To recap some of the current Martian events, here's where I think we are with Spirit and Opportunity:
Pete Theisinger, project manager for the Mars Explorer Rover Project, said today he feels good enough about the state of things with the Spirit rover that he's likely going to be turning over the regular press conference duty to Jennifer Trosper, Spirit's mission manager for surface operations. I think this is a really good sign that things have turned the corner for MER-A.
Pete went into a little bit of detail about the efforts to track down the problem on Spirit. It sounds like there are three hypotheses. In descending likelihood they are: a) that the software which handles file management for the flash memory is not robust enough for the activities they've attempted to use it, b) that there exists some problem with one of the motor control boards, or c) that a recent, heavy, ion or neutron solar event caused problems writing to or reading from the flash memory.
It sounds increasingly likely that the problem is in software, and not in hardware as had been previously suspected. If the problem is in software, then it is likely to also be a problem for Spirit's (slightly) older sibling, Opportunity. Pete suggested that if it is determine to be a problem in the file system code, they may either devise and enforce a set of rules that avoids whatever failings exist in software, or they may patch the software to correct the flaw. Either of those solutions, Pete said, could give us "a very good rover when we get back up."
Right now, the team has a system in place that allows them to wake the rover without using the flash, and command the rover to test various components and return results to the team. The most recent data seems to have exonerated the flash memory (hardware) and the team has been working in the high-fidelity rover and software testbeds to try to reproduce the filesystem failures. Spirit's basic subsystems -- Power, Thermal, and Communications -- all seem to be in good shape. Pete estimates that Spirit could be rolling again in two to three weeks.
Opportunity, a.k.a. MER-B, touched down with a very gentle landing at Meridiani Planum just about 20 hours ago. The lander rolled to a stop with the +Y petal down. Landing on that back petal means she had to perform a first-time maneuver of lifting that petal to tilt and flip the lander onto its base petal. First-time maneuvers, of course, carry some extra risk, but this + Y landing had the advantage of ensuring that the airbags would all be fully retracted in the forward direction and that will dramatically simplify the egress maneuver.
The lander and rover currently sit facing north-northeast, nose pitched slightly up at just over 5°. The deck height is somewhere between 13 and 16 inches which is well within the rover's rolloff capabilities.
Opportunity has been sending back telemetry and, as of this afternoon's press briefing, all sub-systems are polling green. She's also sent back lots of great images from the DIMES camera, the hazard avoidance cameras, the navigation cameras, and the panoramic camera system.
The DIMES images will allow the project team to get a rough determination of the rover's location, but the real deal for location will come when Mike Malin trains his Mars Orbital Camera (on board the Mars Global Surveyor orbiter) on the area. If things go as well for Mike as they did in his Spirit imaging, we should have Opportunities location to within a couple of feet.
The navigation and panoramic camera systems have returned about 150 images which have the science team "flabbergasted, astonished, blown away". Steve Squyres, the principal investigator for the Mars Exploration Rover program, said at today's press briefing, "we've scored a 300 million mile hole in one". The landing put Opportunity into a small and shallow crater, one that shows both an exposed, layered outcropping of bedrock, and a surface coating of fine-grained hematite. Additionally, the DIMES images suggest that Opportunity is well within driving distances from a much larger crater which is probably rimmed with this layered bedrock. When asked if he could have dreamed of a better landing site, Steve said, "this is exactly what it looked like in my wildest dreams."
Opportunity will be going through a cautious impact to egress process over the next couple of weeks. We can look forward to full-frame, color, stereo Pancam pictures arriving in the next day or two and maybe some Mini-TES data too.
Wow. I'm excited. We have two rovers, each packed with an amazing suite of exploration and investigation tools, sitting on the surface of Mars. We have a best in the world mission team and science team at NASA/JPL. We have an awesome information distribution mechanism in the internet. I couldn't be happier :D
Posted by asa at January 25, 2004 06:58 PM
I'm surprised Pete hasn't made the point that *if* the problem is in software, that is a great advantage because they had an exact bit-for-bit copy of the software here, and they can examine it thoroughly, and test any fixes they might provide.
Not so with hardware - they only have the testbed, which may be close, but it is not an atom-for-atom copy :-)
I'm really glad this site shows some diversity of the martian terrain. To my untrained eye, all of the landing sites (viking, pathfinder and spirit) all looked the same to me :-). This is definitely different.
I hope they get the courage to fly some balloons in another mission, or land in a canyon or something.
