Panorama Captures Landing Petal
This image mosaic taken by the panoramic camera onboard the Mars Exploration Rover Spirit shows the rover’s landing site, the Columbia Memorial Station, at Gusev Crater, Mars.
|Base petal of Mars Exploration Rover (MER-A) mission, from which the Spirit rover ‘stood-up’ and drove away from a week and half after touchdown. The larger ‘puffed-out’ airbag to the back right blocked forward egress and potentially could have caught one of the rover’s solar panels. So the rover was turned in place 120 degrees to egress to the forward left in this picture.
The landing petal, or base station for the first week and half on Mars was actually raised about 40 cm above the soil, and rover wheels did not touch dirt until abandoning this petal as ‘debris’. During its multiple bounces (nearly 30 total) on the surface when its airbags were inflated, the rover stood a one-in-four chance of landing in the configuration show, with base-petal down. This configuration can sometimes speed up early communication, by avoiding a flipping motion to right the initial up-and-down location.
This spectacular view may encapsulate Spirit’s entire journey, from lander to its possible final destination toward the east hills. On its way, the rover will travel 250 meters (820 feet) northeast to a large crater approximately 200 meters (660 feet) across, the ridge of which can be seen to the left of this image.
To the right are the east hills, about 3 kilometers (2 miles) away from the lander. The east hills are closest to the Mars Exploration Rover Spirit in comparison to other hill ranges seen on the martian horizon. The top of the east hills are approximately 2 to 3 kilometers (1 to 2 miles) away from the rover’s approximate location.
Early guesses formulated before this exacting work was completed put the hills at about 50 to 100 meters (about 165 to 330 feet) high and between 1 and 2 kilometers (about half a mile to a mile) away. What makes the eastern hills an interesting target is that they may be much older than the rocks and soil in the vicinity of the landing site – perhaps billions of years older. If they are, they would tell a story about a completely different time in the history of Gusev Crater than the nearby rocks and soil.
"We asked the rover engineers to fit a square peg in a round hole," said the Spirit rover mission manager, Jennifer Trosper of NASA JPL. "…the engineering team unfolded that square rover from its triangular landing petal."
|A simulated image of the Mars rover protected by descent-bracing airbag pyramid. Dust was kicked up onto the rover bags, making them ‘instant’ rocks in low resolution images.
For mobility, the Spirit rover first had to pass successfully through its four part ‘stand-up’ routine–a staged series of maneuvers that transform its scientific laboratory on wheels "from a lander to a rover", said Chris Voorhees, one of the JPL mechanical engineers tasked with the stand-up. The wheels and arms of the rover have remained nested underneath its main solar panels for seven months, since it launched from Florida seven months ago. "The tetrahedral landing petal is not a shape that a rover wants to be in," continued Voorhees, "so we have to stand-up in stages. They happen like reverse robotic origami."
"This is one of the most complex deployments ever done", said Voorhees, to get the rover "standing on all sixes. It involves twelve pyrotechnics, nine motors, six structural latches, and two hazard avoidance cameras."
The picture was taken on the 16th martian day, or sol, of the mission (Jan. 18/19, 2004). A portion of Spirit’s solar panels appear in the foreground. Data from the panoramic camera’s green, blue and infrared filters were combined to create this approximate true color image.
NASA’s Eddie Tunstel, Spirit’s mobility engineer, assessed the rover’s overall mobility at Gusev crater, as a "pretty benign site. We might avoid rocks combined with sandy soil, so we don’t lose [wheel] traction, and [avoid] some of the slopes in the far distance. It is pretty wide open where we are," a flat feature of what may eventually prove to be an ancient crater lakebed.
The rover’s landing site at Gusev crater was predicted to have less than eight percent rock coverage, a desired smoothness to ease longer drives. After viewing the panoramic images, scientists have assessed the site to be even more favorable with around three percent. Previous landing sites for Viking and Pathfinder have averaged around six to seven times more rocks than Gusev, with up to twenty percent total coverage and significantly larger varieties.
Flight-team engineers for NASA’s Mars Exploration Rover Mission were encouraged this morning when Spirit sent a simple radio signal acknowledging that the rover had received a transmission from Earth.
However, the team is still trying to diagnose the cause of earlier communications difficulties that have prevented any data being returned from Spirit since early Wednesday.
"We have a very serious situation," said Pete Theisinger of NASA’s Jet Propulsion Laboratory, project manager for Spirit and its twin, Opportunity.
Spirit did send a radio signal via NASA’s Mars Global Surveyor orbiter Wednesday evening, but the transmission did not carry any data. Spirit did not make radio contact with NASA’s Mars Odyssey during a scheduled session two hours later or during another one Thursday morning. It also did not respond to the first two attempts Thursday to elicit an acknowledgment signal with direct communications between Earth and the rover, and it did not send a signal at a time pre-set for doing so when its computer recognizes certain communication problems. The successful attempt to get a response signal came shortly before 9 a.m. Pacific Standard Time.
No single explanation considered so far fits all of the events observed, Theisinger said. When the team tried to replicate the situation in its testing facility at JPL, the testbed rover did not have any trouble communicating. Two of the possibilities under consideration are a corruption of flight software or corruption of computer memory, either of which could leave Spirit’s power supply healthy and allow adequate time for recovering control of the rover.
Engineers will continue efforts to understand the situation in preparation for scheduled communication relay sessions using Mars Global Surveyor at 7:10 p.m. PST and Mars Odyssey at 10:35 PST. Efforts to resume direct communications between Spirit and antennas of NASA’s Deep Space Network will resume after the rover’s expected wake-up at about 3 a.m. PST Friday.
Meanwhile, mission leaders decided to skip an optional trajectory correction maneuver today for Opportunity, the other Mars Exploration Rover. Opportunity is on course to land halfway around Mars from Spirit, in a region called Meridiani Planum, on Jan. 25 (Universal Time and EST; Jan. 24 at 9:05 p.m. PST).