Search for Two Mars Landers to Continue

As our closest neighbor in the solar system, Mars is the planet which has been most closely studied. Over the years a number of spacecraft and landing craft have been sent to the planet and these have met with varying degrees of success. In 1999 the Mars Polar Lander was launched and after an 11 month journey reached the planet. However as it was attempting to land all contact was lost and this proved to be an unsuccessful mission. In 2008 the Mars Phoenix Lander arrived safely on the planet and went on to complete its mission before contact was lost as a result of the harsh Martian Winter. Although it is considered unlikely that contact will be re-established with either of these craft, all hope has not been given up that signs of life could be detected and the search for both will continue in early 2010.

The Mars Polar Lander mission was launched in early 1999 and following an 11 month cruise the spacecraft arrived at Mars in December 1999. The mission had been designed to study the weather, climate, water and carbon dioxide concentrations on Mars and a number of scientific instruments had been incorporated into the Polar Lander to undertake studies when it arrived. However the last contact with the craft came just prior to atmospheric entry and no further contact has ever been established. The exact cause of the communication loss is not known although an investigation identified the most likely cause as being a software error that misread vibrations caused by deployment of the crafts legs as touchdown on the surface. This would have caused the descent engines to switch off while the craft was still above the surface of the planet resulting in an extremely hard landing. In late1999 and early 2000 images from the Mars Global Surveyor were used to search for the Polar Lander although this was unsuccessful and contact with the craft was never established.

The search for the Mars Polar Lander has not been given up entirely however and in the last two years images from the HiRISE camera on the Mars Reconnaissance Orbiter have been used to try and identify the site of the craft. This began in 2008 when 18 images were released to the public with a request that anyone who wanted to assist the search could view the images and contact the HiRISE team with any points of interest. This was not successful although as new images have been released the search has continued. Some of the existing images have been improved by the HiRISE team and these were released in December 2009. Whether these will finally reveal the site of the Mars Polar Lander remains to be seen but the search will continue in 2010.

The Mars Phoenix Lander was the first mission to Mars following the failure of the Mars Polar Lander. The aim of the mission was to study the history of water on the planet and to search for environments suitable for life to have existed. The craft was launched in August 2007 and arrived at the planet in May 2008. It successfully negotiated the descent to the planet and over the next few months carried out its mission and transmitted the data back to Earth. However the craft was not designed to cope with the Martian winter and as this closed in contact was lost.
During winter the Phoenix Lander should have gone into safe mode and if it survived the harsh conditions it should try to recharge its batteries as the weather improves. On January 18 the Mars Odyssey Orbiter will begin a mission to start listening for any signs of life from the Phoenix Lander. Odyssey will pass over the location of the craft 10 times a day over a 3 day period in January and will follow this up with two longer search periods in February and March. During the two longer periods it will passively listen as well as transmitting signals which the Phoenix Lander will potentially be able to hear.

If the Phoenix Lander has survived the Martian winter it should start to periodically attempt to communicate once the solar panels have generated enough electricity. If it does this then Odyssey should be able to hear these and would try to re-establish contact. The initial task would then be to try and determine the condition of the Phoenix Lander and the capabilities it retains. This information could then be used to determine whether the craft has any remaining useful life.

Only time will tell whether the attempts to locate and communicate with both the Mars Polar Lander and the Mars Phoenix Lander are successful. It would be a tremendous achievement to re-establish contact and use one or both of the craft for further studies of Mars. This may be an unlikely scenario although it is not impossible and the next few months will be an interesting time in the study of Mars.