Palapa satellite rescued

Chris Forrester

On August 31 the Chinese launched an Indonesian satellite, Palapa-D, aboard a Chang Zheng-3B ‘Long March’ rocket, from the Sichuan launch site in South-West China. But the third stake of the rocket failed to function correctly, and the satellite was left in a highly elliptical orbit. The initial news was all bad, but a clever rethink by engineers at Thales Alenia Space have saved a messy – and potentially expensive – situation.

Thales, which manufactured the satellite, managed to capture the craft and propel it towards its correct orbit, and en-route to its designated position at 113 degrees East.

The craft was ordered back in July 2007, and is larger than the satellite it is to replace. Palapa-D has 35 C-band transponders plus 5 in Ku-band.

The Chinese used their most powerful rocket in what was supposed to be a showcase of their launch skills. There was, says Reuters, a news blackout for some hours following the failure. The rocket’s 3rd stage failed about 20 minutes into the flight, leaving the satellite circling the Earth in a useless orbit of just 130 miles at its lowest point, and 13,150 miles at its highest.

While news out of China is a little sketchy at the moment, the normal pattern for such rescue missions is for the technicians to use some of the satellite’s own precious on-board fuel to ‘kick start’ it out of the elliptical orbit and using this fuel to propel the rocket to its designated position. However, the downside is that the satellite is then left with much less fuel than designed, and certainly not enough for a 15-year planned life.