My favorite Martian

The first Martian (top) sighted on Mars smiles back from the rover’s calibration panel. The panel also features a 1909 Lincoln penny. Look closely at the penny and you’ll see a grain of Mars sand under Lincoln’s ear. It’s only 0.2 mm (.008 inches) across. Geologists classify sand grains this size as “fine sand”. Credit: NASA/JPL-Caltech/MSSS

Curiosity has traveled all of 466 feet along the dust, gravelly floor of Gale Crater since landing on August 6. It’s on its way to Glenelg to scoop up and analyze a soil sample. Earlier this week, mission controllers opened the recloseable dust cover on the Mars Hand Lens Imager (MAHLI) mounted on the rover’s robotic arm and snapped closeups of Curiosity’s underbelly, wheels and calibration target. The camera can focus on objects less than an inch away and acts as a magnifying glass similar to what a geologist would use in the field.

Wide view of Curiosity’s calibration target taken by the MAHLI imager. You can already see the orange coating of  Mars dust. Credit: NASA/JPL-Caltech/MSSS

My favorite photo of the bunch is the calibration target showing color reference swatches, a metric bar graphic, a penny and below it, a stair-step pattern for depth calibration. The 1909 VDB penny harks back to the geologists’ tradition of placing a coin,  rock pick or another object of known size in pictures of individual rocks or rock formations. It gives the viewer an idea of a feature’s size at a glance. Ken Edgett, MAHLI principal investigator, purchased the penny for the mission.

Moving in closer, we see there’s something else in the MAHLI image – a drawing of a Martian waving from a rock!

“Joe the Martian” is a character created by Edgett for the children’s science periodical “The Red Planet Connection” when Edgett directed the Mars outreach program at Arizona State University in the 1990s.

MAHLI photo of the underside of Curiosity with a view out to the horizon. Since the camera can focus anywhere from 0.8 inches all the way to infinity  it can capture both extreme closeups and landscapes. Credit: NASA/JPL-Caltech/MSSS

Joe goes back even further to when Edgett was 9 years old. He drew the character as part of a school project at the time of the 1975 Viking missions to Mars, the first to safely land probes on the planet. It was Viking that inspired him to become a Mars researcher. Joe’s appearance on Mars is most fitting.

Back in the 1960s I enjoyed watching episodes of My Favorite Martian, a TV sitcom about a Martian spaceship that crash lands near Los Angeles. Tim O’Hara, an LA Times reporter, discovers the wreck and the pilot, a Martian anthropologist dressed in a shiny aluminum jump suit. O’Hara nicknames him “Uncle Martin”. Antics ensue. Joe now joins Uncle Martin as my two favorite Martians.

12-mile-diameter Phobos nudges into the sun on September 13. Curiosity aimed its mastcam camera skyward and used a solar filter to take the photo. Credit: NASA

Digging through Curiosity’s stockpile of raw images today, I found this one taken by the mastcam of the moon Phobos partially eclipsing the sun on September 13. Nice bite!

Eclipse is slightly inaccurate. Because Phobos is so small, it’s technically called a transit. The little moon is only 3600 miles from Mars – much closer than the moon is from the Earth – so eclipses (transits) are fairly common.

According to Phil Plait of Bad Astronomy, Phobos crosses the sun about once a year from Curiosity’s site. Scientists  study transits of Phobos and Mars’ other moon Deimos to gauge the thickness of clouds and dust in the atmosphere. More images of the event should show up in the next few days. When they do, I’ll post a higher res version.


Transits of Phobos have been photographed before by the Mars Opportunity Rover. Click the video to see one recorded on November 9, 2010. 

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