I frankly thought that NASA was paving the way for an announcement that the two Mars rovers, Spirit and Opportunity, would not survive the huge Martian dust storm that enveloped the planet when they announced this.
The storm presents perhaps the rover team's biggest challenge, NASA said in a statement today. Scientists said the storm, which has been brewing for nearly a month, is blocking around 85 to 90 percent of all sunlight to the surface.
The rovers, Opportunity and Spirit, rely on sunlight to charge their solar panels, and one or both rovers could be damaged permanently or even disabled by the limited solar power, officials said.
SPACE.com reported the storm's fresh severity earlier today.
Scientists fear the storms might continue for several days or weeks. If the sunlight is further slashed for an extended period, the rovers will not be able to generate enough power to keep warm and operate at all, even in a near-dormant state, the statement said.
That was on July 20th. Today, however, NASA announced that both rovers managed to make it through the storms and are still functional – albeit with a very much depleted energy supply. Not bad for two devices that were originally only supposed to run for a few months. More than three YEARS on, and they are still plunking away.
With skies gradually brightening, the solar-powered rovers Spirit and Opportunity recently resumed driving and other operations that had been suspended during the dust storm.
"The rovers are in good health and in good shape," said John Callas, the rover project manager at NASA's Jet Propulsion Laboratory in Pasadena. "Things have improved from the more dire conditions that were existing previously due to the dust storm on Mars."
During the storm, each of the rovers spent a couple of weeks sleeping most of the time.
"They were in sort of a hibernation state where we were only communicating with them every few days," Callas said Friday. "The rovers would only be awake a very short amount of time each day to save power."
The major concern was whether the rovers would have enough energy to keep sensitive electronics at proper temperatures on the frigid planet.
"At the darkest part of the storm, Opportunity had only 128 watt-hours of energy. Today, it has about 350 watt-hours of energy, so almost three times as much now," Callas said. "The most energy that the rovers have ever seen in their 3 1/2 years on Mars is about 900 watt-hours of energy."
Spirit, especially, is in a bit of trouble. It is really struggling with power – perhaps its solar panels are fouled with dust. It may not make it through the Martian winter. But who knows with these rovers. They have been astounding all of us for years now.