View source for Engineering:BAC Mustard

{{short description|Re-usable space launch system}}
{{Infobox rocket
<!----Image (optional)---->
|image   =  <!--image filename (omit "Image:" prefix), required-->
|imsize  =  <!--Size of image (omit "px" suffix), optional, defaults to 270px-->
|caption =  <!--caption, optional-->
<!----Core parameters (required)---->
|name           =  Multi-Unit Space Transport And Recovery Device
|function       =  <!--Purpose of the rocket, required-->
|manufacturer   =  British Aircraft Corporation (BAC)
|country-origin =  UK
<!----Costs (optional)---->
|cpl      =  <!--cost per launch, required-->
|cpl-year =  <!--year when this cost applied, required-->
|alt-cpl  =  <!--cost in alternative currency, optional-->
<!----Dimensions (required)---->
|height       =  {{convert|118|ft|0|in|m}}
|diameter     =  {{convert|13|ft|1|in|m}}
|mass         =  {{convert|424270|kg|lb}}
|stages       =  2
<!----Payloads (optional)---->
|capacities =  <!--insert one of the following templates for each payload:-->
  {{Infobox rocket/Payload
  |location =  
  |kilos    =  {{convert|2268|kg|lb}}
  }}
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|family      =  <!--rocket family, optional-->
|derivatives =  <!--derived rockets, optional-->
|comparable  =  <!--similar, unrelated rockets, optional-->
<!----Launch history (required)---->
|status   =  Cancelled
|sites    =  <!--launch centres and pads, required-->
|launches =  0
|success  =  <!--total successful launches, optional-->
|fail     =  <!--total failed launches, optional-->
|partial  =  <!--total number of launches resulting in partial failure (e.g. incorrect orbit but still usable), optional-->
|other_outcome =  <!--number of launches with unknown outcomes (or in progress), optional-->
|first    =  <!--date of first flight, optional-->
|last     =  <!--date of final flight, optional-->
|only     =  <!--launch date if only one was launched, optional-->
|payloads =  <!--associated payloads, optional-->
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|stagedata    =  <!--insert one of the following templates for each stage:-->
  {{Infobox rocket/Stage
  |type       =  <!--booster or stage (must be in lower case)-->
  |diff       =  <!--variant of rocket this is used on, optional-->
  |stageno    =  <!--position of stage in rocket, spelled out (e.g. First, Second, etc.), required-->
  |name       =  <!--name of the stage/booster, optional-->
  |number     =  <!--number of boosters, required if type = booster-->
  |length     =  <!--length of a single booster/stage in metres, optional, use {{convert}}-->
  |diameter   =  <!--diameter of a single booster/stage, optional in metres, use {{convert}}-->
  |empty      =  <!--empty mass of a single booster/stage in kilograms, optional, use {{convert}}-->
  |gross      =  <!--gross (fuelled) mass of a single booster/stage, optional-->
  |engines    =  1
  |thrust     =  {{convert|2150|kN|lbf}}<ref>{{cite web | url=http://www.astronautix.com/m/mustard.html | title=Mustard }}</ref>
  |total      =  <!--total thrust for all boosters in kN, optional, use {{convert}}-->
  |SI         =  405
  |burntime   =  215 seconds
  |fuel       =  [[Physics:Liquid oxygen|LOX]]/[[Chemistry:Liquid hydrogen|LH2]]
  }}
}}

The '''Multi-Unit Space Transport And Recovery Device''' or '''MUSTARD''', usually written as '''Mustard''', was a reusable launch system concept that was explored by the British Aircraft Corporation (BAC) during the mid-1960s.

Mustard was intended to operate as a [[Astronomy:Multistage rocket|multistage rocket]], the individual stages comprising near-identical [[Astronomy:Spaceplane|spaceplane]] modules. These planes, or stages, were [[Physics:Hypersonic|hypersonic]] vehicles, capable of flying at speeds in excess of five times the speed of sound.<ref name = "bae summ"/> Following a vertically standing launch, each stage was to progressively separate during the ascent, after which they would individually fly back towards a suitable landing strip. The final spaceplane was to be capable of attaining such an altitude that it would be able to achieve a sub-orbital trajectory before also performing a controlled return. Following a conventional landing, all of the stages were intended to be reused multiple times. It was projected that Mustard was suitable for launching payloads weighing as much as {{convert|5000|lb|kg|order=flip|abbr=on}} into [[Physics:Orbit|orbit]].

