View source for Hermes (spacecraft)

{{short description|French crewed spaceplane concept (1975–1992)}}
{{Infobox spacecraft class
| name                 = Hermes
| image                = Hermes Spaceplane ESA.jpg
| image_caption        = Artist's impression of Hermes
| designer             = [[CNES|Centre National d'Études Spatiales]]
| country              = France
| spacecraft_type      = [[Spaceplane]]
| design_life          = 30 to 90 days
| launch_mass          = {{cvt|21000|kg}}
| payload_capacity     = {{cvt|3000|kg}}
| crew_capacity        = Three
| status               = Cancelled
| next                 = [[SOAR (spaceplane)|SOAR]]
}}

'''Hermes''' was a proposed [[spaceplane]] designed by the French [[CNES|Centre National d'Études Spatiales]] (CNES) in 1975, and later by the [[European Space Agency]] (ESA). It was superficially similar to the American [[Boeing X-20 Dyna-Soar]] and the larger [[Space Shuttle]].

In January 1985, CNES proposed to proceed with Hermes development under the auspices of the ESA.<ref>Martin Bayer, ''Hermes: Learning from our mistakes'', Space Policy, Volume 11, Number 3, August 1995, pp. 171-180(10)</ref><ref>{{Cite web|url=https://www.space.com/28497-europe-ixv-mini-space-shuttle-launch.html|title=Europe's Experimental Mini-Space Shuttle to Launch Wednesday|first=Elizabeth|last=Howell|date=February 9, 2015|website=Space.com}}</ref> Hermes was to have been a crewed spaceflight program launched by an [[Ariane 5]] [[launch vehicle]]. In November 1987, the project was approved for pre-development from 1988 to 1990, after which authorisation for full development was required. However, the project experienced numerous delays and funding issues.

In 1992, Hermes was cancelled due to high cost and unachievable performance, as well as a partnership with the [[Roscosmos|Russian Aviation and Space Agency]] (RKA) which reduced the need for an independent spaceplane. As a result, no Hermes shuttles were ever built. During the 2010s, it was proposed to resurrect the Hermes vehicle as a [[Reusable launch system|partially reusable]] [[Air launch to orbit|air-launched]] [[spaceplane]] [[Launch vehicle|launch system]], known as [[SOAR (spaceplane)|SOAR]].

==Development==
===Origins===
During the 1960s and 1970s, there was increasing recognition by European nations that more international cooperation would be necessary for large space projects.<ref name = "moxon 24"/> In 1973, the [[European Space Research Organisation]] (ESRO) — a precursor to the [[European Space Agency]] (ESA) — commenced development of a heavy [[expendable launch system]] later named the [[Ariane (rocket family)|Ariane]]. The French space agency [[CNES|Centre National D'études Spatiales]] (CNES), desired greater autonomy to avoid overreliance upon [[NASA]], and envisaged a European-built human-capable space vehicle that would operate in conjunction with other ESA assets such as Ariane.<ref name = "moxon 24">Moxon, Warwick and Sedbon 1985, p. 24.</ref>

In 1976, CNES commenced studies into a crewed version of Ariane.<ref name = "moxon 25"/> Two different concepts included a capsule and a glider. In 1983, CNES opted to focus on a space plane that would deliver greater convenience, comfort, and cost-effectiveness.<ref name = "moxon 25"/> A space plane would simplify recovery by having the necessary cross-range manoeuvrability to reach a given point on the Earth within a single day, while providing for a less challenging re-entry environment for the crew and payload. Reusability would also reduce the cost of successive missions.<ref name = "moxon 25"/> Critical technologies identified included [[thermal insulation|thermal protection]], [[Environmental control system (aircraft)|environmental control]]s, [[life support system]]s, [[aerodynamics]], and power.<ref name = "moxon 25 26">Moxon, Warwick and Sedbon 1985, pp. 25-26.</ref>

During the mid-1980s, in addition to the [[Columbus Man-Tended Free Flyer]] (an independent European [[space station]]) and the [[Ariane 5]] heavy launch vehicle,<ref>{{Cite web|url=https://books.google.com/books?id=_K_cmWVA0xEC&dq=%22Hermes%22+spacecraft+-wikipedia&pg=PA32|title=Europe and Asia in Space|date=October 15, 1991|publisher=USAF Phillips Laboratory|via=Google Books}}</ref> CNES championed the development and production of the ''Space Shuttle'' as a European initiative akin to the reusable space vehicle programs of the Soviet Union's [[Buran (spacecraft)|Buran]] and the US [[Space Shuttle]].<ref name = "moxon 24"/>

