Operations Scaled Back In Effort To Conserve Power
A giant dust storm that
has been brewing for more than a week on Mars is worsening and is
affecting surface operations of the Mars Exploration Rovers, Spirit
and Opportunity.
Because the rovers depend on solar energy for survival, and the
dust is partially blocking the sun, the storm is being watched
closely by the rover scientists and engineers, according to the
National Aeronautics and Space Administration. Opportunity's entry
into Victoria Crater, as reported by ANN, is
delayed for at least the next several days.
The space agency says this is the most severe storm yet to hit
the rovers and it is expected to continue for at least another
week. Opportunity is perched near "Duck Bay" as it prepares to
descend into the crater, but operations were scaled back on June 30
to conserve power.
"The storm is affecting both rovers and reducing the power
levels on Opportunity," said John Callas, Mars Exploration Rover
project manager at NASA's Jet Propulsion Laboratory in Pasadena,
CA. "We are keeping an eye on this as we go forward, but our entry
into Victoria Crater will be delayed until no sooner than July
13."
"We have some data that show the atmospheric opacity is
decreasing, so the storm might have peaked and we may have passed
the worst of this," he said. "The situation could improve quickly
from here, but we will have to wait and see."
Weather reports from NASA's Mars Reconnaissance Orbiter Mars
Color Imager camera are helping track the storm and plan rover
operations.
Pictures from the orbiter's Mars Color Imager show the storm is
regional in extent, and includes several local areas of especially
high dust activity. The storm has been moving eastward and toward
mid-latitudes, and is now also causing an increase in atmospheric
dust at Spirit's location, on the opposite side of the planet at
Gusev Crater. Dust levels at Gusev remain much lower than at
Victoria, however.
Both rovers take daily measurements estimating the amount of
dust in the atmosphere. The less dust the better, because it means
more sunlight reaches the rover's solar panels, which power the
vehicles. In the last week, Opportunity has broken its dust record,
with the opacity level rising from 1.0 to 3.3. Solar array energy
on Opportunity dropped from 765 watt-hours to 402 watt-hours over
the same period of time.
"While this only represents enough dust to coat the planet to
about the thickness of a human hair, it is enough to decrease the
brightness of the noon sun by 96 percent compared to a completely
clear atmosphere," said Steve Squyres, principal investigator,
Cornell University in Ithaca, NY. "Of course, the solar arrays also
receive light that is scattered from the dust, so the decrease in
power is not nearly that great."
"We have not seen dust measurements this high on either rover
before," said Callas. "If the dust levels were to increase further
and stay elevated for several days, there is a risk to how well
Opportunity could continue to work in this darkened
environment."