Hawker Siddeley's last attempt to arouse official interest in Blue Streak came in 1972 with a brochure proposing to use the American Centaur upper stage on Blue Streak.
The brochure is not very impressive - it looks a rather hasty affair, with text in block capitals throughout, and is rather short on detail. There are no costings.
The Kourou launch site is suggested, but there may well have been political problems. Although it had Blue Streak launch site (used once for F11), the vehicle would have been an obvious competitor for any future Europa III. And the French would not have been keen on a launcher using an American stage.
This is the design:
The French L17 strap on stages had been suggested earlier for the ELDO launcher.
Payload to geosynchronous orbit was given as 650-700kg with no boosters, 870-920 with 2 L17s, 1000-1050kg with 4 boosters grouped in 2 pairs.
It was suggested that the Centaurs could either be purchased direct or built under licence.
As a design, it had a lot to commend it. Both stages were fairly reliable by this stage. Development costs should have been quite low, and the payload quite respectable.
However, the British Government by this stage had its face firmly set against any participation in launchers by this stage - an attitude still as firmly maintained more than thirty years later.
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