NASA鈥檚 Opportunity rover has once again freed itself from a sand trap on Mars.
On 28 May, the rover鈥檚 two rear wheels became mired in loose soil that the vehicle unexpectedly encountered while driving in a trough between two dunes. The rover was expected to drive for 24 metres but only made it 1.5 m, as its wheels churned in the soft soil.
To escape, the rover drove backwards for 5 to 28 centimetres each day. And at 0600 EDT (1000 GMT) on Tuesday, mission managers learned that the strategy had worked 鈥� all six of the rovers鈥� wheels were back on solid bedrock.
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Rover officials do not yet know what caused the wheels to get stuck, but they planned to turn Opportunity鈥檚 cameras back on the trouble spot on Tuesday to find out more.
And they have decided to name the sand trap 鈥淛ammerbugt鈥�, which translates to 鈥淏ay of Lamentation鈥� in Danish. 鈥淚t鈥檚 a bay on the northwest coast of Denmark that historically has been the site of many shipwrecks,鈥� Steve Squyres, the rovers鈥� principal investigator and a planetary scientist at Cornell University in New York, US, told New 杏吧原创.
Slip checks
The rover team will continue to use Danish names for any new features it discovers in the next several weeks, in honour of the country鈥檚 contributions to the mission. Several Danes work on the rover and Danish institutions provided instruments to study magnetic minerals in the Red Planet鈥檚 soil, rocks and atmospheric dust. Denmark also celebrated its Constitution Day on Monday.
This is not the first time Opportunity has become trapped on Mars. It got stuck in another location, nicknamed 鈥淧urgatory Dune鈥�, in April 2005, and was delayed for five weeks.
That experience caused the rover team to implement slip checks that stop the rover from driving if its wheels slip beyond a certain amount. The checks prevented Opportunity from getting seriously entrenched in this trap.
After the rover observes the soil that ensnared it, it will continue trundling south towards an 800-metre-wide crater called Victoria that still lies 900 metres away. 鈥淪outhward ho,鈥� Squyres says.
