Tim Furniss/LONDON

Japan launched its first Mars probe on 4 July. The Institute of Space and Astronautical Sciences' (ISAS) $80 million Planet B spacecraft, renamed Nozomi, was launched into a highly elliptical Earth orbit on the second flight of the agency's 31m-high, M-5 solid propellant booster, from Kagoshima.

At the same time as the Japanese started their journey to the Red Planet, their counterparts at NASA were being forced to reduce the scope of the USA's next Mars mission for budgetary reasons.

The 540kg Nozomi will make two "swing-bys" of the moon in September and December before firing its motor to despatch it on a 700 million kilometre journey to Mars, which it will reach in October 1999.

The spacecraft will go into orbit around Mars at an altitude of about 135km, making a series of scientific observations using 14 instruments, including equipment contributed by Canada, Germany, Sweden and the USA.

Nozomi will study how the solar wind affects the largely carbon dioxide Martian atmosphere by stripping it of its rare oxygen. It will also photograph the planet's surface, particularly during Martian dust storms.

After a series of Japanese failures, ISAS has admitted it is under heavy pressure to succeed and another setback with Nozomi could result in future programmes being cancelled.

Two more ISAS flights are budgeted - the Lunar A in 1999 and the highly ambitious Muses C flight in 2002, which will attempt to bring back a sample from an asteroid.

Meanwhile in Washington, NASA, faced with budget difficulties, has removed the Athena Mars Rover from the Mars Surveyor Lander 2001 mission.

A much smaller rover, based on the successful Mars Pathfinder Sojourner rover, may fly in its place. The Mars Pathfinder landed on 4 July last year.

Athena was to have conducted the most detailed in situ analysis of Mars rocks yet attempted and would have collected some samples that would have been left on the surface for a planned 2005 Mars sample return mission.

The cost and weight of the rover exceeded expectations. The estimated expense of the Mars Surveyor 2011 mission had increased from $267 million to almost $400 million.

NASA plans to fly the Athena rover on a Mars Surveyor Lander 2003 mission and the organisation intends to launch the sample return flight two years later.

Exactly how the sample return mission will be attempted has yet to be decided, and this is causing uncertainty about the technical and missions direction that precursor flights should take.

Source: Flight International