Transtage
{{Short description|American upper rocket stage used on Titan III}}
{{Infobox rocket stage
|image = Transtage_rocket_stage.jpg
|caption = A Transtage
|country-origin = United States
|manufacturer = Martin Marietta
|rockets = Titan III
|height = {{convert|4.57|m|ft|sp=us}}
|diameter = {{convert|3.05|m|ft|sp=us}}
|mass = {{convert|12247|kg|lb}}
{{Infobox rocket/stage
| name = Engine details
|engines = 2 AJ10-138
|thrust= {{convert|8000|lbf|kN|abbr=on}} each{{cite web |url=http://www.astronautix.com/a/aj10-138.html |archive-url=https://web.archive.org/web/20161228053320/http://astronautix.com/a/aj10-138.html |url-status=dead |archive-date=December 28, 2016 |title=AJ10-138 |last=Wade |first=Mark |publisher=Encyclopedia Astronautica |accessdate=2019-07-24}}
|fuel=Aerozine 50 / {{N2O4}}
|burntime = 440 seconds
|SI = {{convert|311|isp}}
}}
}}
Transtage, given the United States Air Force designation SSB-10A, was an American upper stage used on Titan III rockets, developed by Martin Marietta and Aerojet.
History
File:Titan III Transtage burn.jpg
Transtage was developed in anticipation of a requirement to launch military payloads to geostationary orbit; a contract for development of the stage was issued on 20 August 1962.{{cite book |last=Foradori |first=Paolo |author2=Giampiero Giacomello |author3=Alessandro Pascolini |title=Arms Control and Disarmament: 50 Years of Experience in Nuclear Education |year=2017 |publisher=Palgrage Macmillan |location=London |pages=56–57 |isbn=978-3-319-62258-3}} Transtage used a pressure-fed two-chamber configuration, using Aerozine 50 fuel and nitrogen tetroxide as oxidizer; the thrust chambers were gimbaled for steering and each produced {{convert|8000|lbf|kN|adj=on|abbr=on}} of thrust.{{Cite web |date=2016-12-28 |title=Titan Transtage |url=http://astronautix.com/t/titantranstage.html |access-date=2024-04-26 |archive-url=https://web.archive.org/web/20161228032217/http://astronautix.com/t/titantranstage.html |archive-date=2016-12-28 }} The design specification required up to three restarts during the first six hours of a mission.{{cite book |last=Hunley |first=J.D. |title=The Development of Propulsion Technology for U.S. Space-Launch Vehicles, 1926-1991 |year=2007 |publisher=Texas A&M University Press |location=College Station, TX |pages=168 |isbn=978-1-58544-588-2}}
Forty-seven Titan III launches are known to have used Transtage upper stages;{{Cite web |title=Transtage |url=https://space.skyrocket.de/doc_stage/transtage.htm |access-date=2024-04-26 |website=space.skyrocket.de}} of those, three are known to have suffered launch failures.{{cite web |url=http://www.designation-systems.net/dusrm/app3/b-10.html |title=Martin Marietta SSB-10 Transtage |last=Heyman |first=Jos |date=17 March 2003 |work=Directory of U.S. Military Rockets and Missilesm Appendix 3: Space Vehicles |publisher=Designation-Systems |accessdate=2017-12-17}} The first launch, boosted by a Titan IIIA, occurred on 1 September 1964;{{Cite web |title=Transtage 1, 2, 5 |url=http://www.astronautix.com/t/transtage125.html |access-date=2024-04-26 |website=www.astronautix.com}} the Transtage failed to pressurize, resulting in premature engine cutoff, and a failure to reach orbit. The second launch, on 10 December, was successful, and all ensuing launches used the Titan IIIC launch vehicle. The last launch of a Transtage was on 4 September 1989, boosted by a Titan 34D rocket.
See also
References
{{reflist}}
{{Titan rockets}}
{{USAF space vehicles}}
{{Upper stages}}