Full panorama of Spirit's location in Bonestell. Image Credit: NASA/JPL/Cornell University/New Mexico Museum of Natural History and Science
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What were you doing five years ago today? I remember trying to watch NASA TV on my computer in an effort to monitor the status of the Spirit rover that was on its way to land in Gusev Crater on Mars. The feed kept cutting out, and I know it was way behind what was happening in real time at the Jet Propulsion Laboratory. The scientists and engineers there were certainly more anxious than I, but even I had butterflies in my stomach. During the entry and landing, the spacecraft with Spirit aboard maintained radio contact with flight controllers at JPL through a series of tones designed to transmit the status of the lander. The flight team was even able to detect that the lander was bouncing on the surface of Mars, secure in the inflated airbags. But the tones suddenly stopped and there was no signal from the lander for several minutes. The flight control room erupted when the spacecraft sent the signal that it was sitting safely on the Red Planet.
“There was a lot of jumping, hugging and even a few tears of relief here at JPL,” said Chris Potts, who was the MER Deputy Navigation Team Chief back in 2004. “There were definitely some tense moments when we lost the signal after confirmation of bouncing on the surface. Mars just wanted us to wait a bit longer.” The wait was definitely worth it, and now five years later, Spirit and her twin rover Opportunity are still working hard on Mars’ surface. That fact is truly cause for celebration, and there are a few ways you can join in celebrating…
Another way to celebrate is to check out Scott Maxwell’s blog, “Mars and Me.” Tonight (Saturday) he is going to start making public his “diary” of the past five years, “The diary of a Mars rover driver, I suppose you could say,” Scott writes in his blog. “I’ve decided to make them public now, as a thank-you to everyone who’s followed the mission for so long, everyone who’s dreamed of being part of it. This is what it was like for one person who was, and still is, part of that mission. This is what it was like to be one person living a small part of a grand, historic adventure.” Spirit on top of Husband Hill. Credit: NASA/JPL/Dan Maas
Still another way to celebrate is to listen to Emily Lakdawalla on the Jan. 3rd 365 Days of Astronomy Podcast talk about Spirit’s five years on Mars. The transcript is also available on the site if you’d rather read it.
Also, the image at the top of this article is a full 360-degree panorama from Spirit’s panoramic camera (Pancam). Click on the image to get the full resolution, and to read the notations which indicate locations for several events of the first five Earth years since Spirit landed inside Gusev Crater.
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The HiRISE Camera on board the Mars Reconnaissance Orbiter is keeping an eye on the Phoenix lander, and took the above image of the landing site on Dec. 21, 2008. Phoenix, its heatshield, parachute and backshell are still visible on the Martian arctic plains, providing evidence that the spacecraft hasn’t been covered with ice as of yet. Via the HiRISE Blog, scientists say the conditions are hazy and dark because northern winter summer is turning to autumn on Mars. They will keep imaging the site as long as there is enough light to see the lander. Compare this image to previous photos of the Phoenix site, below.
Phoenix and accoutrements from May 2008. Credit: NASA/JPL/UA
This color image was taken just after Phoenix landed in late May 2008. Insets show the backshell, parachute and heatshield. Phoenix site July 08. Credit: NASA/JPL/UA
In these images, top one taken in July of 2008, and bottom taken in October 2008, you can compare the lighting conditions between late summer and early fall, and now winter (first image) in the northern arctic regions on Mars. Phoenix September 08. Credit: NASA/JPL/UA
Source: HiRISE Blog, HiRISE site
Detail from a panorama taken by the Mars Exploration Rover Spirit on sol 1,366-1,369 (November 6-9, 2007). Credit: NASA / JPL / Cornell
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Some urban legends just won’t die, and sometimes, unfortunately, they are given new life. We’ve already discussed and dismissed the rock on Mars that looks like a Bigfoot – a teeny, tiny little Bigfoot (Jan. 25, 2008). And now it’s back. And it’s completely ridiculous. Amazingly, this guy thinks a publication like National Geographic will take him seriously. Here’s an excerpt from the press release:
“A lawyer in the United States has written the National Geographic Society, asking it to publish in National Geographic his discovery that a photograph taken and beamed back to Earth by NASA’s Mars Rover Spirit contains evidence of life on Mars. In his letter, Andrew D. Basiago, 47, wrote that his analysis of the NASA photograph of the Red Planet captioned PIA10214 has revealed images of human and animal life forms, as well as statues and other structures built by advanced, intelligent beings. “This image is the most significant photograph ever taken by human beings from Earth,” Basiago wrote.
