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PASSPORT TO KNOWLEDGE - To MARS with MER
When the going gets tough, the tough get going.
When the going gets tough, the tough get going. That's what's happening now at NASA JPL: as if landing a second spacecraft, Opportunity, on Mars were not difficult enough, the Mars Exploration Rover team is experiencing serious difficulties with Spirit, already on the ground at Gusev Crater. Spirit was going to be given a planned rest during Opportunity's landing and first days on the surface -- though this kind of spell of "intensive care" was in no-one's play book -- in order to allow full attention to today's inherently risky events. But the Jan 23 briefing was evidence of the quality and commitment of the mission team: project manager, Pete Theisinger, was calm and forthcoming: yes, there were serious communications and possibly hardware problems with the spacecraft (see JPL releases linked in below) but a dedicated team of engineers was carefully working through data to come up with answers, while a separate team was attending to the Entry, Descent and Landing, or EDL, of Opportunity (set for the evening of Saturday Jan 24, Pacific time.) Most of the questions, naturally, were about Spirit, which unfortunately eclipsed the amazing information and images in the reports of Wayne Lee, Miguel San Martin and Adam Steltzner: for the past few weeks, they and colleagues have been working on a "reconstruction" of Spirit's EDL, in order to fine tune that for Opportunity. They've been able to get to incredible detail, including data that the Descent Rate Limiter (controlling the unspooling of the bridle linking the lander to the backshell) took 11 not the expected 6 seconds to deploy. Their information about the number and direction of the bounces also allowed them to determine exactly where Spirit came to rest: equally astonishing images from the Mars Orbital Camera aboard the Global Surveyor allowed MOC camera PI, Mike Malin, to show where the parachute and backshell, the heat shield, and Spirit herself came to rest. Check out the images for evidence of how powerful the combination of software, hardware and human ingenuity can be. Spirit's communications difficulties are serious and as yet mysterious: not even Pete Theisinger could predict if and when progress might be made. But the Rover mission team are tough and dedicated: if anyone can figure out the problems and fix them, it's them. Stay tuned for news from Opportunity and soon, we hope, once more from Spirit.
Gear on Opportunity Rover Passes Martian Health Check
January 26, 2004
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.
Image Credit: NASA/JPL/Cornell University
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.
