They were supposed to survive only 90 days. Yet they’ve lasted for two years – two Earth years, that is.
But one of the men who controls Spirit and Opportunity, two NASA rovers exploring Mars, said he isn’t surprised.
“They are very well-built machines. I wouldn’t be surprised if they lasted another year,” said Ray Arvidson, the deputy principal investigator for the mission and a faculty member in Washington University’s Department of Earth and Planetary Sciences.
The department’s building is one of 30 sites around the nation that manage the rover. Arvidson, along with other faculty, undergraduates and graduate students, holds a series of meetings each day with the other sites to coordinate rover activities.
The two rovers landed in Jan. 2004 on opposite sides of Mars, near the equator. The mission’s purpose was to see if the planet had water in the past. Liquid water does not exist today on Mars due to its extremely cold climate, but there is direct evidence that liquid water once flowed on the planet.
Right now, Spirit is climbing Husband Hill, looking for exposed rocks on the crust of the planet like sandstone, ejecta, and ash, and it has found that all of them have been modified by groundwater trickling through those areas.
The Opportunity rover is examining a set of rocks very close to the surface that formed in shallow lakes billions of years ago.
The average day for Arvidson and his team starts around 10 a.m., when there is a kick-off meeting in which about 30-40 people discuss what they would like the rovers to do. The ideas are then narrowed down to the most important activities and compiled in a computer list.
Two or three hours later, there are two successive walkthroughs where the group discusses preliminary summaries and reviews of sequences. Finally, around 6 p.m., there is a Commander Approval Meeting (CAM) where the group makes sure that the processes are safe and scientifically important. The data is then given to the NASA engineers who form the data into a radio signal to be sent to the rovers.
The machines are solar-powered and must receive their instructions during the Martian day, meaning making contact with them can be a harrowing task.
“Every day, Earth time moves 39 minutes ahead of Mars time. Also, the two rovers are on opposite sides of the planet. We have to keep three times in mind and we really have to watch the times,” said Arvidson.
NASA and the University are planning future Mars missions, which they hope will uncover more secrets of the planet or perhaps even life.
“These zones are places that had the right stuff at the right time to form life,” said Arvidson.
In the meantime, he is basking in the success of the current rovers.
“NASA is very proud of the mission,” he said.