The first task of Phoenix's newly deployed robotic arm will be to check out the lander's underbelly and the terrain beneath it. After a health check to test how well it operates at a range of temperatures, Phoenix will use a camera on the eight-foot arm to peer at the lander's underside so that mission control can confirm it is stable and won't topple over when the arm is fully extended.
Yesterday Nasa reported that the titanium and aluminium arm had been freed from the restraints that kept it stowed and protected from vibrations during launch and landing. Commands were sent to Phoenix to rotate the arm's wrist to unlatch its launch lock, raise the forearm and move it upright to release the elbow restraint.
The arm will eventually be used to excavate the icy terrain and deliver samples to instruments that will determine what the northern plains of the Red Planet are made of, whether the water there was ever liquid, and whether it has ever harboured microbial life.
As well as freeing its arm yesterday, Phoenix transmitted a 360-degree panorama of its frigid surroundings and lifted the lid on a laser instrument called a lidar (Light Detection And Ranging instrument). The lidar beam will bounce light off dust in the atmosphere to a height of 2 miles.
Nasa reported that the weather at the Phoenix landing site on the second day following landing was "sunny with dust activity", with temperatures reaching a high of -30C and a low of -80C.
Perhaps in the hope of making them sound more interesting to the general public, the agency has given fanciful names to the various indentations and rocks in the lander's vicinity, including Humpty Dumpty, the King's Horses and King's Men, and Sleepy Hollow. A virtual line has been drawn in the dirt, with the area to the right designated the National Park, which will be kept pristine until the lander has finished testing its robotic arm and scoop in the less interesting area to the left of the line. This will no doubt become known as the Sand Pit.
