Tim Furniss/LONDON

The $360 million Japanese Communications and Broadcasting Engineering Test Satellite, Comets, was stranded in low Earth orbit on 21 February when the LE-5 second stage engine of its H-2 launch vehicle shut down prematurely.

The second stage was 44s into a planned 192s burn to place the craft into a planned 35,688 x 248km transfer orbit when it shut down. The LE-5's successful first burn had earlier reached circular low Earth orbit.

The 2,200kg satellite ended up in a 1,884 x 248km, 30í inclination orbit. It was to have been placed eventually into a 36,000km circular geostationary orbit with a final burn of the craft's own motor. The failure was the first of the H-2, flying its sixth mission since 1994.

Using the Comets' kick motor, some of the craft's planned Ka-band advanced mobile, in-orbit, and multi-frequency communications tests may be able to be carried out in a raised elliptical orbit up to a maximum of 25,000km.

The failure is another setback to the Japanese space programme, following the loss of the Advanced Earth Observation Satellite in June 1997, which caused a delay of six months to the Comets launch, and problems with the development of uprated LE-7 and LE-5 engines for the planned H2 Alpha Plus vehicle, formerly known as the H2A.

Plans to launch the H2 Alpha Plus in 2000 may be thwarted by the engine test problems, which include the explosion of the LE-5B engine during a test last December. The LE-5B is to make its debut on a standard H2 in August 1999 to launch Japan's MT-SAT, being built by Space Systems/Loral.

Source: Flight International