The concept originated from studies performed by British manufacturing conglomerate [[Company:English Electric|English Electric]], who had drawn inspiration from an American proposal, the Douglas Astro, which was proposed in 1962.<ref>{{Cite web|url=http://www.astronautix.com/d/douglasastro.html|archive-url=https://web.archive.org/web/20161228051941/http://astronautix.com/d/douglasastro.html|url-status=dead|archive-date=28 December 2016|title=Douglas Astro|website=www.astronautix.com|access-date=25 January 2021}}</ref> Throughout the 1960s, the Mustard project was refined and prepared for programme launch. However, financing for the initiative was not forthcoming from the British government and the concept ultimately languished following the completion of the last major design study in early 1967. According to BAC's successor company BAE Systems, the projected cost of completing Mustard's development had been estimated as being between 20 and 30 times cheaper than the conventional expendable launch system used for the American [[Astronomy:Apollo program|Apollo program]].<ref name = "bae summ">[http://www.baesystems.com/en-uk/feature/1960s-lsquothunderbirdsrsquo-projects-brought-to-life "1960's 'Thunderbirds' projects brought to life."] ''BAE Systems'', Retrieved: 2 January 2019.</ref> The knowledge and expertise from Mustard was applied in various other avenues, the most prominent being the [[Engineering:HOTOL|HOTOL]] spaceplane programme during the 1980s.

==History==
===Origins===
During the 1940s and 1950s, the United Kingdom had undertaken numerous independent space-related ventures, such as the [[Engineering:Black Knight (rocket)|Black Knight]] [[Physics:Ballistic missile|ballistic missile]] programme and the abortive Black Arrow [[Astronomy:Satellite|satellite]] launcher.<ref name = "hill 188">Hill 2001, p. 188.</ref> While the ambitions of these programmes had been tempered both by cost and a political desire to collaborate with other [[Organization:Commonwealth of Nations|Commonwealth]] and Western nations, such as the Europa launcher, Britain retained a considerable interest in the pursuit of various space-related technologies.<ref name="hill 13">Hill 2001, p. 13.</ref> The field of re-usable space vehicles was no exception to this interest, British manufacturing conglomerate [[Company:English Electric|English Electric]] had undertaken preliminary work on the topic at their facility in Warton, Lancashire, as part of a government-sponsored series of wider studies into high-speed vehicles and sub-orbital [[Astronomy:Spaceplane|spaceplane]]s. During 1960, the [[Earth:Aerospace|aerospace]] activities of English Electric merged with those of multiple other firms in the formation of the British Aircraft Corporation (BAC). The new entity continued its sponsored research into these concepts.<ref name = "newsci86"/>

According to author Nigel Henbest, one of BAC's research teams, headed by engineer Tom Smith, Chief of the Aerospace Department at BAC,<ref name=flight_international_EST>{{cite web |url=http://www.flightglobal.com/pdfarchive/view/1966/1966%20-%200816.html |title="''Flight International'', 24 March 1966, p. 473. Economical Space Transport." |archive-url=https://web.archive.org/web/20160804020458/http://www.flightglobal.com/pdfarchive/view/1966/1966%20-%200816.html |archive-date=4 August 2016}}</ref> that was initially investigating supersonic and [[Physics:Hypersonic|hypersonic]] flight problems, became interested in the application of such a vehicle for space-related activities.<ref name = "newsci86"/> The team compared their performance estimates of a winged reusable launch vehicle against conventional [[Astronomy:Multistage rocket|multistage rocket]]s, determining that the approach was not cost-effective, largely due to it requiring different rockets to power each stage. Instead, by simplifying the launcher to use near-identical winged vehicles, considerable cost savings would then be achievable both in terms of its development and manufacture.<ref name = "newsci86"/> Associated costs would have been further reduced by all of the elements being reusable and without any need for post-mission refurbishment, only requiring refuelling. Furthermore, the scale of the vehicles could be increased or decreased to produce launch vehicles to suit virtually any weight and thrust requirements.<ref name = "newsci86"/>

It has been claimed{{by whom|date=July 2019}} that from an early stage, BAC's space-related research was being influenced by foreign space programmes, most significant of these being the United States; reportedly, the company engaged in detailed studies of various transatlantic projects and proposals. One particular proposed vehicle, the Douglas Astro, is said{{by whom|date=July 2019}} to have impressed British researchers; around the beginning of 1964, the Astro was adopted as a conceptual starting point for BAC's own clustered design, which the company came to refer to as the ''Multi-Unit Space Transport And Recovery Device'' or ''MUSTARD''; however, in common parlance, this moniker was usually written simply as ''Mustard''. In the most intensely-studied design, Mustard was to have weighed roughly 420 tonnes prior to launch, and be capable of delivering a payload of three tonnes into a [[Astronomy:Geostationary orbit|geostationary earth orbit]] (GEO).<ref name = "newsci86"/>

