A radar boom on the European Space Agency's Mars Express spacecraft did not completely straighten out after it deployed, the agency says.
Mission members say the problem will probably have little effect on the boom's ability to search for underground water on Mars, but they have delayed the deployment of a second boom - crucial for the experiment to function - to investigate the matter.
On 4 May, mission officials in Darmstadt, Germany, commanded the first of two 20-metre-long antennae on the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) experiment to pop out of its storage box. It had been folded there since before the mission's launch in June 2003.
Initial telemetry for the spacecraft's movement suggested the boom had deployed successfully. But engineers combing more carefully through the data noticed on 7 May that one of the boom's 13 folded segments had apparently not locked into a horizontal position as planned. The problem appears to be with the 10th segment.
"Apparently it can still take data, but it is much too early to say so with certainty," ESA spokesperson Jocelyne Landeau-Constantin told New Scientist. "We want to understand why it happened, how it can be remedied, and whether the second antenna can be deployed."
Another mission member confirms the glitch is not likely to affect the boom's ability to take data but says there is probably nothing that could be done to straighten the segment out.
MARSIS - which includes a second 20-metre "dipole" and a 7-metre "monopole" - will not be able to function until the other dipole boom is deployed. That event had been planned for 8 May, but has now been postponed indefinitely.
It will not be the first delay for the radar, which was originally set to be deployed in April 2004. But ESA postponed the date over concerns the antenna could endanger the mission by smacking into, or getting snagged on, the spacecraft during deployment. The agency later decided to proceed with the deployment when further Earth-based reconstructions showed the antenna material had only a small chance of damaging the craft in the event of a strike.
MARSIS works by sending out pulses of radio waves from the two longer booms and analysing the time delay and strength of the waves that return. Most will rebound from the surface, but some of the longer wavelength waves may penetrate the porous rocky soil. These would bounce back when they encounter a transition between two materials with different electrical properties - such as between rock and liquid water.
Scientists hope to discover whether the water that once carved canyons on the Red Planet's surface has seeped into underground reserves. If there are underground caches, they may harbour life, or could perhaps be used to supply future crewed missions to Mars.
All comments should respect the New Scientist House Rules. If you think a particular comment breaks these rules then please use the "Report" link in that comment to report it to us.
If you are having a technical problem posting a comment, please contact technical support.