If you take the time to download and look at this “expose” you’ll see what Basiago does is take a large panoramic image from the Spirit rover (the original large panorama can be found here) which is a very high resolution image, and crop out small portions and zoom in so incredibly close that the images become blurry. He then claims these blurry images of rocks on Mars are things like humanoids, animals, statues and other objects.
For example, in this image, this is what Basiago claims he sees:
“Throughout the photograph, the beings with bald, bulbous heads can be seen interacting with a variety of species. On a hillside beneath the mountain ridge in the far upper right quadrant, two of them sit in the Lotus position surrounded by animal species which resemble the penguin and ibis-like figures found in Egyptian hieroglyphics.”
Seriously?
Or this one: Blown up small piece of West Valley Panorama
“At the back of The Rock Garden is a large statue or skeleton of a humanoid with a pointy head and large, elephantine ears (right). His skull, arms, and hands are evident on the surface. He is reaching out from the depths of Mars with his hands. This skull may be the fossilized head of a giant primate in Martian history or simply the statue of a demon.”
This entire 41-page treatise is chock full of blurry, blown-up and stretched crops of incredibly small pieces of the large image, complete with incredible tales of humanoids in body suits and plesiosaurs co-existing together, along with features like Egyptian-like hieroglyphics and a sarcophagus.
The “Bigfoot on Mars” rock is actually just a few inches high and a few yards from the camera. The other rocks are in about the same location, although some are farther, some closer – it’s a big panorama. The thing about the color images from Mars is that each color image consists of three photos, taken with different filters to create the color. The three images are taken at different times, which means if something is moving, the image won’t be crisp and clear, as the original large panoramic image is. Emily Lakdawalla explains it very well at the Planetary Blog. She explains that Spirit took several images of the same location, showing the same rock over three different days, and it never moved.
Here’s all the pictures Emily found and put together:
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In preparation of celebrating Spirit and Opportunity’s fifth anniversary on Mars in January, we’ve been talking with rover driver Scott Maxwell, getting updates on the two Mars Exploration Rovers and learning about what it really is like to drive the rovers. Today, Scott will share some of the highlights of the past five years, and his outlook for the future. But first, in the latest updates from Scott via Twitter, he says Spirit tried to back-up off of ‘Home Plate’ but encountered quite a bit of slippage. It looks like she’ll probably end up driving forward and taking the long way around the low plateau to the next target objects, a hill called Von Braun, and a crater-like feature nearby called Goddard. Meanwhile, Opportunity is studying “cobbles” or loose rocks at a region called Santorini, where she has been stationed during solar conjunction. Now that radio transmissions are improving, Oppy will start receiving commands from the rover drivers to hit the road again. The image above is a panoramic image of Santorini, put together by James Canvin at his website, Martian Vistas.
Scott has actually been with the MER mission for longer than just the five years since the rovers landed. He joined the team early on, about three-and-a-half years before the rovers launched. He was part of the development team, helping to write the software used to drive the rovers. Back then, did he ever fathom the rovers would last this long?
How to Drive a Mars Rover, Part 1 How to Drive a Mars Rover, Part 2
“I think back, to that time, and we did all that work where we sat in our cubicles, had meetings and argued with each other about the best way to program the software,” said Scott. “We slaved away working on the mission, never knowing if the mission would succeed or not. We did all that work just for the chance, the hope, that the rovers would be working on Mars for three months. And it was worth it.”
The rover planners include Rich Morris, Scott Maxwell, Sharon Laubach, Joseph Carsten, John Wright and Brian Cooper; and (front row) Tara Estlin, Paolo Bellutta and Ashley Stroupe. Credit: PBS
“And then to do all that work and have the rovers on Mars for five years, it’s like you’re playing a slot machine and you put in your quarter and pull the lever, and not only do a few quarters come out, they keep coming and coming and coming, and it fills up your cup, and overflows. That’s what it’s like to work on this mission.”
OK, Scott, now we want to know the highlights for you from the past five years. Certainly there’s at least one or two memorable moments!
