Scanning Alien Skies: The Roving Astronomers of Mars
Artificially generated depiction of Spirit Mars Exploration Rover on scientific duty. The image uses a photorealistic model of the rover and a false-color mosaic using frames taken by the robot during its exploration within Gusev Crater. Rover model by Dan Maas; synthetic image by Koji Kuramura, Zareh Gorjian, Mike Stetson, Eric M. De Jong. Image
Credit: NASA/JPL-Caltech/Cornell

If you ever wondered what it would be like to stand on Mars and view the night sky, two robots have beat you wheels down.

In "Backyard Astronomy from Mars" carried in the August issue of Sky & Telescope magazine (soon to hit newsstands), author Jim Bell details use of the Spirit and Opportunity Mars rovers to carry out nighttime observations. He is an astronomer and planetary scientist at Cornell University in Ithaca, New York, and is the leader of the Mars Exploration Rover Panoramic Camera (Pancam) team.

In the article, Bell discusses astronomical sight-seeing utilizing Spirit, fresh from a laborious trek up Husband Hill within the Columbia Hills at the robot's Gusev Crater exploration zone.

Thanks to a dust devil blowing away particles that had fallen onto Spirit's solar panels, the intrepid rover became power rich. "We had enough power to run the rover's computer and cameras, and their associated heaters, at night," Bell explains.

"It was an embarrassment of riches," Bell writes. "Several of us on the rover team are astronomers, either professionals or amateurs, and we have always been intrigued by the prospect of stargazing from the surface of another world."

Novel observations

Admittedly, Bell relates, there were numbers of constraints using the robot--and a need to justify use of a $400 million rover for astronomical observations. "It would be stone-knives and bear-skins backyard astronomy--but from Mars!"

Despite the obstacles, a set of novel astronomical observations were made using Spirit. For example, the two Mars moons--Phobos and Deimos--were pictured, with camera filters applied to yield new data about the surface compositions of the red planet's natural satellites.

Stars with known brightnesses were also imaged, allowing researchers to look for evidence of nighttime dust or water-ice clouds wafting about in the thin martian atmosphere.

Long exposure takes by Spirit captured star trails. These images recorded linear streaks, dots, and splotches created by cosmic rays striking the camera's sensitive detectors. The observations can help validate meteor-shower predictions, Bell says, giving scientists useful clues as to the rate of impacts of small meteoroids on the planet.

"Finally, we obtained twilight-sky images from both Spirit and Opportunity," Bell writes. "These include some spectacular views of sunrises and sunsets - useful for analyzing how dust is distributed vertically in the Martian atmosphere, but also just plain beautiful."

During the latter part of 2005, the Opportunity Mars rover on the other side of the planet from Spirit caught Earth and Jupiter rising together before dawn in the eastern sky of Meridiani Planum.

"What an amazing experience," Bell notes, "to be living on one planet and taking pictures of ourselves from the surface of another!"

New campaigns possible

As for the future, Bell told via email that Mars scientists are mostly worried about keeping Spirit and Opportunity alive through the coming martian winter. 

"However, if we are fortunate enough to survive and continue to operate during a third martian summer, we may be able to initiate new twilight or night-time astronomy campaigns on one or both vehicles," Bell explained. These observations could provide additional information on morning or evening clouds and atmospheric dynamics, or astrometric data to further refine the orbits of Phobos and Deimos, he said.

Also, the rovers could be used to perform a longer, more sensitive search for meteors in the martian atmosphere, Bell added, compared to the limited search that was performed in 2005.

Furthermore, Bell said, additional information on the martian surface's harsh cosmic ray environment--which the rover camera system is very sensitive to during night-time imaging observations -- could be used to help the imaging investigations on future missions like the upcoming NASA Phoenix lander and Mars Science Laboratory help design more robust cameras or electronics.

Check out Sky and Telescope for more.