Victoria’s Secret

Courtesy of Aviation Week & Space Technology and Aviationnow.com

Opportunity to unravel ancient mysteries as other Mars missions face new escapades

The Mars Rover Opportunity is beginning complex and dangerous science operations 242 million mi. from Earth at the massive Victoria crater, the most spectacular and potentially significant target of the entire $800-million twin-rover Mars surface exploration mission.

“We are frankly feeling a little overwhelmed by what we see so far,” says Steve Squyres, rover principal investigator on his Cornell University web site.

Opportunity has been driving at the the speed of a tortoise for 5.7 mi. and almost three years to reach the 2,500- ft.-dia., 230-ft.-deep crater. Every inch has been a marvel of autonomous robotics and dedicated command and control by Pasadena, Calif.’s Jet Propulsion Laboratory (JPL), as well as 24/7 planning by a dispersed international science battle staff led by Squyres and Deputy Principal Investigator Ray Arvidson at Washington University in St. Louis. The teams have been preparing for almost two years for their arrival at Victoria.

From a position about 8 ft. from the rim, one can see 0.5 mi. to the far side of the crater, framed by rocky cliffs. The crater’s rim comprises alternating promontories, recessed alcoves and rocky points towering 230 ft. above the bottom of the crater. Martian windcarved sand dunes cover the crater floor.

For this Navcam panorama above, colorized by outside analysts, Opportunity was about 8 ft. from the lip at Duck Bay alcove.

Click on image to enlarge (1.6mb 200 dpi image)

NASA/JPL NAVCAM Imagery Merged and Color Coded by Bernhard Braun, Marco Di Lorenzo, Ken Kremer and Doug Ellison. Reprinted courtesy of Aviation Week & Space Technology and Aviationnow.com

The rover has made dozens of sampling stops over the last 21 months. At the mission’s outset, no one dreamed that Opportunity could reach Victoria, imaged well south of the landing site by the Mars Global Surveyor orbiter.

“We’re so proud of Opportunity, the rover that ‘takes a lickin’ but keeps on tickin,'” says Cindy Oda, a Mars rover mission manager at JPL. “It continues to overcome all challenges despite its aging parts and difficult terrain. We are looking forward to exciting new discoveries as Opportunity begins its new adventures exploring Victoria crater.”

The trip began in earnest after several months spent in Endurance crater in mid-2004. The team could hardly believe Opportunity survived that, let alone reach Victoria, five times bigger than Endurance. Victoria was carved out much deeper by a large meteorite perhaps more than a billion years ago. Researchers believe Victoria has the potential for revealing once deeply buried rock layers as evidence of possibly abundant, perhaps life-sustaining water. Layers 200-ft. deep may be exposed, compared to 25-ft. layers at Endurance.

Victoria is 40 times larger than Eagle crater, where Opportunity made initial stunning discoveries in only 1.5-ft. layers about the permanence of Martian water, which is a key to the formation of life, if it ever existed, on Mars.

Victoria’s secrets are buried in the rock layers; the more layers, the more detailed the story. “This is a geologist’s dream come true,” says Squyres. “Those layers of rock, if we can get to them, will tell us new stories about the environmental conditions long ago. We especially want to learn whether the wet era that we found recorded in the rocks closer to the landing site extended farther back in time. The way to find that out is to go deeper, and Victoria may let us do that.”

Opportunity’s arrival at Victoria kicks off a very busy period of Mars exploration this month involving three U.S. and one European orbiter, along with preparations for another U.S. lander. The main events involve:

• The Mars Reconnaissance Orbiter (MRO): The most powerful planetary imaging spacecraft ever flown is this week in the midst of its initial high-resolution Mars science-imaging after the completion of aerobraking to reach its low-altitude science orbit (AW&ST Sept. 25, p. 21).

“This is truly a significant moment for the MRO team,” says Jim Graf, MRO project manager at JPL, which is commanding the spacecraft with Lockheed Martin near Denver.

MRO’s first priority target will be the proposed northern polar region landing site for the NASA Phoenix lander. Phoenix is less than a year away from launch to Mars from Cape Canaveral on a mission to dig for subsurface ice that may hold clues to the potential for life in that specific environment.

The MRO University of Arizona High-Resolution Imaging Science (HiRISE) camera, coupled with a suite of other sensors, was to relay its first lowaltitude images Sept. 29 and continue through this week. The objective is to image the Phoenix site for landing obstructions as early as possible.

“We want to image it while the area is still fully illuminated,” Graf says. “There is a period of solar conjunction coming when the Sun will block signals from Mars. If we wait, the imaging will start degrading—but the Phoenix team needs the data this October.”

The imaging through Oct. 6 will also be the first time that MRO will use its onboard targeting algorithms to point at desired targets on Mars.