“Certainly for me, there are two things I think of,” Scott said. “One is the first time I ever drove the rover. There was the period early on where we lost contact with Spirit. But then we were able to recover her. But that was a month into the mission where we thought it was only going to last three months, and it delayed the time until I got my first chance to drive her.”
“I still remember the day. We planned and planned and rehearsed the drive. I checked over the sequence a million times before sending it. Then I went home and I should have gone to sleep, but I couldn’t. I just laid there in my bed and stared at the ceiling, and couldn’t get past the thought that right then, at that moment, there was a robot on another planet, doing what I had told it to do. It was just an awesome feeling to imagine that, and that feeling has never left me. I still feel like that every time I drive the rover.”
Scott says it’s an incredible feeling to go outside and look up and see Mars in the sky, and on that red dot way out there is an object, placed there by humans, and humans are telling it what to do. “And I’m one of the people doing that. It’s an absolutely amazing feeling. I feel that way all the time.” Scott Maxwell, rover driver. Image courtesy Scott Maxwell
Its obvious Scott has a soft spot in his heart for Spirit, as another memorable aspect of the mission involves her, too. Scott tells the story so well and with such passion, I’ll just let him go:
“The other thing I always think about is that Spirit travels the 300 million miles to Mars, she gets to Mars, drives off the lander, and she’s gone all that way with the hope of finding evidence of past liquid water on Mars,” Scott said. “But instead, when she drives around, there’s nothing: just lava as far as the eye can see. She drives around the area and looks at rocks, and then drives over to Bonnevillle crater, which is her best chance of finding evidence of liquid water, thinking maybe if she goes down far enough into this crater there will be something there, but there’s nothing.”
“But way off in the east, there are a range of hills, the Columbia Hills, and (principal investigator) Steve Squyres says clearly the hills may be too far for us to get to, but maybe we can get some images that can tell us something. But Spirit takes off for those hills anyway, even though they are too far away, and never gives up and gets there; she actually makes it all the way to the bottom of the hills.”
“And then,” Scott continued, “she’s at the bottom of the hill, looking up at them, and it’s now twice as long as she should have survived and she has driven three times as far as she was supposed to be able to drive, and she’s tired and her wheels are sore, now is when the real challenge will begin. Now she won’t just be driving over flat terrain, like she was meant to drive on. She’s going to have to climb the hill, which is taller than the Statue of Liberty, and everyone thinks it’s way too tall for this poor little rover to climb. But she does it anyway.”
“She starts climbing up the hill and there are times when she can’t make any progress, so we have to turn her around and give up some of the altitude she’s won and go back and find another path, but she never gives up and goes all the way to the top of that hill that was just impossibly far away when she started.” A special effect image of Spirit sitting on Husband Hill. Credit: NASA/JPL/Cornell. Rover model by Dan Maas
“When we came into work that day and we saw that image of Spirit standing on top of Husband Hill with the beautiful panorama of the world around her –she stood there for a long time and took the images of the area around her — to me, that’s one of the achievements, not just of this mission, but of engineering excellence in our whole civilization, to be able to do that. To be able to go so far and do so many impossible things, that image just says all of that for me. I know what it took to get there and be able to take that image, and I feel the pride of being part of the team that made it happen. It is just an amazing experience.”
As incredible as the MER mission has been, we all know the rovers won’t last forever. Someday – and we don’t know when – the rovers will eventually quit working. It’s hard to think about life without the rovers, but has Scott given any thought to what mission he would like to work on next?
“It’s all downhill from here!” Scott laughed. “But, really there’s a lot of cool and exciting stuff going on at JPL. We’ve got another rover we’re working on, the Mars Science Laboratory, and I’ve been working on that. I’m also involved with ATHLETE, which is a 12-ft. tall six legged robot spider on roller skates that we are going to send to the moon. There’s always so much like that going on here at JPL, it’s just like being an engineer in Disneyland. You come to work and say, ‘What cool stuff can I work on today?’ It’s just awesome, and there’s just no end to it.”
Scott says he has nothing against orbiter missions, but to be honest they’re not top on his list. “I’m not putting them down,” he said, “but orbiters don’t really float my boat. I kind of get into rovers, I kind of relate to them, in a way. But you look at a mission like Cassini and it’s amazing! Cassini is finding liquid water spewing out of Enceladus, and dropping a probe onto Titan and getting the first view beneath the thick clouds that cover that moon! It’s just amazing stuff. So even though orbiters aren’t my thing, I might end up on one of them, too, you never know.”
