digging in a larger tunnel phoenix ' s robotic arm deals with a soft surface that has been excited about the potential of next uncovering an icy trench . " we have dug a trench and uncovered a soft layer at the same location as the ice thickness in our other sector , " said washington university robotic team investigator for phoenix , rays arvidson . the team tried at most three times to pierce the pile , but was unsuccessful . as a consequence the body went into a holding pattern , delaying its next task .
a human arm has been used for astronomical discoveries .