Sidebar: The Multi-Role Capsule

multi-role-capsule

The only contemporary image of British Aerospace’s Multi-Role Capsule—a competitor to the ESA’s Hermes spaceplane—of which the author is aware. The capsule itself is the larger aft section to the right, while the service module is in the foreground left. Originally published in Flight International magazine, October 24, 1987. Click for a larger view.

When the ESA settled on the Hermes spaceplane in November 1987 there was one dissenter from the ambitious space program of which it was part. The British government of Margaret Thatcher was in the process of killing the British spaceplane HOTOL due to its technical difficulties and weren’t keen on supporting another one. As a result one of HOTOL’s designers, British Aerospace, was about to be left out of the European initiative. Without much support from anyone they suggested just prior to the formal adoption of Hermes that Europe might want to talk a look at an expendable capsule for trips to and from the US’ as-yet-unnamed Freedom space station. They also put it forward to NASA as a possible lifeboat if astronauts ever had to leave Freedom in a hurry.

BAe knew that Hermes was the favorite, and so positioned what they called the Multi-Role Capsule (MRC) and being cheaper and quicker to build. It would also have been capable of being lifted by a modified Ariane 4, rather than the new specifically-designed-for-Hermes Ariane 5 on which the ESA was spending so much of its budget.

The spacecraft consisted of two modules, a crew cabin called the Descent Module (DM) and an ejectable Service Module (SM) for any systems that weren’t needed for re-entry and the DM’s splash-landing on Earth. This is the arrangement of many capsule-based designs, built or merely proposed, but the MRC was unusual in that the SM was considerably smaller than the capsule (796 kilograms, versus an unfuelled mass of 6204kg for the latter) and mounted on the nose of the DM instead of its tail. The SM’s low mass did mean that the MRC would not have had much maneuvering capability while in orbit.

After launch the capsule would have held four to six astronauts, or none at all if the mission didn’t need a human touch. One of the latter type would have been docking with the upcoming US Space Station Freedom for use as an escape capsule if the station had to be evacuated. BAe specifically positioned this as the MRC’s first role, hoping that a go-ahead from NASA would overcome Hermes’ momentum, or at least get the MRC developed in conjunction with the spaceplane. British Aerospace sweetened the pot further by making the DM reusable (the SM was to have been expendable) and proposing to build a full MRC for a relatively inexpensive US$183 million—after adjustments for inflation, comparable to an Apollo CSM.

Unfortunately for British Aerospace they couldn’t get the ESA to back their idea, and their fallback of building them for the US didn’t work either. NASA did study return capsules for Freedom and Alpha, but did so in house: as might have been suspected up front, they already had extensive experience building their own space capsules and didn’t see any good reason to have them designed and built out of the country. Even at that, NASA ended up deciding against capsules for rescue missions anyway because they felt that the high g-loads of a capsule re-entry would be a problem in the case of a medical emergency (though in the end not even the Americans ended up building the mini-spaceplane that would be necessary to get around that problem).

It’s also telling of British isolation from the ESA’s mainstream at the time that, after the Multi-Role Capsule had faded away, a coalition of the aerospace contractors Aérospatiale, Deutsche Aerospace, and Alenia Spazio (respectively representing France, Germany, and Italy) went ahead with an independent study of a capsule-based escape craft for the ISS, thus essentially duplicating what the British Multi-Role Capsule was to have done as its first job. The ACRV, as it was called, was also cancelled.

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2 thoughts on “Sidebar: The Multi-Role Capsule

    • That’s an interesting find, Dwight! You have to wonder if the Star Trek model designers managed to rediscover the design….

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