In the vast expanse of space, a unique celestial event brings a temporary hush to the constant stream of data flowing between Earth and its robotic explorers on the Red Planet. Approximately every 25 months, Mars and the sun find themselves on opposite sides of the sky, and the sun’s corona acts like a cosmic veil that scatters and distorts radio signals that traverse this vast interplanetary void.
The latest episode in this drama played out this month. NASA’s rover Opportunity fell silent in June when a massive dust storm swirled over the planet’s surface and engulfed her solar panels. Her power levels quickly dwindled to the point where she entered a “low power fault mode,” she’s been in limbo ever since.
Curiosity, the surviving rover, was not so lucky. After a year of cruising around Mars, the robot stopped sending data back to mission control. The problem is simple: the rover relies on solar power for its energy, and after four years on the Red Planet, its sunlight-collecting panels are coated with so much dust that the lander cannot generate enough electricity to send data home.
InSight, the lander designed to study Mars’ geologic life story, has also fallen silent. The instrument-laden lander’s solar panels have been so covered with dust that it no longer can generate enough power to operate, and its ground controllers at California’s Jet Propulsion Laboratory were expecting InSight to go dark eventually. They’ve already started preparing for the inevitable and have uploaded weeks’ worth of instructions to InSight so that it can run autonomously.
Scientists gathered plenty of new information from the rovers, with instruments that mapped elevations of canyons and craters, detected remnants of Mars’ ancient global magnetic field, and recorded yearly changes in the cold, arid climate. Opportunity’s greatest gift, Cornell University scientist Steve Squyres says, was providing a geologic record at two locations on the Red Planet, showing that briny water once sloshed about in environments ripe for early microbial life.
Squyres calls the rover’s death an honorable end. The rover had survived many obstacles over its 14-year life on the Red Planet and, in the end, succumbed to one of the harshest environments that could kill it.
Even with the rovers and lander on hiatus, engineers have a lot of work to do. Orbiters like Odyssey and the Mars Reconnaissance Orbiter will continue to take surface images, and satellites such as MAVEN will study interactions between the Martian atmosphere and the sun. Once the conjunction period is over, the rovers will start up again, and the fleet will begin sharing their findings with Earth. For now, though, engineers have turned their attention back to their stalwart crew members on the Red Planet. They’re preparing them for the dark times ahead and will upload their week’s worth of instruction to ensure they can still carry out the missions they were sent there to do.
