View source for TransHab

{{short description|NASA expandable space habitat (1997–2000)}}
{{Use American English|date=May 2023}}
{{Infobox space station module
 | module                 = TransHab
 | module_image           = Transhab-cutaway.jpg
 | module_image_size      = 260px
 | module_image_caption   = A cutaway view of a TransHab concept
 | mass                   = {{convert|13154|kg|lb|0|abbr=on}}
 | length                 = {{convert|11|m|ft|0|abbr=on}}
 | diameter               = Packed: {{convert|4.3|m|ft|0|abbr=on}} <br /> Expanded: {{convert|8.2|m|ft|0|abbr=on}}
 | volume                 = Expanded: {{convert|339.8|m3|ft3|0|abbr=on}}
}}

'''TransHab''' was a program pursued by [[NASA]] in the late 1990s to develop the technology for [[Inflatable space habitat|expandable habitats]] inflated by air in space. TransHab was intended as a replacement for the existing rigid [[International Space Station]] crew [[Habitation Module]]. When deflated, inflatable modules provide an 'easier to launch' compact form. When fully inflated, TransHab would expand to {{convert|8.2|m}} in diameter (compare to the {{convert|4.4|m|adj=on}} diameter of the [[Columbus (ISS module)|Columbus ISS Module]]).<ref name="nasa20030627">{{cite web |url=http://spaceflight.nasa.gov/history/station/transhab/ |archive-url=https://web.archive.org/web/20060627190940/http://spaceflight.nasa.gov/history/station/transhab/ |url-status=dead |archive-date=2006-06-27 |title=TransHab Concept |work=NASA.gov |author=Kim Dismukes (curator) |date=2003-06-27 |access-date=2007-06-10}}</ref>

==History==
The name of the project is a contraction of ''Transit Habitat'' reflecting the original intention to design an interplanetary vehicle to transfer humans to Mars.<ref name="aiaa6105">{{cite conference |first=Kriss |last=Kennedy |title=Lessons from TransHab: An Architect's Experience |book-title=AIAA Space Architecture Symposium |date=2002 |location=Houston, Texas |id=AIAA 2002-6105}}</ref>

Considerable controversy arose during the TransHab development effort due to delays and increased costs of the [[International Space Station|ISS]] program. In 1999, the [[National Space Society]] issued a policy statement recommending that NASA continue R&D of inflatable technologies while ceasing development of a TransHab ISS module.<ref name="nss74">{{cite press release |url=http://nss.org/news/releases/release74.html |title=National Space Society Announces Policy on TransHab |publisher=National Space Society (NSS.org) |date=1999-06-10 |access-date=2007-06-10 |archive-date=2016-12-10 |archive-url=https://web.archive.org/web/20161210142022/http://nss.org/news/releases/release74.html |url-status=dead }}</ref>  Finally in 2000, despite objections from the [[White House]],<ref name="spaceref2949">{{cite press release |url=http://www.spaceref.com/news/viewpr.html?pid=2949 |title=President signs H.R. 1654, the "National Aeronautics and Space Administration Authorization Act of 2000." |publisher=Office of the Press Secretary via SpaceRef.com |author=White House |date=2000-10-30 |access-date=2007-06-10}}</ref>  House Resolution 1654 was signed into law banning [[NASA]] from conducting further research and development of TransHab. An option to lease an inflatable habitat module from private industry was included in the bill.<ref name="nasa2000">{{cite web |url=https://www.congress.gov/bill/106th-congress/house-bill/1654 |title=National Aeronautics and Space Administration Authorization Act of 2000 |publisher=Library of Congress |author=((106th Congress)) |date=2000-01-24 |access-date=2007-05-26}}</ref><ref name="nasa2000conf">{{cite web |url=http://thomas.loc.gov/cgi-bin/cpquery/T?&report=hr843&dbname=106& |title=National Aeronautics and Space Administration Authorization Act of 2000, Conference Report |publisher=Library of Congress |first=F James |last=Sensenbrenner |date=2000-09-12 |access-date=2007-06-10 |archive-date=2008-12-02 |archive-url=https://web.archive.org/web/20081202173712/http://thomas.loc.gov/cgi-bin/cpquery/T?&report=hr843&dbname=106& |url-status=dead }}</ref><ref name="spaceref2261">{{cite web |url=http://www.spaceref.com/news/viewsr.html?pid=2261 |title=Letter from NASA JSC Center Director: Actions Required to Address ISS Budget Challenges |publisher=NASA via SpaceRef.com |first=George W S |last=Abbey |date=2001-02-27 |access-date=2007-06-10}}</ref>