===Stall and termination===
During 1964, the design of Mustard had reached the point where it was effectively complete.<ref name = "newsci86"/> However, Smith acknowledges that in order to have continued the project through to the manufacturing stage, several billion [[Finance:Pound sterling|pound]]s of investment would have been required, the financing of which was neither budgeted nor planned for by any entity. Writing for the scientific periodical ''New Scientist'', author Nigel Henbest commented that it was unlikely that Britain could pursue the development of Mustard alone, but also suggested that there was potential value for the platform if organised as a multinational European venture, similar to the conventional Europa and [[Engineering:Ariane (rocket family)|Ariane]] launchers.<ref name = "newsci86"/>

In early 1967, the last major design study on the topic was drawn up, after which the project was continued at a lower level until work on Mustard was finally terminated in 1970 by the British government, who had decided to participate in the new American post-Apollo project instead. Accordingly, a number of key Mustard project staff had spent the first two years of the 1970s overseas at North American Rockwell, where they contributed to the initial study which would eventually lead to the US [[Engineering:Space Shuttle|Space Shuttle]]. Around this time, the prospect of collaboration is said to have faded and, in the absence of significant interest from the British government, the Mustard project was effectively terminated.

In early 1977, BAC was itself later merged with rival Hawker Siddeley to form British Aerospace (B.Ae) and when the reusable [[Engineering:HOTOL|HOTOL]] spaceplane project arose in 1984, the project team was relocated to Warton, where they took advantage of the expertise that had been accumulated during the earlier Mustard project.<ref name="sharp2016">Sharp 2016, {{page needed|date=July 2019}}.</ref><ref name = "newsci86"/> Writing of Mustard's cancellation, Henbest wrote that the absence of "political courage" had been largely responsible for the failure of the venture to become reality; furthermore, if further research had been financed by the Ministry of Aviation, then Britain may have been able to play a larger role in other space programmes, such as the American [[Engineering:Space Shuttle|Space Shuttle]].<ref name = "newsci86">Henbest, Nigel. [https://books.google.com/books?id=KWmKGnwBffwC "How Britain missed out on MUSTARD."] ''New Scientist'', Vol. 110, No. 1509. ISSN 0262-4079. 22 May 1986, p. 60.</ref>

==Design==
===Modules===
Mustard was a modular reusable space launch system, comprising multiple copies of a single vehicle design, each of which was configured for a different role as a booster stage or an orbital spaceplane. The core vehicle design resembled the basic layout of the Douglas Astro, both being delta-winged reusable vehicles, as would the later American Space Shuttle. Furthermore, all three functioned as vertically launched rockets and used integral wings so that they could land horizontally, akin to an aeroplane.<ref name="sharp2016"/><ref>"BAC MUSTARD Project Artwork Archive", ''Britain in Space'', {{Cite web |url=http://www.britain-in-space.co.uk/info/pix-archive/mustard.html |title=BAC MUSTARD (British Aircraft Corporation: Multi Unit Space Transport and Recovery Device) Project - Artists Impressions - Britain in Space |access-date=8 September 2012 |archive-url=https://web.archive.org/web/20120926000930/http://www.britain-in-space.co.uk/info/pix-archive/mustard.html |archive-date=26 September 2012 |url-status=dead }}</ref><ref name=flight_international_STfE>{{cite web |url=http://www.flightglobal.com/FlightPDFArchive/1966/1966%20-%200663.pdf |title="''Flight International'', 10 March 1966, p. 402.Space Transporters for Europe?" |archive-url=https://web.archive.org/web/20160826224835/https://www.flightglobal.com/FlightPDFArchive/1966/1966%20-%200663.pdf |archive-date=26 August 2016}}</ref>

