Rover Science Team Eyes Sleepy Hollow

Pasadena, Spirit Mission Sol 3

As they waited for the sun to rise over Gusev Crater on the third sol, or Martian day, of Spirit’s mission, NASA engineers back on Earth reported that the rover was continuing to perform well.

‘Sleepy Hollow’ feature of first panorama, shown in banner at center and in closer view from one piece of the 360 degree panorama.

The Spirit engineering team has established successful communication using all of Spirit’s various communication links. Most of the rover’s scientific instruments – the microscopic imager, the Mössbauer spectrometer and the Alpha Proton X-ray Spectrometer [APXS] – have all been checked out and are working properly. Only the Mini-TES remains to be tested; that test will occur during sol 3.

There was some concern that the Mössbauer spectrometer would fail to function.

"I’ve got to confess," said Steve Squyres, principal investigator for the rover missions, "I was scared about the Mössbauer . This was an instrument that malfunctioned on us during cruise," the journey from Earth to Mars. "Over a period of several months, we managed to find a way to change the way in which we operated the instrument to get it so it was working okay. But I didn’t know what we were going to see when it hit the ground."

In addition to getting a complete physical on sol 2, Spirit sent back tantalizing new images: a complete stereo panorama taken by its Navcams, the onboard cameras used primarily for navigation.

Mission control also received thumbnails of a series of Pancam (panoramic camera) images, indicating that the rover has taken those images and has them stored in its memory. On Monday morning, however, NASA reported that the rover had not yet transmitted the images to Earth. They are expected to arrive some time today and to be released to the public on Tuesday morning, January 6, at 9 am PST.

Over the course of the next few days, Spirit will acquire and transmit a full set of Pancam images. When the Pancam sequence is complete, it will comprise a full-color stereo 360-degree panorama of the site, with 14 times the resolution of the Navcam images. This will enable scientists to view the landing site terrain in much greater detail.

Mars Exploration Rover with main instruments indicated by location on the unfurled instrument after stand-up.

Eventually, image specialists will be able to combine the Pancam imagery with elevation data previously collected to produce a full-color 3D flythrough scenario of the landing site. The elevation data was acquired by the MOLA (laser altimeter) instrument onboard Mars Global Surveyor (MGS), a spacecraft that has been orbiting Mars for several years.

Also expected over the next few days is a complete Mini-TES panorama of the landing site. Mini-TES "sees" in infrared; the images it creates are essentially temperature maps of the scene. Because different materials radiate energy at slightly different temperatures, this information will provide mission scientists with invaluable information about the mineral composition of the rocks and soil at the site.

The science team will use a combination of information from the Pancam and Mini-TES images to decide which rocks are the most interesting to visit once the rover leaves its landing platform. Spirit is expected to roll onto the martian surface in about 8 to 10 days.

The new Pancam design has a camera bar that contains Pancam and Navcam (navigation camera) heads. A "visor" changes the elevation of the cameras so the rover can look up or down.
Credit: Cornell University

Although only limited information is available so far, one feature of the landscape has already fired the imagination of the science team. Dubbed "Sleepy Hollow" – it’s the first feature of the Gusev Crater site to be named – it is a shallow depression in the ground about 30 feet across and about 40 to 50 feet away from the landing platform. Scientists speculate that it is an impact crater that has been filled in with dust or, possibly, with sediments that date from the time when Gusev Crater may have held a lake.

How soon Spirit will get a chance to take a closer look at Sleepy Hollow depends on what the Pancam and Mini-TES images reveal.

"Right now we have very little knowledge about the variety of color, the variety of texture, the variety of composition that we have at the scene. If Pancam and Mini-TES tell us that we have some significant compositional variety, different kinds of rocks available to us, we could conceivably visit at least a couple of those before we start motoring off to a place like Sleepy Hollow," said Squyres.

If, however, the landing site appears more uniform, Spirit will take a close look at a typical rock and then make a beeline for Sleepy Hollow.

"It’s conceivable," Squyres concluded, "that something glorious will pop out in the Mini-TES data that will cause us to go someplace completely different. But right now, Sleepy Hollow looks like the place to be."

Related Web Pages

Water Signs
Microscopic Imager
Gusev Crater
Pancam – Surveying the Martian Scene
Mössbauer spectrometer
Alpha Proton X-ray Spectrometer
Mars Rover: The Owner’s Manual