NASA has confirmed that it will launch two identical Athena rovers to Mars in 2003, increasing the cost of the mission but also its chances of success. The move follows the embarrassing loss of the Mars Polar Lander last year.

The second Mars rover will add up to $200 million to the $350-400 million cost of the mission. NASA says its space science budget will cover any extra costs for the first rover mission, while the bulk of the cost for the second lander will be reallocated from programmes outside space science.

The decision to send two rovers is likely to stretch a budget already straining to cover mission costs which are being forced upward in response to criticisms of NASA's "faster, better, cheaper" approach after the Mars mission failures.

Mars programme director Scott Hubbard says an extensive study of the two-lander option, weighing the potential scientific return against the resource requirements and schedule constraints, concluded the approach "adds resiliency and robustness".

Both rovers will be launched by Delta II, the first on 22 May 2003 and the second on 4 June. They are due to enter Mars' atmosphere within days of each other in January 2004. The landing will involve the parachute and airbag combination used successfully for the 1997 Mars Pathfinder mission, and not the retrorocket system believed to have failed in the Mars Polar Lander mission.

The 150kg (300lb) rovers will land in different locations and search for evidence of water with identical payloads, comprising a panoramic camera and a microscopic imager, spectrometers and rock abrasion tool on a robotic arm. Each rover will be able to travel up to 100m (330ft) each Martian day for at least 90 days. The landing locations will be selected from images obtained from the Mars Global Surveyor and the 2001 Mars Orbiter.

NASA hopes that the development of the Jet Propulsion Laboratory-Caltech Athena rovers will mark a new start to its Mars exploration efforts.

Source: Flight International