===Selection===
[[File:10.10.1987. D. Baudis. J. Chaban Delmas. Blanc à la mairie. expo. (1987) - 53Fi3697 (cropped).jpg|thumb|[[Jacques Chaban-Delmas]] and [[Dominique Baudis]] in front of a full-scale mock-up in [[Toulouse]], October 1987]]

On 18 October 1985, CNES appointed French [[aerospace]] company [[Aérospatiale]] as the primary contractor for Hermes, the name that had been given to the spacecraft. French aircraft manufacturer [[Dassault Aviation|Dassault-Breguet]] was awarded responsibility for the aerodynamic and aerothermal aspects of the design.<ref name = "moxon 24"/> [[Arianespace]] was responsible for the Ariane 5 launcher and a strong candidate to manage operation of the infrastructure for ''Hermes''.<ref name = "moxon 24"/>

On 25 October 1985, the proposal for Hermes was presented to the partner nations of the ESA.<ref name = "moxon 24"/> A deadline of March 1987 was set for the 'Europeanisation' of the programme, under which portions of work for Hermes was assigned.<ref>{{Cite web|url=https://books.google.com/books?id=KNZVAAAAYAAJ&dq=%22Hermes%22+spacecraft+-wikipedia&pg=RA48-PA6|title=The Week in Germany|date=October 15, 1986|publisher=German Information Center.|via=Google Books}}</ref> The work share was attributed 15% to [[West Germany]], 13% to Italy, 7% to Belgium, 5% to the Netherlands, 4% each to the United Kingdom, Spain, and Sweden, and 2% or less to Switzerland, Austria, Denmark and Ireland. Potential participation by Norway and Canada was mooted.<ref name = "moxon 24"/> France held a 50 percent share of the work, although CNES was open to further redistribution of the work dependent upon individual partners increasing their stake in the programme. Early on, there was optimism that securing the funding from ESA members to proceed would not be difficult.<ref name = "moxon 24"/>

In November 1987, the ESA issued its approval. As envisaged, by 1995 Hermes would enable the ESA to service the planned Columbus Man-Tended Free Flyer (MTFF)<ref>{{Cite web|url=https://books.google.com/books?id=qfBTAAAAMAAJ&dq=%22Hermes%22+spacecraft+-wikipedia&pg=RA3-PA174|title=Space Station Systems: Supplement|date=October 15, 1986|publisher=Scientific and Technical Information Branch, National Aeronautics and Space Administration|via=Google Books}}</ref> (the MTFF was restructured and ultimately manufactured as the [[Columbus (ISS module)|Columbus module]] of the [[International Space Station]]).<ref name = "moxon 24"/> Development of Hermes was to proceed in two phases:<ref name = "moxon 24"/>

===''Phase 1: Study and pre-development.''===
Phase 1 was scheduled to end in 1990. Its plans called for the capability to lift 6 astronauts and {{cvt|4,550|kg|lb}} of cargo, but after the [[STS-51-L|Challenger]] disaster, an ejection capacity was added to give astronauts at least a small chance of survival in case of catastrophe. Accordingly, the six seats were curtailed to three regular [[ejection seat]]s, which were chosen over an ejectable crew [[space capsule|capsule]] that would have offered an escape option at heights above {{cvt|28|km|mi}}. The cargo capacity was reduced to {{cvt|3,000|kg|lb}}. ''Hermes'' would not be able to place objects into [[orbit]] because its cargo hold could not be opened; that option was abandoned due to weight concerns.{{cn|date=March 2025}}

Although ''Hermes'' was originally viewed as fully reusable (up to 30 re-entries before major service), the limited capacity of the Ariane 5 launcher forced it to leave the Resource Module in orbit. A new resource module would be attached to the ''Hermes'' and the entire structure would be launched again.

Phase 1 was not completed until the end of 1991 and by then the political climate had changed considerably. The [[Iron Curtain]] had been lifted and the [[Cold War]] was ending. As a result, ESA commenced a year-long "reflection" period to determine whether it still made sense for Europe to build its own space shuttle and space station or if new partners could be found to share cost and development. Officially, Phase 1 completed at the end of 1992.

===''Phase 2: Final development, manufacture & initial operations.''===
Phase 2 never  began, after ESA and the [[Russian Aviation and Space Agency]] (RKA) agreed to cooperate on future launchers and a replacement space station for [[Mir]]. Economic concerns prevented RKA from participating in a future launcher program, but at this point ESA's crew transport needs were reoriented towards the capsule system (as opposed to the glider system of ''Hermes'') called for by the joint Russian/European designs.

