Fascination with Spherules

After nearly a month on Mars for the Opportunity rover, Sol 25’s wake-up music was "Fascination" by Human League. As the rover took it closest views yet of the intriguing outcrop, one of the most surprising elements of the rock matrix is the varied population of spherules. The sphericity and in some cases agglomeration of these bead-like shapes has yet to be understood completely, as scientists look to get enough of them in a single picture that their composition and any internal layers might reveal themselves.

Mars Time

The extensive microscopic images of "El Capitan," offer a close-up view towards a rich science target. The ridge has multiple layers and varied textures on the upper and lower areas of the rocks, implying multiple changes in the geologic history of this area.

On sol 28, which ended at 1:38 a.m. Sunday, PST, Opportunity moved its arm repeatedly to make close-up inspections the "El Capitan" part of the street-curb-sized outcrop in the crater where the rover is working. Opportunity took 46 pictures with its microscope, examining several locations on "El Capitan" at a range of focal distances. It also placed its Mössbauer spectrometer and its alpha particle X-ray spectrometer on the rock target to assess what minerals and what elements are present.

A front hazard camera view of the robotic arm working in the area dubbed "Laguna Hollow." Scientists are intrigued by the bedrock and the triangular, cracklike fine lines, which indicate a coherent surface that expands and contracts.
Image Credit: NASA/JPL

Controllers chose the song "I am a Rock," performed by Paul Simon and Art Garfunkel, as Opportunity’s sol 28 wake-up music. The sol’s activities included observations by the miniature thermal emission spectrometer and the panoramic camera, as well as the use of the tools on the arm.

The arm’s complex maneuvers totaled 25 minutes of actual arm movement. Rover planners’ success in accomplishing them drew a round of applause in the Mission Support Area at JPL during the afternoon downlink from Mars.

During the martian night, early on sol 29, Opportunity woke up and moved its arm again to switch from the Mössbauer spectrometer to the alpha particle X-ray spectrometer. Additional close-up inspections are planned for later in sol 29, which ends at 2:17 a.m. Monday.

Plans for sol 30 [Monday-Tuesday] feature the use of the rock abrasion tool to grind through the surface at one target on "El Capitan."

On sol 27, ending 12:57 a.m. Saturday, PST, Opportunity successfully "supersized" the measurements of the "El Capitan" area with the panoramic camera, miniature thermal emission spectrometer, and microscopic imager. The rover team is analyzing "super resolution" and "super spectral" observations from the science instruments and currently locating the best spots to place the rock abrasion tool.

Opportunity also drove 33 centimeters (13 inches) closer to "El Capitan" to better poise the robotic arm for use of the rock abrasion tool sometime over the next four or five sols, which will be the first use of the rock abrasion tool by Opportunity.

A ‘budding’ spherule, perhaps combined from two differently sized or malleable agglomerates Image Credit: NASA/JPL

The Mars Odyssey orbiter is scheduled to fly over Opportunity during sol 28 with increased data communications capabilities to 256 kilobits per second, which is five times the speed of normal home computer modems.

On sol 26, which ended at 12:18 a.m. Friday, February 19, PST, the rover concluded its earlier work in the trenches it dug and drove 15 meters (50 feet) to the "El Capitan" area. Opportunity successfully obtained one final Mössbauer spectrometer reading of the trench, stowed the rover arm.

The drive was Opportunity’s longest yet and required the vehicle and planners to skirt the trench and avoid the lander.

After the drive, the Opportunity team plans to take a picture of the martian sky with the panoramic camera and miniature thermal emission spectrometer. If time permits, Opportunity will attempt to aim its cameras toward the heat shield in the far distance.

A rear hazard camera view of the exploration tracks inside the Opportunity landing site, crater and landing petal. The total distance from edge-to-edge is about 20 meters in the crater, with the bedrock outcrop covering about half the circumference
Image Credit: NASA/JPL

The mineralogy and geology teams had requested a minimum of three hours worth of "super resolution" and "super spectral" observations for the science instruments to get the most comprehensive coverage of this interesting site, which has varying textures and layers of dirt and rock.

So for this weekend at Opportunity’s rich geological site, the firsts included super-resolution images, the rock abrasion tool, and the rover’s longest drive complete with hazard avoidance of its own relic trench and landing petal.





Related Web Pages

JPL Rovers
Spirit’s Sol images and slideshow
Opportunity image gallery and slideshow
NASA’s RATs Go Roving on Mars
Water Signs
Microscopic Imager
Gusev Crater
Pancam– Surveying the Martian Scene
Mössbauer spectrometer
Alpha Proton X-ray Spectrometer