Europe and Japan agree to collaborate on Mars missions
16 July 1999The European Space Agency and the Japanese Institute of Space and Astronautical Science (ISAS) have agreed to open up their Mars missions to each other's scientists. European principal investigators on ESA's Mars Express mission are due to travel to Japan later this year to learn about the science on ISAS' Nozomi mission. Their Japanese equivalents will visit Europe to learn about Mars Express next year. "We are setting up a joint programme of Mars exploration between ESA and ISAS which links the two agencies as equal partners," says Agustin Chicarro, project scientist for Mars Express at ESTEC, ESA's technical centre in The Netherlands.
The collaboration is the happy outcome of an unfortunate incident. Nozomi was launched in July 1998 for arrival at Mars in October 1999; but just a few weeks after launch the failure of valves on its propulsion line left it with insufficient fuel to complete its planned journey. Nozomi will now wait in a parking orbit until it can take advantage of an economy passage to Mars assisted by the gravity of two Earth swing-bys in December 2002 and June 2003. It will arrive at the red planet just after Mars Express. "Both spacecraft will now arrive at Mars within a week of each other. Mars Express will go into a polar orbit and Nozomi will orbit the equator. The two missions are absolutely complementary in terms of science," says Chicarro. The two orbits, almost perpendicular to each other, will give complementary views of the planet - and the scientific instruments each spacecraft is carrying will also allow both co-ordinated and complementary observations. Nozomi has 14 instruments which will concentrate mainly on investigating the interaction of the solar wind with the upper atmosphere. It also carries a magnetometer for investigating the vestiges of the Martian magnetic field and a dust counter for studying dust in the atmosphere near Phobos and Deimos, the two Martian moons.
Mars Express's seven instruments and lander will image the planet at high resolution, study its geochemistry and look for water and life. The main area of overlap between the two missions is in studies of the ionosphere and upper atmosphere. "We will be able to coordinate measurements. Some imaging could be done simultaneously of certain phenomena," says Chicarro.
Information sharing between the Mars Express and Nozomi instrument teams has already begun.