Few rovers have had the opportunity of prancing about the Martian surface. Well, three, actually. For one of them, a nice moment will be arriving soon. The 7th winter is coming for Opportunity Rover on Mars, and, along with it, the anniversary of a staggering 11 years on the Red Planet.
Opportunity’s life has been a long and busy one. However not interesting for the little rover – mainly just looking at dust, and rocks, and some more dust and rocks – it’s been a pleasure for the scientists working with the machine.
Not only did it land far back, in the last decade, in very distant 2004. It was made to work for three months. 11 years in, and it’s still going! By comparison, Spirit, its twin brother, which also landed in 2004, turned out to be stuck at the end of 2009. It eventually made its last communication on March 22nd, the next year.
Recently, Opportunity had to deal with three weeks of reduced activity due to the positioning of the sun between the Mars and the Earth, which prevented communication between the rover and the control room.
Since the mission’s inception in 2004, Opportunity studied Endurance Crater, situated close to where it landed, after which it began a journey to Victoria Crater. After it had finished studying the latter, it went on towards the rim of “Marathon Valley” which was named thus after the marathon distance it took the small rover to get there – only 26.2 miles.
Yet Opportunity has had its fair share of problems. Just this year, after a scheduled quick reformatting of its flash memory, the process encountered problems. Now the rover is forced to use only its RAM (random-access memory) to store data collected within a single day.
When night approaches, the rover prioritizes data according to what instructions it receives and then sends only as much as possible until it is forced to shut down during nighttime to conserve energy. John Callas, Opportunity Project Manager, has compared this process with the way a defective refrigerator works – you can only store the food you will eat the same day, so no left-overs. Opportunity wipes its RAM every night before going to sleep, to make room for important data the next day.
In this next Martian winter, Opportunity is set to spend several months, beginning this August, in Marathon Valley, where the sun’s position will be most favorable to its batteries.
Image source: mars.nasa.gov