Space agency picks targets in search for past water activity on Mars, with second rover due to land on 24 January

While NASA basks in the successful landing of its first Mars expedition rover, Spirit, the European Space Agency's efforts to establish contact with the missing Beagle 2 lander have met with failure. ESA's first attempt to contact Beagle 2 from the orbiting Mars Express on 7 January failed. Further attempts were planned for subsequent passes over the landing site, but certainty is growing that the lander is lost.

NASA, meanwhile, met a hitch in the otherwise smooth start-up of the Spirit when it was determined that two sections of the airbags that cushioned its 3 January touchdown partially blocked the ramp the rover was to use to leave its lander. This delayed plans to roll the six-wheeled rover off the lander by three days, to 14 January at the earliest.

Engineers planned to lift a lander petal then further retract the now-deflated airbags under the platform. If this "lift and tuck" operation, planned for 8 January, was unsuccessful, the robotic rover will have to pirouette round on the lander platform to use one of the other two ramps. An intermittent current spike in one of two motors driving the rover's high-gain antenna has been resolved.

While Spirit remained on its lander, NASA began using its high-resolution panoramic camera (Pancam) and miniature thermal emission spectrometer (Mini-TES) to pick likely targets for its search for signs of past water activity on Mars. Colour stereo images from the mast-mounted Pancam have a resolution three times that of pictures returned by the Mars Pathfinder rover in 1997.

The first images have both excited and puzzled mission specialists. Spirit's landing site in the Gusev Crater was selected because scientists believe it could once have contained a lake, but instead of the relatively smooth and wind-blown dry lakebed they expected,the view is surprisingly undulating and rock-strewn. Lakebed deposits may still be present, but more difficult to find, says NASA.

The second of the twin Mars expedition rovers in the $820million mission, Opportunity, is due to land on 24 January. It is targeted at Meridiani Planum, on the opposite side of Mars, a region containing exposed deposits of hematite, a material that usually forms under watery conditions. NASA's Mars Global Surveyor (MGS) orbiter is profiling the atmosphere over the landing zone in the wake of a dust storm in the region.

The twin rovers are designed to trek up to 100m across the planet's surface each Martian day. The sun will only provide enough solar power for driving during a 4h window around noon, NASA says.

The 185kg rover will navigate from target to target using the mast-mounted Pancam, a stereo pair of navigation cameras, inertial measurement unit and two sets of stereo hazard identification cameras. The six wheels, with individual motors and suspension systems, will let the rover make a 360¡ turn in place and tilt up to 45¡ in any direction without overturning.

Close-up inspections of surface samples will be performed using a robot arm carrying a microscopic imager, magnets for collecting dust particles, two spectrometers and a rock abrasion tool capable of creating a 45mm (1.8in)-diameter, 5mm-deep hole in a rock to provide samples. Each rover is expected to complete 90 days of operations before power levels fall as dust accumulates on the solar panels, the batteries lose capacity and the sun moves north.

ESA hoped to establish communications with the Beagle 2 during Mars Express orbits on 8, 9, 10, 12 and 14 January. Other attempts will be made by radio telescope on 2 February, when the 34kg lander is to switch to a back-up communications mode. ESA cites three possibilities for Beagle's silence: a software glitch; a receiver or transmitter problem; or the probe was destroyed on landing on 25 December.

Source: Flight International