Because of the gigantic dust storms on the planet the two twin MERs—Spirit and Opporunity—were unable to function at normal capacities because little sunlight could pierce the storm of dust particles that swirled above them—which made it impossible for their solar arrays to generate enough electricity to power them.
Ground controllers on Earth were forced to power the two rovers down into a low-power mode, even into a hibernation mode, while the strong dust storms whirled around them. A small amount of sunlight did get through the haze of the storms to provide minimum power to perform just the basic of functions for the rovers. Now with the dust storms over, the winds are helping to remove the dust that has collected on the solar panels, helping to restore their ability to generate needed electrical power.
At their peak, the rovers generated about 900 watt-hours of energy, while at their lowest—during the height of the dust storm—Opportunity only generated about 128 watt-hours. This week, Opportunity had about 350 watt-hours.
The 2,400-foot (750-meter) wide Victoria Crater, an impact crater, is located in the Meridiani Planum area of Mars. Scientists working on the MER mission hope that the exposed rock, which is found about 40 feet (12 meters) inside the rim of Victoria Crater, will provide first-time information on the geological history of Mars, which spans millions of years. Impact craters are especially important because they expose layers of soil beneath the surface. Opportunity is expected to explore Victoria for up to one year.
Before the six-wheel rovers Opportunity and Spirit continue their scientific missions, ground controllers at the NASA Jet Propulsion Laboratory (Pasadena, California, U.S.A.) will test their instruments to make sure they are still operating properly after the dust storm.
The rover Spirit is on the opposite side of the planet, in an area of layered bedrock called Home Plate, located near the 545-foot (170-meter) Gusev Crater, an old lake bed partially filled with sediment.
With the intended mission of the rovers to be only three-months, the two robots have been exploring Mars for over 3.5 years. The rovers traveled about 300 million miles (485 million kilometers) in 2004 to reach Mars.
Some of the problems experienced by the rovers are written up in the iTWire article “Power depleted Martian rovers caught by expanding dust storm”.