Scientists and engineers from several countries outside Europe are participating in, or contributing to, Mars Express.
Of these, Russia, Japan and the United States have the greatest involvement.
Five of the instruments on Mars Express (HRSC, OMEGA, PFS, ASPERA and SPICAM) are descendants of instruments originally built for the Russian Mars '96 mission. Each of the seven orbiter instrument teams on Mars Express has Russian co-investigators who contribute their intellectual expertise to the project.
The Japanese spacecraft Nozomi, was due to go into near equatorial orbit around Mars shortly after Mars Express enters polar orbit. Nozomi had been due to reach the Red Planet in October 1999, but was delayed by a problem with the propulsion system.
Both missions shared a common interest in the Martian atmosphere. Nozomi was carrying a close relative of ASPERA, the instrument on Mars Express studying interactions between the upper atmosphere and the solar wind.
However, Nozomi had to give up its injection into orbit around Mars due to unrecoverable malfunction. The ground control team sent a command to change the trajectory to avoid colliding with Mars and to continue travelling in an orbit around the Sun.
ESA and NASA have made arrangements to use each other's orbiters as back-up for each other in relaying data and other communications from the landers to Earth.
Mars Express is also intending to use NASA's Deep Space Network for communications with Earth during parts of the mission. US scientists are playing a major role in one of Mars Express's payload instruments, MARSIS, and participate as co-investigators in most other instruments.
A global effort to explore the Red Planet
Mars Express marks the beginning of a major European involvement in an international programme to explore Mars over the next two decades. Europe, the US and Japan are planning to send missions, but many more countries will be contributing experiments, hardware and expertise.
Each mission will make its own unique contribution towards a global effort coordinated by the International Mars Exploration Working Group.
The idea for a European mission to Mars is not new. Before choosing Mars Express, ESA had debated other mission ideas including Intermarsnet, an orbiter and four landers to perform atmospheric, surface science and seismic studies from a network of widely-spaced locations on Mars.
Intermarsnet was not selected on cost grounds, but the idea and preliminary studies are not going to waste. The French space agency, CNES is planning to send four similar, though smaller and cheaper, Netlanders to Mars in 2007.
The table below summarises plans up to 2007, with plans up to 2003 being firm and those in 2005 and 2007 still subject to alteration.
|1996||Mars Pathfinder, NASA||Lander||Surface imaging and chemical composition with European instruments|
|1996||Mars Global Surveyor, NASA||Orbiter||Imaging, topography, magnetic field and surface composition|
|1998||Nozomi, ISAS *||Orbiter||Atmosphere and its interaction with the solar wind. Coordination with Mars Express.|
|2001||Mars Odyssey, NASA||Orbiter||Surface composition|
|2003||Mars Express, ESA||Orbiter||Surface, subsurface and atmosphere of Mars, in particular search for water.|
|2003||Beagle 2, ESA||Lander||Exobiology, geochemistry and surface-atmosphere interactions.|
|2003||Mars Exploration Rovers, NASA||Two rovers||Robotic explorer able to track 100 metres a day. Geology and search for water.|
|2005||Mars Reconnaissance Orbiter, NASA||Orbiter||Atmosphere and detailed imaging to identify potential landing sites.|
|2007||Orbiter plus four Netlanders, CNES **||Orbiter||Remote sensing experiments plus telecommunications between the Netlanders and Earth.|
|Landers||Atmosphere, internal structure and geology of landing sites.|
|*||ISAS =||Institute of Space and Astronautical Science, Japan|
|**||CNES =||Centre National des Etudes Spatiales, France|