Tim Furniss/LONDON
JAPAN'S HYFLEX hypersonic flight-experiment space-plane sank in the Pacific Ocean 20min after the successful maiden flight of the J1 booster on 12 February.
The 1,040kg Hyflex splashed down 1,300km (700nm) down-range from the Tanegashima launch centre, but sank after a cable linking the craft to its flotation buoys broke.
Although data was transmitted from the Hyflex, during its re-entry from 110km altitude (reached at T+3min 40s), engineers will be unable to assess the performance of the craft's heat shield tiles, during the estimated Mach 14.4 re-entry into the atmosphere, nor know the maximum temperature experienced by the heat shield.
The Japanese National Space Development Agency had planned to use Hyflex data in the design of the unmanned HOPE space shuttle, a full-scale prototype of which is scheduled to have a sub-orbital test flight in 2000.
Automatic approach and landing experiment tests using a scale-model prototype of the HOPE are scheduled to begin at Woomera, South Australia, in about two months' time.
The Hyflex incident overshadowed the success of the two-stage, sub-orbital J1 test flight. Three-stage versions of the J1 will be capable of carrying 870kg payloads into 250km, 30¡-inclination, circular orbits.
The new booster is only scheduled for one firm flight, however, in 1998, to orbit the Optical Inter-Orbit Communications Engineering Test Satellite. Because it is under pressure from budget constraints, the J1 may have a very short career.
Source: Flight International
