No one is giving up hope for Spirit. Not Yet. And neither should you.
It’s too soon to turn out the lights. Indeed NASA is stepping up operational efforts to contact the plucky rover – More communications commands; more listening time; more frequencies. Spirit last communicated with mission controllers back on Earth on March 22, 2010. The rover entered hibernation mode – some nine months ago – as the available sunlight to power the life giving solar panels was diminishing. NASA hopes to reawaken Spirit from a long slumber and reignite her breakthrough campaign of exploration and discovery from a scientific goldmine on the surface of the red planet.
“The sun is still rising on Mars,” says Ray Arvidson in an interview from Washington University in St. Louis. Arvidson is the deputy principal investigator for the Spirit and Opportunity rovers.
“We will keep listening for many months if necessary,” Steve Squyres informed me. Squyres is the Principal Scientific Investigator for the Mars Exploration Rover mission.
By the time of the last dispatch from Mars, Spirit had lasted for nearly six years of bonus mission time – during the extended mission phase – light years beyond the 3 month “warranty” proclaimed by NASA as the mission began back in January 2004.
At Spirit’s location in the southern hemisphere of Mars, Southern Summer has not yet arrived. Right now it’s mid Southern Spring and daylight hours are increasing. And Summer doesn’t even start until mid-March 2011. The question is whether Spirit’s unheated electronics components have endured the extremely harsh and frigidly cold conditions of her 4th winter on Mars – her coldest ever. At about -100 C … Imagine Antarctica !
“The amount of solar energy available for Spirit is still increasing every day for the next few months,” said Mars Exploration Rover Project Manager John Callas of NASA’s Jet Propulsion Laboratory (JPL) , Pasadena, Calif. “As long as that’s the case, we will do all we can to increase the chances of hearing from the rover again.”
“We’re stepping up our efforts to contact Spirit — doubling down on her, as it were,” tweeted JPL mars rover driver Scott Maxwell.
And all those negative stories you may have read about Spirit being “Still Stuck” … well they totally missed the point.
In the final Sols, or Martian days, before falling silent in March 2010, there was dramatic movement by Spirit. “During the last 9 drives, Spirit actually moved 34 cm. That’s pretty good for a stationary rover,” Arvidson said.
This movement came despite the loss of two of the rover’s six wheels and after many months of methodical testing in the “Mars sand box”. Engineers at JPL devised and tested numerous strategies in attempting to extricate Spirit from the sand trap of soft soil in which she became mired.
Because of the declining sun and available power, Spirit basically just ran out of time to try and completely escape from the sand trap. This left it unable to obtain a favorable tilt for solar energy during the rover’s fourth Martian winter, which began last May.
Many members of the rover team are hopeful that they can indeed “Free Spirit” if she awakens from her current hibernation mode.
“I have no idea whether we’ll hear from Spirit again or not… there’s simply no way to predict it,” Squyres told me. “We will keep listening for many months. All we can do is listen”
Even if we never hear from Spirit again, she has accomplished a remarkable series of scientific breakthroughs, far beyond the wildest dreams of the science and engineering teams that built and operate the twins.
Both rovers have made important discoveries about wet environments on ancient Mars that may have been favorable for supporting microbial life.
Spirit discovered a rock that contained high levels of carbonates, minerals that form in neutral watery conditions that are far more conducive to the formation of life than the acidic watery conditions reported earlier in the mission.
Although Spirit has been stalled at a place called ‘Troy’ since April 2009. she made a significant science discovery at that exact spot. Spirit examined the soil in great detail and found key evidence that water, perhaps as snow melt, trickled into the subsurface fairly recently and on a continuing basis.
While driving on the western edge of an eroded over volcanic feature named ‘Home Plate’, she unknowingly broke through a hard surface crust (perhaps 1 cm thick) and sank into hidden soft sand beneath. At ‘Troy’, Spirit discovered that the crust was comprised of water related sulfate materials and therefore found evidence for the past flow of liquid water on the surface of Mars – a great science discovery!
After mid-March, prospects for reviving Spirit would begin to drop, say NASA officials. Communication strategies would change based on reasoning that Spirit’s silence is due to factors beyond just a low-power condition. Mission-ending damage from the cold experienced by Spirit in the past Martian winter is a real possibility.
Spirit's panoramic camera (Pancam) took the component images during the period from the 2,163rd to 2,177th Martian days, or sols, of Spirit's mission on Mars (Feb. 2 to Feb. 16, 2010). The turret at the end of the rover's arm appears in two places because of movement during that period. Insets in the upper left and lower right corners of the frame show magnified views of the nearby inscribed rectangles within the mosaic. The patch of ground within each rectangle is about 25 centimeters (10 inches) across. The top inset and upper portion of the mosaic include targets within soil layers exposed by the action of Spirit's wheels in April 2009 and examined in detail with instruments on Spirit's arm during the five subsequent months.
Olive pit and Olive leaf are two of the analyzed targets. The investigations determined that, under a thin covering of windblown sand and dust, relatively insoluble minerals are concentrated near the surface and more-soluble ferric sulfates have higher concentrations below that layer. This pattern suggests water has moved downward through the soil, dissolving and carrying the ferric sulfates. The brightness and color of the freshly disturbed soil seen in the center area of the mosaic indicates the this formerly hidden material is sulfate-rich. Before Spirit drove into this patch, the surface looked like the undisturbed ground highlighted in the lower-right inset. Flecks of red material in the surface layer resemble the appearance of the surface layer at other locations where Spirit's wheels have exposed high-sulfate, bright soils. Image Credit: NASA/JPL-Caltech/Cornell University
Spirit entered a low-power fault mode in March 2010 with minimal activity except charging and heating the batteries and keeping its clock running. With most heaters shut off, Spirit’s internal temperatures dipped lower than ever before on Mars. That stress could have caused damage, such as impaired electrical connections, that would prevent reawakening or, even if Spirit returns to operation, would reduce its capabilities.
“Components within the rover electronic module (REM) inside the rover’s warm electronic box (WEB) are experiencing record low temperatures,” said Doug McCuistion, the director of Mars Exploration at NASA Headquarters in Washington, DC, in an interview about Spirit’s predicament. “The expectation is for the REM hardware to reach -55C at the coldest part of the winter. We have tested the REM down to -55C”.
NASA’s Deep Space Network of antennas in California, Spain and Australia has been listening for Spirit daily in coordination with the spacecraft orbiting Mars; Mars Odyssey and Mars Reconnaissance Orbiter. In X-band, the DSN listens for Spirit during one pass each day. The rover team has also been sending commands to elicit a response from the rover even if the rover has lost track of time.
Now, the monitoring is being increased. Additional listening periods include times when Spirit might mistake a signal from NASA’s Mars Reconnaissance Orbiter as a signal from Earth and respond to such a signal. Commands for a beep from Spirit will be sent at additional times to cover a wider range of times-of-day on Mars when Spirit might awaken.
“DSN does an average of 4 “sweep & beep” commands in each day’s pass,” according to JPL spokesman Guy Webster. Also, NASA is listening on a wider range of frequencies to cover more possibilities of temperature effects on Spirit’s radio systems
Opportunity is still blazing a trail of discovery on the opposite side of Mars. She is currently exploring the stadium sized Santa Maria Carter which holds deposits of water bearing minerals that will further elucidate the potential habitability on the red planet.