Spirit's Dust Dilemma

By Nancy Atkinson - April 30, 2008 at 8:25 AM UTC | Planetary Science
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Steve Squyres and the Mars Exploration Rover team knew from the beginning that dust could cause a problem for the rovers, Spirit and Opportunity. When a thick layer of dust coats the solar panels, it blocks the sunlight that generates power for the six-wheeled robots. In the summer of 2007 a huge dust storm blanketed Mars, and deposited a fair amount of dust on solar panels of both rovers. Spirit, especially accumulated a lot of dust on its solar array. Currently, only about one-third of incoming sunlight is able to penetrate dust on Spirit's solar panels to be converted to electricity. As a result, Spirit is experiencing the lowest energy levels to date and accumulating a backlog of data waiting to be transmitted to Earth.

If only a dust devil would come along!

Spirit's solar array input has been approximately 240 watt-hours per Martian day, or sol (100 watt-hours is the amount of energy needed to light a 100-watt bulb for one hour). The skies in the area are now clear, which means additional dust shouldn't be accumulating on the solar panels, and sunlight should be abundant. But clear skies also mean lower temperatures on the surface of Mars, increasing the bitter cold experienced by Spirit's rover electronics module during the current Mars winter. Nighttime temperatures are creeping closer to the point where they will trigger the survival heaters, which draw a large amount of power.

The rover team has been using the strategy of keeping Spirit awake long enough each day to keep the electronics module sufficiently warm with heat from normal operations, providing more time for science observations. However, recently the team has done less science operations in order to allow Spirit's batteries to recharge. The engineers are being creative in the trade-offs the team makes each day to keep Spirit going through the Martian winter. Another way they are conserving energy is by restricting the number of sols on which Spirit receives direct-from-Earth instructions via the rover's high-gain antenna and transmits data to Earth via the Odyssey orbiter.

The MER team is hoping for a dust devil event to come and clear off the solar panels, like these dust devils did back in 2005.

This image shows the difference in the dust accumulation before and after the dust-cleaning event back in 2005.

And this is a self-portrait the rover took of its cleaned solar panels in 2005. Here's hoping Spirit can be wiped clean again, and the sooner the better.

Original News Source:

Mars Rover website

Nancy Atkinson

Nancy Atkinson

Nancy Atkinson is a space journalist and author with a passion for telling the stories of people involved in space exploration and astronomy. She is currently retired from daily writing, but worked at Universe Today for 20 years as a writer and editor. She also contributed articles to The Planetary Society, Ad Astra (National Space Society), New Scientist and many other online outlets.

Her 2019 book, "Eight Years to the Moon: The History of the Apollo Missions,” shares the untold stories of engineers and scientists who worked behind the scenes to make the Apollo program so successful, despite the daunting odds against it. Her first book “Incredible Stories From Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos” (2016) tells the stories of 37 scientists and engineers that work on several current NASA robotic missions to explore the solar system and beyond.

Nancy is also a NASA/JPL Solar System Ambassador, and through this program, she has the opportunity to share her passion of space and astronomy with children and adults through presentations and programs. Nancy's personal website is nancyatkinson.com