During the second day on Mars for NASA’s Opportunity rover, key science instruments passed health tests and the rover made important steps in communicating directly with Earth.

Halfway around the planet, during its 22nd day on Mars, NASA’s Spirit obeyed commands for transmitting information that is helping engineers set a strategy for fixing problems with the rover’s computer memory.

On Earth this morning, scientists marveled at a high-resolution color “postcard” of Opportunity’s surroundings. The mosaic of 24 frames from the panoramic camera shows details from the edge of the lander to the distant horizon beyond the rim of the rover’s small home crater.

“We’re looking out across a pretty spectacular landscape,” said Dr. Jim Bell of Cornell University, Ithaca, N.Y., lead scientist for the panoramic cameras on Spirit and Opportunity. “It’s going to be a wonderful area for geologists to explore with the rover.”

The color view shows dark soil that brightened where it was compacted by the rolling spacecraft, and an outcropping of bedrock on the inside slope of the 20-meter (66-foot) crater in which the rover sits. Opportunity will be commanded to finish taking a 360- degree color panorama of the site during its third Mars day, which began at 12:01 p.m. PST today.

Another major step planned for Opportunity’s third day is to begin using its high-gain antenna for communicating directly with Earth at a high data rate, said Jackie Lyra of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., activity lead for this rover event. In preparation for this transition, Opportunity found the Sun with its panoramic camera yesterday. Once oriented by knowing the position of the Sun, it can calculate how to point its high-gain antenna toward Earth.

“We’re making steady progress in our effort to get the wheels of the rover dirty,” said Mission Manager Jim Erickson of JPL. Still the earliest scenario for the rover to drive off its lander platform is more than a week away.

Opportunity has tested the three scientific sensing instruments on its robotic arm that will be used for up-close examination of rocks and soil: the microscopic imager, the alpha particle X-ray spectrometer for determining what elements are present, and a Moessbauer spectrometer for identifying iron-containing minerals. “I’m pleased to report that all are in perfect health,” said Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the science instruments on the rovers.

Squyres had been especially concerned about the Moessbauer spectrometer because tests conducted while the spacecraft was on its way to Mars showed that an internal calibration system was not working as intended. However, after the rover landed on Mars, the instrument is functioning normally again. The Moessbauer spectrometer’s function for identifying iron-bearing minerals will be important in the scientific goal of determining the origin of iron-bearing hematite deposits in the Meridiani Planum region selected as Opportunity’s landing site.

“We have a perfectly functioning Moessbauer spectrometer, and given that we are now perched atop the hematite capital of the Solar System, that’s a good thing,” Squyres said.

Restoration efforts continue making progress on Spirit. “We have a patient in rehab, and we’re nursing her back to health,” said JPL’s Jennifer Trosper, mission manager.

Engineers found a way to stop Spirit’s computer from resetting itself about once an hour by putting the spacecraft into a mode that avoids use of flash memory. Flash memory is a type common in many electronic products, such as digital cameras, for storing information even when the power is off. The rover also has random- access memory, which cannot hold information during the rover’s overnight sleep. One of the next steps planned is to erase from flash memory the files stored there from the spacecraft’s cruise to Mars from Earth. That is intended to lessen the task of managing the flash memory files.

The rovers’ main task is to explore their landing sites during coming months for evidence in the rocks and soil about whether the sites’ past environments were ever watery and possibly suitable for sustaining life.

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA’s Office of Space Science, Washington, D.C. Images and additional information about the project are available from JPL at http://marsrovers.jpl.nasa.gov and from Cornell University, Ithaca, N.Y., at http://athena.cornell.edu.