When both Russia and ESA joined with [[NASA]] to build the [[International Space Station]], the need for a European crew transport system was eliminated because Russian and American needs were already satisfied. Accordingly, ESA  abandoned the ''Hermes'' project.

==Design==
Hermes was intended as a [[reusable launch system]] to transport [[astronaut]]s and moderate-size cargo payloads into [[low Earth orbit]] (LEO) and back.<ref name = "moxon 24"/> Hermes bears a resemblance to other [[reusable launch vehicle]]s such as the [[Space Shuttle]]. However, unlike the Space Shuttle, Hermes could not carry heavy cargoes as that role was to be performed by the uncrewed [[Ariane 5]].<ref name = "moxon 24 25">Moxon, Warwick and Sedbon 1985, pp. 24-25.</ref> Hermes was envisioned to transport a maximum of three astronauts<ref>{{Cite journal|url=https://ui.adsabs.harvard.edu/abs/1990sis..symp.....B|title=Hermes avionics|first1=Alain|last1=Blanc|first2=Alain|last2=Mosnier|date=September 1, 1990|journal=AIAA and NASA, 2nd International Symposium on Space Information Systems|bibcode=1990sis..symp.....B|via=NASA ADS}}</ref> along with a {{cvt|3,000|kg|lb}} pressurized payload. The launch weight would be up to {{cvt|21,000|kg|lb}}, the practical upper limit of an extended Ariane 5 launcher.

Hermes was to be launched as the upper stage of the Ariane 5. Prior to the 1986 redesign, ''Hermes'' was a single spaceplane containing (front to back) a crew compartment for six, an airlock, an unpressurized cargo hold similar to Buran's and the Shuttle's, and a service module.<ref>{{Cite web|url=http://www.capcomespace.net/dossiers/espace_europeen/hermes/1985.htm|title = Hermès l' avion spatial français 1985}}</ref> After the 1986 ''Challenger'' accident it was substantially redesigned. <ref>{{Cite web|url=http://www.capcomespace.net/dossiers/espace_europeen/hermes/1986_87.htm|title = Hermès l' avion spatial français 1986-1987}}</ref> The crew cabin shrank to carry three astronauts, with the cargo hold pressurized and unable to carry or retrieve satellites. ''Hermes'' now consisted of two separate sections: the vehicle itself and a cone-shaped Resource Module having a docking mechanism attached to the vehicle's rear, which was detached and discarded prior to [[Atmospheric entry|re-entry]]. Only the crewed vehicle would re-enter Earth's atmosphere and be re-used. The Resource Module and the launcher would be expended.<ref name = "moxon 24 25"/> When launching the Hermes, the Ariane 5 would have had its upper stage replaced by the space plane and an adaptor to mate the vehicle to the main [[cryogenic]] stage. The equipment bay of the launcher would also be removed and the spaceplane would perform all guidance and control functions.<ref name = "moxon 25">Moxon, Warwick and Sedbon 1985, p. 25.</ref> The development of the Ariane 5 was strongly influenced by the requirements of ''Hermes'', such as the extra aerodynamic loads along with an increased reliability factor of 0.9999, while retaining minimal impact on the launcher's commercial competitiveness on non-''Hermes'' missions.<ref name = "moxon 25"/>

In comparison to the Space Shuttle, ''Hermes'' was substantially smaller.<ref name = "moxon 25"/> It did not share the [[Wing configuration#Chord variation along span|ogival planform]] of the Shuttle, instead opting for a highly-[[swept wing|swept]] [[delta wing]] complete with [[wingtip device]]s, similar to the proposed [[Boeing X-20 Dyna-Soar]] spacecraft. Like the Shuttle, the pressurised cabin could seat more than five people, two of whom would serve as pilots, while the unpressurised aft cargo bay would have been fitted with large doors spanning the length of the bay along the fuselage.<ref name = "moxon 25 27">Moxon, Warwick and Sedbon 1985, pp. 25, 27.</ref> The vehicle would have been powered by a pair of 2,000N-thrust liquid propellant [[rocket motor]]s identical to those used on the L4 low-energy upper stage of the Ariane 5.<ref name = "moxon 25"/>

