Tim Furniss/LONDON
Selecting a possible landing craft later this summer will be the last stage in defining the science payloads for the European Space Agency's (ESA) Mars Express mission, which ESA hopes to launch in June 2003 if it receives the go-ahead in November.
The decision to proceed with the $165 million Mars Express mission, even with additional contributions from interested member states, will require ESA's science programme office to make sacrifices. Other projects may have to be delayed or even cancelled. The go-ahead also depends on how keen member states really are on flying the mission.
The scientific instruments for the Mars Express orbiter have already been selected and ESA has invited tenders to build the spacecraft from two consortia: Alenia/Aerospatiale and Daimler-Benz Aerospace Space Systems/Matra Marconi Space (Dasa/MMS). The Dasa-MMS link has yet to be formalised.
With the launch just five years away, the programme will require fast work from ESA, which has a reputation for taking its time. The June 2003 launch window provides a good opportunity to reach Mars more quickly, because of the planet's position relative to the Earth at that time. This means that a heavier payload can be carried than would otherwise be possible.
FLEXIBLE MISSIONS
"This brisk pace," says ESA, "is also fitting for the prototype of new Flexi [flexible] missions." The Mars Express will be the first of what should become a series of relatively inexpensive and quick projects introduced into ESA's science programme, replacing the previous Medium class of planned missions in the agency's Cornerstone series. The Flexi missions are intended to keep down ESA costs and place more responsibility on the industrial contractors and scientists.
The Mars Express programme was born when the Russian Mars 96 spacecraft fell, in pieces, into the Pacific Ocean in November 1996, taking with it several European experiments. An added factor was the tantalising evidence that water once flowed over the Martian landscape, greatly improving the practical possibilities of human ventures on Mars.
A team led by the University of Rome will contribute the subsurface radar-altimeter instrument for the Mars Express orbiter, to map the distribution of possible ice and water. The link between the solar wind and the disappearance of water on Mars will be investigated by the Swedish Institute of Space Physics, and the escape of gases from Mars will be detected by an instrument provided by France's Service d'Aeronomie. Comprehensive observations of gases, dust and weather on Mars will be made by an infrared instrument provided by Italy, while another French experiment will map the planet's mineralogy. Germany will supply a stereo camera, with a resolution down to about 12m, and a radio science experiment.
DATA RELAY ROLE
The Mars Express orbiter could also act as a data relay satellite for NASA's future Mars Surveyor programme, which includes a sample return mission planned for 2006.
The UK could be the leader in providing a lander for the Mars Express, which at the moment is regarded only as an option. The UK's Open University, in conjunction with the University of Leicester and with co-operation from other European countries, is proposing a 60kg craft, called the Beagle 2, which will be dedicated to exobiology and will carry an integrated package of experiments to seek evidence of possible past life on Mars. Many scientists have made an assumption that, if there was water on Mars, there must automatically have been life.
The Beagle's instrument suite will include a drill to provide samples from beneath the surface of Mars that have not been exposed to the harsh oxidising conditions on the surface. Samples would be investigated on board the craft for the presence of organic molecules indicating life processes and other tell-tale activities of biological activity.
ESA can contemplate the Mars Express mission because, within member states, there already exists instrumentation suitable for the task which would incur virtually no development costs. The Open University, for example, has developed an evolved-gas analyser for ESA's funded Rosetta mission to land on a comet and sample its soil. This is therefore a strong contender for the key life detection experiment on any Mars lander.
The UK Government will not provide any funds for the programme, so the Open University will have to find an estimated $41 million from private sources. If the Beagle does not materialise, its 60kg will be added to the Mars Express orbiter, enabling it to fly with a heavier science payload.
Source: Flight International
