Slide 82 of 99
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Ariane-5/Hermés launch. Both projects were approved as new ESA projects in November 1987. The total cost in 1988-2000 was expected to be $3.36 billion for Ariane-5 with a first launch in 1995 and two further qualification flights. Hermes would cost $4.25 billion, including two qualification flights on the Ariane-4 starting in mid-1998. However, the Space Shuttle Challenger disaster in 1986 also greatly affected the Hermés/Ariane-5 design. The crew size was reduced 50% to three astronauts since the cabin has to be ejectable. The payload mass had to be reduced from 4550kg to 3000kg inside a pressurized cargo compartment. The launch weight of the spaceplane was now 21t and the Ariane-5 had to be uprated to launch it. The rocket's solid boosters would now contain 230t of propellant instead of 190t, and the central core would contain 155t of liquid rocket propellant instead of the original 140t.
The Hermés spaceplane returns to Earth in this illustration from the late 1980s. The program's $530-million “Phase 1” detailed definition lasted from March 1988 to February 1990. Crew safety and unplanned weight growth were major problems. The designers initially considered a Crew Escape Module that would have cost 400 million ESA Accounting Units (MAU), then looked at smaller 50-MAU encapsulated ejection seats derived from German “Mikroba” capsules. ESA finally settled for ordinary ejection seats instead of an ejectable cabin, although they would not be able to save a crew above 22-29km altitude.