• Phoenix: The NASA/University of Arizona Phoenix lander with its powerful digging arm, developed by Alliance Spacesystems Inc. in Pasadena, and miniature sample ovens is itself undergoing major hardware buildup at Lockheed Martin.

• Europe’s Mars Express: Mars Express is just emerging from a period where its solar arrays could not generate power because Mars blocked the Sun for up to 75 min. at a time. This occurs periodically, but was especially serious in late September, when complications from an earlier failure prevented full battery charging even when the Sun was in view. “This was potentially critical, and we knew we had to devise a solution that wasn’t in the manual,” says Michel Denis, Spacecraft Operations Manager at ESA’s Space Operations Center, in Darmstadt, Germany.Systems were turned off and, at times, the spacecraft pointed away from Earth and its critical communications link with Darmstadt. The spacecraft was forced into survival mode. The Mars Express prime contractor, Astrium, in Toulouse, France, worked closely with ESA, providing detailed information and conducting a parallel study to cross-check and verify the survival procedures. The effort worked, and Mars Express is this week getting back to normal imaging operations.

• Mars Global Surveyor and Mars Odyssey: Global Surveyor, which arrived at Mars in 1997, and Odyssey, which began specialized imaging in 2001, are being budgeted for two more years each, says Doug McCuistion, NASA’s Mars Exploration Program director.

Odyssey has also made a remarkable new discovery about Mars. New analysis of data from its Raytheon Thermal Emission Imaging System, operated by Arizona State University, has found that violent gas eruptions occur every spring around the south polar ice cap.

Jets of carbon dioxide erupt at 100 mph. from the ice cap as it warms, carrying dark sand and dust high aloft. “The dark material falls back to the surface, creating dark patches on the ice cap, which have long puzzled scientists,” says Phil Christensen of Arizona State University, principal investigator for Odyssey’s camera. “All around you, roaring jets of carbon dioxide are throwing sand and dust a couple hundred feet into the air.”

Both the rovers Spirit and Opportunity are also getting one-year budget extensions into early 2008. The original Victoria sailed into exploration history in 1522 as the only ship under captain Ferdinand Magellan to circumnavigate the globe. Now, the ship’s namesake will be the focal point of at least a year of rover exploration on the surface of Mars—a mission so important that Opportunity may spend its final days there, perhaps sacrificing its life for science in a “crater-to-grave” scenario to reach rock layers so deep in the crater that the rover may not escape.

But rover drivers at JPL are this week much more concerned about a “Thelma and Louise” scenario where the rover could fatally drive over the extremely steep edges of the cliff. It will be navigated as it uses commands from Earth and its own autonomous robotic navigation to move slowly near the rim.

Before the trip around the crater, JPL will command the rover to creep onto a promontory to spend several days taking a highly detailed Pancam image that will provide scientific data and vivid imagery to map future operations.

It will also bag major early findings, just in case anything goes awry on the jagged edge of the crater.

In late September, as Opportunity approached Victoria, the team performed a crucial software change. On Sept. 20, JPL rebooted the rover computer after loading the new flight software. Fortunately, the rover awoke that afternoon with the software functioning normally.

“This new software is going to be a pretty big deal for us,” Squyres says on his web site. “It includes lots of new capabilities, things that we’ve figured out over all these sols [Martian days] that we have now taught the vehicle to do with this software. One capability is ‘go and touch,’ the ability to send the rover to a target and deploy the arm onto that target all in one sol. That’s something we’ve never done on Mars before. Another is automated dust-devil finding, which should be pretty cool if Spirit is still hanging in there by summer. And there are a bunch of other things, too. The rovers are getting older, but they’re suddenly a whole lot smarter,” he says.

NASA chose to boot the new flight software when it did because “in a few weeks we will go into ‘superior conjunction,’ when Mars goes out of sight behind the Sun,” Squyres says. “There will be a stretch of time when we can’t send commands to the rovers at all, and during that time we want to have complete, unequivocal confidence in the software that’s on board.”

Spirit has also received a new software load. Halfway around Mars and farther south of the planet’s equator, Spirit has been staying at one northwardtilted position through the southern Mars winter for a maximum energy supply to its solar panels.

In the meantime, Spirit is conducting studies that benefit from staying in one place, such as monitoring effects of wind on dust. It will begin driving again when the Martian spring increases the amount of solar power available.

When it landed in January 2004, Opportunity, and its twin, Spirit, on the opposite side of the planet, had specification lifetimes of 90 days and 2,000 ft. of driving.

Opportunity’s ability to survive and reach Victoria far from its original landing site, and Spirit’s ability last year to climb to a Martian mountaintop, will live long in planetary science and rank among the great achievements of the U.S. robotic space program.