The design evolved through a total of fifteen proposed variants or schemes, each typically comprising a deep-keeled lifting-body airframe with delta wings in a smooth [[Engineering:Blended wing body|blended wing body]] layout, with twin tail fins rising from the [[Engineering:Wing tip|wing tip]]s and canted outwards. Some early variants featured a compound-[[Engineering:Delta wing|delta wing]], complete with inboard tail fins. Power was provided by an arrangement of between one and four rocket engines positioned upon the rear fuselage.<ref name = "newsci86"/> Due to the relatively low re-entry speed anticipated, it was believed that complex heat-resistant tiling could be dispensed with in favour of simpler and cheaper [[Chemistry:Nickel|nickel]]-[[Chemistry:Alloy|alloy]] panelling across the vehicle's underside. Mustard was to be crewed by between three and six [[Astronaut|astronaut]]s.<ref name = "newsci86"/>

Operationally, there were two primary vehicle configurations, the orbiter and booster stages, respectively. The orbiter vehicle, which carried the desired payload, featured ducting to receive fuel from the boosters, while the booster units incorporated systems for transferring fuel across to the orbiter vehicle or between one another.<ref name = "newsci86"/> In this fashion, the orbiter could remain fully topped-up for its long orbital injection flight, while all the vehicles could still share a standardised fuel tank design. According to Smith, the orbiting vehicle would have been capable of performing between 30 and 50 launches before needing to be replaced, while the booster engines, which wouldn't have been subject to as much heat and stress, would have remained usable for up to 200 times.<ref name = "newsci86"/>

===Clustering and stacking===
Various clustering and stacking arrangements were explored. Where the Astro would have launched as a two-stage step-rocket, for which the booster would have been much larger than the orbiter, Mustard comprised from three to five near-identically sized modules. Early studies focused on a vehicle with a shallow 120° "vee" underside to both body and wings so that three could be clustered in a triangle. Some included a fourth, orbital vehicle mounted on top of three boosters. The most efficient regime was to empty one booster at a time, keeping the others topped up for as long as possible, so that the first-stage booster could be dropped as soon as possible. The three boosters would be emptied in turn. But this led to an asymmetric mass loading which BAC believed to be a significant problem, so later designs used a sideways stacking system in which flatter modules were stacked more like sheets of paper.<ref name="sharp2016"/>

At {{convert|150,000|to|200,000|ft|m|abbr=on}}, at around 30 nautical miles, the last of the booster units would separate; once clear, these units would glide downwards and land upon a runway similar to conventional aircraft, allowing for their reuse.<ref name = "newsci86"/> The spacecraft would place its payload into orbit at around 1,000 nautical miles, which would be achieved roughly 10 minutes after launch, and then return to Earth via a controlled gliding descent before conducting a landing in a similar fashion to the booster units. Originally, it was envisioned that all three vehicles would be crewed, however, when commenting during the mid-1980s, Smith observed that, due to technological advances, it would be possible for the booster units to be entirely automated using existing technology.<ref name = "newsci86"/>

==See also==
* [[Engineering:List of canceled launch vehicle designs|List of canceled launch vehicle designs]]
*[[Engineering:HOTOL|HOTOL]]
*[[Engineering:Space Shuttle|Space Shuttle]]
*[[Engineering:Triamese|Triamese]]

==References==
===Citations===
{{reflist}}

===Bibliography===
{{refbegin}}
* Hill, C.N. "A Vertical Empire: The History of the UK Rocket and Space Programme, 1950–1971." ''World Scientific'', 2001. {{ISBN|1-78326-145-5}}.
* Sharp, Dan. ''British Secret Projects 5: Britain's Space Shuttle.'' Crécy, 2016. {{ISBN|1-9108-0902-0}}
{{refend}}

==External links==
* [https://web.archive.org/web/20141021114215/http://www.unrealaircraft.com/wings/bac_mustard.php Unreal Aircraft – Weird Wings – BAC MUSTARD]
* [https://www.flickr.com/photos/chrisstreckfus/3021701004/ MUSTARD scale model (white one in display case backside)]
* [https://www.flickr.com/photos/chrisstreckfus/3020869411/ ^ same as above ^] (See also Martin Marietta Spacemaster)
* [https://www.economist.com/news/science-and-technology/21579794-british-defence-firm-opens-its-archives-reveal-flights-fancy-never Economist, 21 June 2013, Thunderbirds are gone: A British defence firm opens its archives to reveal flights of fancy that never flew]
* [http://www.baesystems.com/en-uk/feature/1960s-lsquothunderbirdsrsquo-projects-brought-to-life MUSTARD at BAE Systems]

{{European launch systems}}

[[Category:Lifting bodies]]
[[Category:Crewed spacecraft]]
[[Category:Rocket-powered aircraft]]
[[Category:Spaceplanes]]

{{Sourceattribution|BAC Mustard}}