A pioneering demonstration of communications between
NASA’s Mars Exploration Rover Spirit and the European Space
Agency (ESA) Mars Express orbiter succeeded.

On February 6, while Mars Express was flying over the area
Spirit was examining, the orbiter transferred commands from
Earth to the rover and relayed data from the robotic explorer
back to Earth.

“This is the first time we have had an in-orbit communication
between ESA and NASA spacecraft, and also the first working
international communications network around another planet,”
said Rudolf Schmidt, ESA’s project manager for Mars Express.
“Both are significant achievements, two more ‘firsts’ for Mars
Express and the Mars Exploration Rovers.”

Jennifer Trosper, Spirit mission manager at NASA’s Jet
Propulsion Laboratory (JPL), Pasadena, Calif., said, “We have
an international interplanetary communications network
established at Mars.”

ESA and NASA planned this demonstration as part of continuing
efforts to cooperate in space and to enable plans to use joint
communications assets to support future missions to the surface
of Mars.

The commands for the rover were transferred from Spirit’s
operations team at JPL to ESA’s European Space Operations
Centre in Darmstadt, Germany, where they were translated into
commands for Mars Express.

The translated commands were transmitted to Mars Express, which
used them to successfully command Spirit. Spirit used its
ultra-high frequency antenna to transmit telemetry information
to Mars Express. The orbiter relayed the data back to JPL, via
the European Space Operations Centre.

“This is excellent news,” said JPL’s Richard Horttor, project
manager for NASA’s role in Mars Express. “The communication
sessions between Mars Express and Spirit were pristine. Not a
single bit of data was missing or added, and there were no

This exercise demonstrated the increased flexibility and
capabilities of interagency cooperation and highlighted the
spirit of close support essential in undertaking international
space exploration.

Spirit and its twin Mars Exploration Rover, Opportunity,
frequently use two NASA orbiters, Mars Odyssey and Mars Global
Surveyor, for relaying communications. The rovers also can
communicate directly with the Earth-based antennas of NASA’s
Deep Space Network in California, Spain and Australia, another
layer of international cooperation.

JPL, a division of the California Institute of Technology in
Pasadena, manages the Mars Exploration Rover Project and NASA
participation in Mars Express for NASA’s Office of Space
Science, Washington.

For information about NASA and Mars programs on the Internet,


For images and information about the Mars Exploration Rover
project on the Internet, visit:



For images and information about Mars Express on the Internet,