A propellant shortage will force a delay in Japan's $80 million Nozomi Mars probe reaching its target until towards the end of 2003, four years late.
Launched last July, the Nozomi used more propellant than planned during a burn on 21 December to correct a deviation during a gravity-assist fly-by of the earth to place it on its original course for Mars. The deviation was caused when the probe ran into difficulty after an engine valve malfunctioned during a complementary burn.
The Nozomi would not have enough fuel to make its orbital insertion burn if this was attempted in October 1999. By waiting until December 2003, engineers can take advantage of Mars' orbital position around the sun, in which its relative speed will be slower.
This targeting will be achieved by making another gravity-assist fly-by of the earth in June 2003. From its 153 x 43,000km elliptical orbit around Mars, the Nozomi will eventually return images and atmospheric data and will be operating in tandem with Europe's Mars Express orbiter.
Source: Flight International