Since that time, the private company [[Bigelow Aerospace]] has purchased the rights to the patents developed by NASA and is pursuing a similar scheme for a private space station design.<ref name="tsr686">{{cite web |url=http://www.thespacereview.com/article/686/1 |title=Interview: TransHab developer William Schneider |work=TheSpaceReview.com |first=Dan |last=Schrimpsher |date=2006-08-21 |access-date=2007-06-10}}</ref>  The company has launched the ''[[Genesis I]]'', [[Genesis II (space habitat)|''Genesis II'']], and [[Bigelow Expandable Activity Module|BEAM]] pathfinder spacecraft, with plans for additional experimental craft culminating in their ''[[BA 330]]'' production model and the [[Bigelow Commercial Space Station]].<ref name=pm20101028>
[http://www.popularmechanics.com/science/space/news/bigelow-aerospace-ba2100-hotel Bigelow Aerospace Shows Off Bigger, Badder Space Real Estate], ''[[Popular Mechanics]]'', 2010-10-28, accessed 2010-10-30.</ref>

==Technology==
[[Image:TransHab shell cutaway.jpg|thumb|upright|Cut-away view of the TransHab multi-layer, space debris and micrometeoroid ballistic-shield.<ref>[https://web.archive.org/web/20020203112011/http://spaceflight.nasa.gov/gallery/images/station/transhab/html/s99_05362.html International Space Station Imagery], image S99-05362, "Computer Generated Still &ndash; Cutaway of the TransHab Module shell showing the various layers," 2001-08-30</ref>]]

The TransHab design called for a hybrid structure that combines the packaging and mass efficiencies of an inflatable structure with the advantages of a load-bearing hard structure.<ref name="nasa20030627"/>

===Multi-Layer Inflatable Shell===
TransHab's inflatable shell consisted of multiple layers of [[Thermal insulation|blanket insulation]], [[Ballistic vest|protection]] from [[Space debris|orbital]] and [[meteoroid]] debris, an optimized restraint layer and a redundant [[Bladder (disambiguation)|bladder]] with a protective layer.<ref name="nasa20030627"/>

TransHab's foot-thick inflatable shell design had almost two dozen layers. The layers were fashioned to break up particles of space debris and tiny meteorites that might 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 [[Outer space#Temperature|temperatures]] in [[Outer space|space]] that can range from plus 121 degrees Celsius (plus 250 degrees Fahrenheit) in sunlight to minus 128 degrees Celsius (minus 200 degrees Fahrenheit) in the shade.<ref name="nasa20030627"/>

The key to the debris protection in the design and prototype units was successive layers of [[Nextel]],<ref>[http://www.3m.com/Product/information/Nextel-Woven-Fabric.html 3M Nextel Woven Ceramic Fabric]</ref> 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 [[Terminal ballistics#Hypervelocity|shatter]] as it hits, losing more and more of its energy as it penetrates deeper.<ref name="nasa20030627"/>

Many layers deep in the shell was a layer of superstrong woven [[Kevlar]] to hold the module's shape. The air was held inside by three bladders of Combitherm,<ref>[http://www2.dupont.com/Surlyn/en_US/uses_apps/cookinfilm.html DuPont, Surlyn-resin, Combitherm-film case study]</ref> a material commonly used in the food-packing industry. The innermost layer, forming the inside wall of the module, was [[Nomex]] cloth, a [[fireproof]] material that also protected the bladder from scuffs and scratches.<ref name="nasa20030627"/>

