pbd points out a story discussing the challenges faced by NASA engineers in designing the code sent to operate the Phoenix Mars Lander
. Quoting Computerworld:
"On Wednesday, engineers sent up the code to run an actual analysis, but a satellite orbiting Mars, which transfers the data down to the Lander, was offline. Robinson explained that the satellite had been hit with radiation, knocking it into safe mode. 'Space is a harsh environment, and sometimes they just go into safe mode,' he noted. 'It's a minor problem. [The satellite] aborts whatever it was doing and waits for future commanding.' Engineers successfully resent the code on Thursday."