TransHab Concept

The TransHab program has been discontinued. The following article is for historical use.

Proposed TransHab configuration on the International Space Station.

The TransHab inflatable module was a concept proposed as a crew quarters for the International Space Station. The concept was tested but not chosen as a potential Station crew quarters, and NASA at present is no longer pursuing the concept. This section provides a historical overview of the concept, however. The concept for TransHab originated at NASA's Lyndon B. Johnson Space Center, Houston, Texas, in 1997 as a possible design for an inflatable living quarters on future Mars-bound spacecraft.

Multi-level Living Quarters

The TransHab, a design concept, could provide a large volume habitation module for the International Space Station while demonstrating its use for future transit spacecraft. The TransHab would be an inflatable living quarters as opposed to the more conventional space cylinder originally planned for the habitation module.

Benefits

The technology of inflatable structures may find uses in future space exploration beyond Earth orbit, for interplanetary spacecraft or as the ultimate “mobile home” on the Moon or Mars. In addition to benefits for the space station, a concept like TransHab may provide a valuable test of technologies that pave the way to the future in space. And, as happened in over 30,000 past space technology “spinoffs” generated since the 1960s, the development of innovative inflatable technologies for space may also find commercial uses on Earth that enhance lives and benefit the economy.

Construction

TransHab would be a unique hybrid structure that combines the packaging and mass efficiencies of an inflatable structure with the advantages of a load bearing hard structure.

Multi-Layer Inflatable Shell -- TransHab's inflatable shell consists of multiple layers of blanket insulation, protection from orbital and meteoroid debris, optimized restraint layer and a redundant bladder with a protective layer.

With almost two dozen layers, TransHab’s foot-thick inflatable shell is a marvel of innovative design. The layers are fashioned to break up particles of space debris and tiny meteorites that may hit the shell with a speed seven times as fast as a bullet. The outer layers protect multiple inner bladders, made of a material that holds in the module’s air. The shell also provides insulation from temperatures in space that can range from plus 121 degrees Celsius (plus 250 degrees Fahrenheit) in the Sun to minus 128 degrees Celsius (minus 200 degrees Fahrenheit) in the shade.

The key to the debris protection is successive layers of Nextel, a material commonly used as insulation under the hoods of many cars, spaced between several-inches-thick layers of open cell foam, similar to foam used for chair cushions on Earth. The Nextel and foam layers cause a particle to shatter as it hits, losing more and more of its energy as it penetrates deeper.

Many layers into the shell is a layer of superstrong woven Kevlar that holds the module’s shape. The air is held inside by three bladders of Combitherm, a material commonly used in the food-packing industry. The innermost layer, forming the inside wall of the module, is Nomex cloth, a fireproof material that also protects the bladder from scuffs and scratches.

Proposed TransHab configuration on the International Space Station.

Central Structural Core -- Made from lightweight carbon-fiber composite materials, the central core is a hard tunnel with a shell interface that provides three floors and dividers between various compartments. A center passageway runs the length of the module, providing access to all levels. The flooring and dividers are unfolded and extended after the module is inflated. An integral water storage tank wraps around the middle level's crew quarters to provide protection from solar radiation storms when needed. Some areas of the floor are open as passageways between levels, creating a roomy atrium effect. A pressurized docking cone consists of a common berthing mechanism and hatch, interior hatch, and an interior bulkhead.

Unpressurized Tunnel -- A bottom tunnel houses compressed air tanks used for the initial inflation of TransHab as well as other exterior equipment.