that of being the main traffic artery. Contingency provisions are available should habitation of this compartment be required.

Similar to the forward half of the core module, the artificial-gravity module contains a two-deck module and a conical section containing a propulsion system to provide the spin necessary for artificial-gravity operation. This conical section also has provisions to increase the electrical power capability of the Space Station through the later addition of one or more isotope/Brayton units. Initially, Deck 6 is configured as a crew and operations facility for the artificial-gravity experiment. When the equipment used in the crew and operations facility is stowed, the volume can be converted to accommodate additional research facilities. If the need arise to accommodate a larger crew (up to 18 men), this deck can be reconverted to a crew facility. Two centrifuges occupy Deck 5.

One deck in each of the three modules is configured to support the crew. Facilities on each deck are sized to provide private quarters and eating and hygiene facilities for six men. However, the life support system will accommodate the entire crew of twelve on any deck. The layout is shown for the artificial-gravity module.

Deck 2 is dedicated to experiment activities associated with the study of various life forms in zero activity. man, animals, plants, micro organisms are all subjects for analysis. Considerations of equipment and facility commonality result in locating the dispensary and isolation ward adjacent to these laboratories.

Experiments may be accommodated either within the Space Station or in attached or free flying modules that use services provided by the Space Station. Internal experiments are either launched with the Space Station or brought up layer by the logistics system, transferred aboard, and installed; all attached and free-flying modules are delivered to orbit by the logistics system.

The Space Station contains a total of eight docking ports; these ports are of a universal design to accommodate either crew/cargo modules or attached to free-flying experiment modules. Normally, logistics modules will dock on the artificial gravity module and the aft end of the core module. The free-flying experiment modules will share the forward docking port, while all attached modules dock to the core module.

The orbiter is seen separating from the booster stage, which now prepares to return to Earth.

A typical payload for the logistics system is an experiment module leaving the cargo bay. Its propulsion system has ignited as it makes its guided way to the station.

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Image credit: McDonnell Douglas
Image source: NASA NTRS