Aerodynamic control would have been provided via a total of seven [[flight control surfaces]], the wingtip [[rudder]]s, [[trailing edge]] [[elevon]]/[[air brake (aeronautics)|air brake]]s, and a body-mounted [[Flap (aeronautics)|flap]]; these surfaces would have been controlled via quadruplex-redundant [[Fly-by-wire|digital flight control]]s and actuated via triplex-redundant hydraulics.<ref name = "moxon 25"/> Mission management would have been performed via three general-purpose computers, a monitoring computer, and three digital [[Bus (computing)|databus]]es. Electrical power was to be provided by a [[motor]] that would have used [[liquid oxygen]]-[[liquid hydrogen]] along with ten US-built [[fuel cell]]s.<ref name = "moxon 25 26"/> The environmental control and life support systems supply [[Cabin pressurization|pressurisation]] of the cabin, along with air, water, and warmth, to support the crew for a maximum of 40 days, although may have been potentially extendable to enable 90 day missions. ''Hermes'' could have operated autonomously for up to one month, and would be able to remain docked with an orbiting space station for a maximum of 90 days.<ref name = "moxon 25 26"/>

According to CNES, ''Hermes'' would have been subject to more extreme re-entry conditions than the Space Shuttle due to its smaller size exposing the vehicle to higher aerothermal pressures.<ref name = "moxon 26">Moxon, Warwick and Sedbon 1985, p. 26.</ref> The baseline thermal protection,<ref>{{Cite journal|url=https://ui.adsabs.harvard.edu/abs/1988STIA...8929274B|title=Phenomena encountered by the thermal protection materials during Hermes reentry|first1=M. P.|last1=Bacos|first2=M.|last2=Parlier|date=December 1, 1988|journal=NASA STI/Recon Technical Report A|volume=1988-122|pages=29274|bibcode=1988STIA...8929274B|via=NASA ADS}}</ref> was to withstand temperatures of 1,400-1,600&nbsp;°C for a minimum of 20 minutes and studied by Dassault and SEP, would have consisted of [[carbon]] elements with an anti-[[oxidant]] coating applied to portions of the nose and [[leading edge]]s of the wings, while thermal tiles were to have covered the underside of the wing and fuselage.<ref name = "moxon 26"/> These tiles would have employed thin, reinforced [[ceramic]]-carbon honeycomb [[composite material|composite]] insulating layers separated by thin sheets of metal [[alloy]] to reflect the heat; an alternative concept for the tiles would have employed higher metallic portions in place of ceramics. The upper surfaces of the vehicle would have been subject to less heat than the lower surfaces, and used flexible blanket-like low-density, glassfibre-ceramic layers.<ref name = "moxon 26"/>

The shape of Hermes had been effectively frozen by November 1985.<ref name = "moxon 26"/> It was refined by subsonic [[wind tunnel]] testing in the Onera, constrained by the requirements of subsonic flight. In order to gather valuable data in the face of Europe's lack of experience, Dassault proposed validating the aerodynamic properties of the vehicle by completing a 1.4-[[tonne]], 1-scale aerothermal demonstrator, named ''Maia'', to be launched by an [[Ariane 4]] for re-entry studies.<ref name = "moxon 26 27">Moxon, Warwick and Sedbon 1985, pp. 26-27.</ref>

===Mission profiles and infrastructure===
Four typical missions were projected for ''Hermes'':
* Hosting onboard experiments while in an equatorial {{cvt|800|km|mi}} altitude orbit
* Flights to NASA's [[Space Station Freedom|space station ''Freedom'']] at a 28.5° inclination orbit 
* Flights to ESA's [[Columbus Man-Tended Free Flyer|space station ''Columbus'']] at a 60° orbit.
* Flights to ESA's uncrewed [[remote sensing]] ''Polar Platform'' at a 98° {{cvt|500|km|mi}} orbit

After each mission, Hermes would be refurbished at a dedicated facility in Europe.<ref name = "moxon 27"/> Around 40 days prior to a launch date, the vehicle would be transported on a specially-modified [[Airbus A300]] airliner to its launch site in [[Kourou]], [[French Guiana]], where it would be integrated with its payload and installed atop an Ariane 5 rocket prior to being transferred to the launch pad. Mission control was to be based at [[Toulouse]], France.<ref name = "moxon 27"/> During a typical mission, communications and tracking would have been performed by a planned European network of data relay satellites with coverage across 75% of a Hermes mission at a 28.5° orbit at an altitude of {{cvt|400|km|mi}}.

