Mars Rover Spirit Sends First 360-Degree Color Panorama 'Postcard' and Prepares to Roll onto Martian Surface
As Spirit slept soundly after another near-perfect day of picture taking, science gathering, and data relays from Mars, NASA released the first color 360-degree panorama postcard it sent home. The image reveals a broad landscape, rich with all kinds of scientifically tantalizing targets from nearby rocks to rolling hills out on the horizon, to the shallow depression known as Sleepy Hollow.
"The whole panorama is there before us," said rover science-team member Michael Malin of Malin Space Science Systems, based in San Diego. " It's a great opening to the next stage of our mission, which is to get off the rover and start moving out into this field."
The robot geologist will be awoken later tonight Earth time -- morning on Mars -- to begin the next sequences of maneuvers that will position it to roll off the lander. Roll off is still scheduled for the early morning hours, Pacific Standard Time, Thursday morning, or Sol 12 on Mars.
The color panorama is a mosaic pulled together from 225 frames taken by Spirit's PanCam [panoramic camera], the stereovision color camera mounted atop its mast. The image spans 75 frames across, three frames tall, with color information from shots through three different filters (red, Green, blue).
Assembled "by more than 25 scientists and engineers of the Pan Cam team and others at JPL and various institutions," the image represents "a humongous amount of data [collected] over a 3-sol period -- Sols 3, 4, 5," said Michael Malin Science Team Member at Malin Space Science Systems.
The images were calibrated at Cornell -- the homebase for PanCam lead scientist. Jim Bell. They were then transferred back to JPL where they were "projected into a map projection for assembly" by JPL's multi-mission image processing laboratory and assembled just a few hours before the daily morning press briefing, added Malin who completed the final balancing.
Beyond being 'cool' to look at, these images are of great value and use to the scientists. "Seeing the panorama totally assembled instead of in individual pieces gives you a much greater perspective for the position of things and helps in developing a sense of direction," offered Malin. "I find it easier to visualize where I am on Mars when I can look at different directions in one view. For a field geologist, it's exactly the kind of thing you want to look at to understand where you are."
Another new image from Spirit reveals a close-up look at what scientists conclude to be drag marks created by the retracting airbags, and, specifically, the large patch of unusual [surface] features that resulted from the stress exerted by the airbag scraping against on the soil, which the science team has dubbed Magic Carpet.
"This is really quite a surprise because you can see a patch where the soil detached and was removed and that piece then advanced forward and formed this curl-up structure," explained said science-team member John Grotzinger, of Massachusetts Institute of Technology. "It has been detached and folded like a piece of carpet sliding across the floor. What's so fascinating is that it doesn't exhibit the brittle deformation exclusively that you saw at Pathfinder and Viking, but instead we also see a more ductile plastic form of deformation in that feature." It's a scientific problem the scientists "can't wait" to start working on," he added.
All systems continue to be 'go' for Spirit to roll-off according to the plan announced yesterday. The planned sequence is the cutting of the last cable that connects the rover to the lander, then a turn in place of 115 degrees clockwise, completed in three steps, over the next two sols, Sols 10 and 11 [Monday night/Tuesday morning, and Tuesday night/Wednesday morning Earth time]. If no obstacles are seen from images taken partway through that turn, Spirit will roll off toward the northwestern compass point of 286 degrees.
"We're about to kick the baby bird from the next. We're about to kick the baby bird from its nest," smiled Kevin Burke, lead mechanical engineer for the rover's egress off the lander, who has waited three years for this moment. After cutting the last cable - what is, in essence, Spirit's umbilical cord - using another one of the some 130 pyrotechnic devices with which the rover was equipped or "an explosive guillotine," as Burke calls it, the mission team will "initiate egress activity."
The first move Spirit will make is "an egress bump, " Burke said. "This is a -25 centimeter drive in the rear direction and is used to get rover centered on the deck obstacles that we're going to be spinning over the top of. At the end of the bump, we'll tow in the wheels, so we can initiate a turn in place. That is going to let us know that all of our mobility actuators are functional . . . we do have four actuators as of yet that we don't if they work or not because they haven't been used - so [this will be] our first opportunity to check them out."