===TransHab layout===
[[Image:TransHab level 3.jpg|thumb|Level 4 and 3]]
[[Image:TransHab crew quaters level 2.jpg|thumb|Level 2]]
[[Image:TransHab level 1.jpg|thumb|Level 1]]

TransHab was intended to be composed of four levels/floors.<ref name=nasa20030627b>{{cite web|url=http://spaceflight.nasa.gov/history/station/transhab/transhab_levels.html|archive-url=https://web.archive.org/web/20030819001416/http://spaceflight.nasa.gov/history/station/transhab/transhab_levels.html|url-status=dead|archive-date=2003-08-19|title=HSF &ndash; Transhab|publisher=NASA|access-date=2010-02-09}}</ref>

; Level 4
:The Pressurized Tunnel Area was intended to provide a passageway between TransHab and any vehicle to which it is attached. The original tunnel design had two standard International Space Station hatches and housed critical equipment required during module expansion, such as avionics and power equipment.<ref name=nasa20030627b/>

; Level 3
:Level Three was to house an exercise area with a treadmill and stationary bicycle. The design also contained a complete health care system with all types of medical and emergency equipment and a type of "space bath" area provided for body cleansing. In addition, this level contained a soft stowage area identical to level one.

:Crew Health Care Area &ndash; The design for the crew health care area incorporated two ISS Crew Health Care System racks, a Full Body Cleansing Compartment, changing area, exercise equipment (treadmill and ergometer), a partitionable area for private medical exams and conferencing, as well as an Earth-viewing window. The Earth-viewing window was to have been {{convert|51|cm|in|abbr=off}} in diameter and was located near the exercise area. The window design had four panes totaling {{convert|10.2|cm|in|abbr=off}} thick and a hard frame around each window that attaches to all layers of the shell.

:Stowage &ndash; Soft-sided cabinets was to have provided stowage for spare parts, supplies, clothing and other equipment. If built, TransHab would have doubled the stowage room available{{When|date=February 2011}} on the International Space Station.<ref name=nasa20030627b/>

; Level 2
:Crew Quarters &ndash; The crew quarters area design had six individual crew quarters, sized at {{convert|2.3|m3|ft3|sp=us}} of volume per crew quarter, and a central passageway located within the second level central core structure and water tanks. Each compartment contains a sleeping bag/sleep restraint, an area for stowing personal items, and a computer entertainment center for recreation and personal work.

:Mechanical &ndash; The mechanical room is external to the core structure and uses only half the floor space. It is acoustically and visually isolated. The other half of this area is a [[clerestory]] above the wardroom area. The mechanical room consists of an environmental control and life support system, power equipment and avionics equipment and provides return airflow from Level One and Level Three through openings.<ref name=nasa20030627b/>

; Level 1
:The first level was to house a kitchen with a refrigerator-freezer, microwave oven, water dispenser, and food preparation equipment as well as a table that seats 12, enough to allow an entire Station resident crew and replacement crew to sit together for meetings or meals. There were to be three galley racks, a large wardroom table, a soft stowage array and an Earth-viewing window identical to the window on Level 3.<ref name=nasa20030627b/>

==See also==
* [[Bigelow Expandable Activity Module]]

==References==
{{reflist}}

==External links==
{{Commons category|TransHab}}
* [http://www.hobbyspace.com/AAdmin/archive/Interviews/Systems/ConstanceAdams.html An Interview with Constance Adams], one of the architects for TransHab
* [https://www.youtube.com/watch?v=HhuGg6DyXJE Computer Animation and Inflation Test of the Original Transhab]
* [http://www.bigelowaerospace.com/ Bigelow Aerospace's official site]
* [http://news.bbc.co.uk/1/hi/technology/5173388.stm Bigelow's inflatable spacecraft]
* [https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110000798_2010047135.pdf Inflatable Structures Technology Handbook—Chapter 21: Inflatable Habitats], Draft 2000-07-05, NASA archive document.

{{Space stations}}

[[Category:Bigelow Aerospace]]
[[Category:Cancelled space stations]]