Designers built the 2,000-pound craft with lessons from Spirit and Opportunity in mind , including a longer , more advanced robot arm , a hammer drill that can crack apart rocks and a laser that reduces rock to a hot plasma , allowing an on-board spectrograph to determine its composition . The Mars rover Opportunity has survived eight and a half years on Mars . The 5-foot craft was designed to last 90 days . Hide Caption ` We 've taken great care '' in operating it , former driver says .
The Mars rover Opportunity has survived eight and a half years on Mars . The 5-foot craft was designed to last 90 days . Hide Caption ` We 've taken great care '' in operating it , former driver says .