Following the bump, Spirit will then turn in place 45-degrees. "The reason we're going [to do this] is to assess the blind spot we cannot see," Burke explained. "Our solar arrays on the right hand side cover up a spot of the soil that we have no knowledge of at this moment." This first turn, then, is "a safe move" that would allow the team, if necessary, to turn back forward if they find something that looks like it might threaten Spirit's roll off in that direction. "It also allows us to assess the performance of the drive actuators," he added.
The following day, Sol 11 on Mars, Spirit will execute the remaining two turn in places to put Spirit in the position engineers have determined is best for egress on this chosen path. On her second turn-in-place, Spirit will move from 45-degrees to 90-degrees.
At the end of this second maneuver, the team will again stop to make sure the rover is in the right spot on the lander deck to continue. "This also the best position that we're going to be in to adjust the rover position on the deck should we need to do so prior to reaching our final position," noted Burke. The last move of that same day will be the third and final turn-in-place, from 95-115 degrees.
"The very next day -- Sol 12 -- we will be driving straight ahead at 115-degrees angle off the deck to the right hand side [northwest]," Burke confirmed. By comparison to Sojourner, the Mars Exploration Rovers are speedy robots. Once Spirit is ready to make her move off the Columbia Memorial Station, it will take her just 75 seconds to roll down the ramp and out three meters, which will put her rear wheels approximately one meter away from ramps and onto Martian soil.
Meanwhile, Spirit is still a little "toasty" inside. "We've been building in siestas in the afternoon or deleting afternoon UHF communications sessions to deal with that," said MER Project Scientist Joy Crisp, who noted as has previously been noted, that the thermal situation will change when the rover drives off onto the surface of Mars. "We expect then the rover will not require a siesta once it off the rover," she added.
In addition, the mission team is keeping an eye on the predicted temperature change each day in the ground surface temperature, the near surface air temperature, and the sky temperature, using a thermal model of the Red Planet developed by Jim Murphy, of New Mexico University.
The team gave Murphy the various input parameters of surface reflectants and thermal inertia [ the resistance to change in temperature], and estimate of dust abundance, latitude, elevation, and season. With those inputs, Murphy's model predicted the daily temperature change every 20th sol of our mission. "After we landed, we updated inputs," Crisp noted. "We landed in a place in Gusev Crater not like averages we used before. We are on a darker surface which absorbs more sunlight and get hotter during the day, and increased the atmospheric dust abundance."
Spirit has to survive "an incredibly large swing" in temperature range each day, Crisp said. "Right now, in this early stage of our mission, maximum temperatures hit about -10 Celsius or +15 Fahrenheit -- which corresponds to Minneapolis' low for tonight. The minimum is hitting about -75 C or -100 F at around 6 a.m., Mars time - [which] corresponds to an exceptionally cold night at the South Pole."
As the mission continues, the season in the southern hemisphere will move from summer into autumn, when the low temperatures will "dip a low of -123 F, which is approaching the coldest Antarctic temperatures measured on the Earth," she added.
While there are no temperature sensors on Spirit that directly measure the atmospheric temperature, the models are predicting "quite closely what the temperature sensors on the equipment on the rover, are indicating within 5 degrees C.
Spirit landed on Mars January 3 after a seven-month journey. Its mission is to spend the next three months exploring rocks and soil for clues about whether the past environment in Gusev Crater was ever watery and suitable to sustain life. By virtually every account, that search, so far, is going "extremely well."
The Mini-TES -- the miniature thermal emission spectrometer, which records the thermal spectra of various rocks and soils to determine the types and amounts of minerals that they contain -- has already returned evidence of carbonates and hydrated minerals, which on Earth are usually produced in long-standing bodies of water. The complete 360-degree Mini-TES image is expected to be presented tomorrow or the day after.
Meanwhile, Spirit's twin, Opportunity, is still on target to touchdown on Mars January 24 PST (January 25 Universal Time and EST) to begin a similar geological examination of a site on a vast plain called Meridiani Planum, located on the opposite side of the planet from Gusev Crater.