Phobos in transit. (Credit: NASA/Cornell/JPL/Texas A&M)
I never get tired of catching a glimpse of the sky from other vantage points in the solar system… today, as residents of the Old World enjoy a partial solar eclipse on Earth, we thought we would direct your gaze to an eclipse from Mars. On November 10th, 2010 the NASA rover Opportunity caught a unique transit of the Martian Moon Phobos in front of the Sun. The video was shot with the rover’s panoramic camera, and covers 10 frames over a span of 32 seconds. Note that although the Sun is visually smaller as seen from Mars- Phobos only covers about a third of its disk. Visually, Phobos appears about 8-12’ in size from the surface of the Red Planet. You can even make out an outline of the moon’s distended shape! Although the rovers were not designed for extraterrestrial stargazing, the Pancam served well in this regard, and data from these observations will aid scientists in modeling the orbits of the twin moons Phobos and Deimos. Phobos orbits Mars every 7.7 hours and Deimos every 30.1 hours. Both were discovered by Asaph Hall in 1877 and are most likely captured asteroids. The status of these two moons aren’t permanent, as both are on a slow ‘death spiral’ to impact Mars millions of years in the future. A Russian sample return mission dubbed Phobos Grunt aims to launch in late 2011 to early 2012 with a goal of conducting a sample return after ‘landing’ (or do you say docking?) on Phobos.
Rover Opportunity is currently exploring the environs of the 262 foot diameter Santa Maria crater. Contact was lost with the now stationary Spirit rover in early 2010, although periodic attempts have been made to re-establish contact. Peak solar isolation for Spirit will occur on March 2011, and it’s thought that there may be a slight chance that the rover may receive just enough charge to wake up and phone home…both have well passed their 6 month warranty expectations since landing in 2004. Free Spirit!