Following a mission, Hermes would land at [[Istres-Le Tubé Air Base]] near [[Istres]].<ref name = "moxon 27"/> Other potential landing sites were mooted, including [[Guiana Space Centre]], [[Martinique Aimé Césaire International Airport]] on the island of [[Fort de France]] and unspecified airstrips in [[Bermuda]]. In the event of an aborted launch during the first 84 seconds, ''Hermes'' would be able to return to Kourou. A later abort would likely necessitate a water landing in the [[Atlantic Ocean]], after which the vehicle would need to be retrieved by a recovery ship. Other emergency landing strips were to be designated, dependent upon the specifics of each mission.<ref name = "moxon 27">Moxon, Warwick and Sedbon 1985, p. 27.</ref>

==Mockups and models==
[[File:29.09.1987. F. Mitterrand à la mairie et au SITEF. (1987) - 53Fi3687.jpg|thumb|Hermes mockup behind French president [[François Mitterrand|Mitterrand]]. Photo taken at Toulouse in 1987.]]
[[File:Sevilla Expo 92-Projecto ESA-1992 05 05.jpg|thumb|Hermes mockup on display during the [[Seville Expo '92|Sevilla Expo 92]]]]
A full scale mockup was built in 1986,<ref name="auto">{{Cite web|url=http://www.capcomespace.net/dossiers/espace_europeen/hermes/expo.htm|title=Hermès l' avion spatial français 1991-1993|website=www.capcomespace.net}}</ref> and was shown in 1987 at [[Musée de l'air et de l'espace|Le Bourget]] in May, followed by [[Madrid]] in September and [[Toulouse]] during October - November. In 1988 the mockup was shown at [[Strasbourg]] in Abril, [[Hanover]] in May, and [[Bordeaux]] in December. With the end of the project in 1993, this mockup was transferred to [[ENSICA]] (''École nationale supérieures d'ingénieurs de construction aéronautique'') in 1996. In 2005 it was brought to [[Musée de l'air et de l'espace|Le Bourget]] to await a possible restoration project.<ref name="auto"/>

A 1/7 scale model built by [[EADS]] has been on display since 2002 at the [[Bordeaux–Mérignac Airport]].<ref name="auto"/>

==In media==
* A 1994 [[The Simpsons]] episode called ''Deep Space Homer'' features a Hermes inspired shuttle design.<ref>{{Cite web|url=https://jalopnik.com/the-mystery-of-the-space-shuttle-in-that-simpsons-episo-1797280453|title=The Mystery Of The Space Shuttle In That Simpsons Episode Where Homer Went To Space|website=Jalopnik|date=27 July 2017 }}</ref>
* The 2015 film ''[[The Martian (film)|''The Martian'' ]]'' features a ship named ''Hermes'', although the design is radically different from the shuttle design in real life, and is designed for interplanetary travel.
* The 2017 film ''[[Valerian and the City of a Thousand Planets]]''<nowiki>'</nowiki>s novelization mentions ''Hermes'' as the shuttle used by ESA during its first expedition to the [[International Space Station]] (identified as "Alpha").

==See also==
* {{annotated link|Hopper (spacecraft)|Hopper}}
* {{annotated link|Intermediate eXperimental Vehicle}}
* {{annotated link|SOAR (spaceplane)|SOAR}}
* {{annotated link|Dream Chaser}}

==References==
===Citations===
{{Reflist}}

===Bibliography===
{{refbegin}}
* Van den Abeelen, Luc. [https://www.springer.com/gp/book/9783319444703 "Spaceplane HERMES - Europe's Dream of Independent Manned Spaceflight."].
* Moxon, Julian, Graham Warwick and Gilbert Sedbon. [https://www.flightglobal.com/pdfarchive/view/1985/1985%20-%203142.html "Hermes: France forces the pace."] ''Flight International'', 30 November 1985. pp.&nbsp;24–27.
{{refend}}

==External links==
* [https://web.archive.org/web/20160820192213/http://www.astronautix.com/h/hermes.html ''Hermes'' at Astronautix.com]
* [http://www.aerospaceguide.net/hermes.html ''Hermes'' at Aerospaceguide.net]
* [http://www.pyperpote.tonsite.biz/listinmae/index.php/les-appareils-en-reserve/les-reserves-du-musee-de-l-air/333-hermes-avion-spatial-europeen 1:1 Mockup photos, including cockpit]
* [http://www.capcomespace.net/dossiers/espace_europeen/hermes/index.htm HERMES, l' avion spatial inachevé...]

{{European human spaceflight}}
{{Reusable launch systems}}
{{Spaceplanes}}
{{Ariane}}

[[Category:Proposed European Space Agency spacecraft]]
[[Category:Crewed spacecraft]]
[[Category:Cancelled spacecraft]]
[[Category:Spaceplanes]]