Scott has definitely shown his worth with the rovers, so, even though the MSL launch has slipped to 2011, the rover fans out there are secretly hoping Scott will have a place on the MSL team when the time comes. Spirit heading off into the sunset. Special effects image by NASA/JPL/Cornell
But in the meantime, Spirit and Opportunity, the Energizer Bunnies of Mars exploration keep going and roving, and sending back loads of data and images.
Dust storm on Mars. Image credits: NASA/JPL-Caltech/MSSS
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What an incredible image of a storm on Mars! The Mars Reconnaissance Orbiter’s main assignment is to study the surface of the Red Planet, looking for clues about the history of water on Mars. But while photographing, analyzing and mapping, it also spends time each day pursuing intense weather on Mars. Sometimes, MRO is able to capture a storm in action, as in the above image of a dust front rising from a network of canyons. Often, the storms are spirals like giant tornadoes on Earth, sometimes forming huge fronts of churning dust like the “dust bowl” of the 1930s in the US. While we sometimes think of Mars as an almost “dead” world, there’s a lot of action going on in the atmosphere, and MRO is always searching for the Perfect Storm!
Dust storms on Mars are catalysts for cloud formation. The storms lift dust particles high into the atmosphere, and the particles serve as seeds for water-ice cloud formation. Water ice condenses onto the dust particles to form wispy, white clouds. Daily variations in Mars’ atmosphere are quite large, in part because there is no ocean, which serves as large heat storage capacity on the surface. The ground warms up quickly during the day and cools off equally as quick at night. Daily temperature variations of 100 C (180 F) are common, and that cycle of heating and cooling is reflected in atmospheric variations. “That energy propagates up, and when integrated to the high altitudes, it can make a big difference from day to night in the densities that we saw at a given altitude,” said MRO Project Scientist Richard Zurek. Storms as seen by the Mars Color Imager. Image credits: NASA/JPL-Caltech/MSSS
These images show whirlwinds on top of volcanoes. Thin veils of icy clouds dissipate into the atmosphere above the dust plumes. The orbiter has discovered that smaller storms on Mars can feed into larger storms. Dust devils seen by the HiRISE camera. Credit: NASA/JPL/University of Arizona
And of course, dust devils on Mars are a common occurrence in several areas, as they have been photographed by both the Mars Exploration Rovers, as well as Phoenix.
Scott Maxwell, using his 3-D simulation software. Courtesy Scott Maxwell
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The Mars Exploration Rovers have been traversing the surface of the Red Planet for almost five years now. But how exactly are the two rovers, Spirit and Opportunity, “driven” from Earth, about 150 million km away? Many of us might have visions of joysticks, similar to what are used for remote control toys, but it’s not like that at all. However, being a “Rover Driver” is one job where having experience with video games and simulation software looks good your resume! Scott Maxwell is one of fourteen rover drivers, or planners as they are also called, who last week gave us an update on Spirit and Opportunity’s status. Today, Scott provides the details of how to drive a Mars rover.
“The way we wished it would work,” said Scott in a phone interview from JPL, “is if we could have a joystick where if we pushed forward on the joystick the rover would go forward, or push back and the rover would stop. But, with lag time delays in the radio signals, you would push forward on the joystick and 10 minutes later the rover would get the signal to go. But on Earth, you won’t know if it worked for another 10 minutes after that because of the time it takes for the signal to get back to you.”
This would create a nightmare in logistics, planning and operations, because the drivers can’t “see” what the rover is doing in real time. So instead, the rover drivers work the Martian nightshift. Recent view from Opportunity's hazard camera. Credit: NASA/JPL/Cornell
“We take advantage that our solar powered rovers have to shut down for the night,” said Scott. “So as the sun is going down in the Martian sky, the rover is commanded to take pictures of the world around them and send it before they go to sleep. When we get that data back on Earth, we go to work. We take all the images and put them into a simulation. We have a 3-D simulation world — kind of like a video game — on our computers. Then, we have a simulated rover that we put down in that 3-D world and we drive that rover around instead.”
So in that 3-D world, the rover drivers can test every possibility, make all the mistakes (tip the rover, get stuck, drive off a precipice, crash into a big rock) and perfect the driving sequence while the real rovers are dozing securely and peacefully. This certainly has helped with the long life the rovers have led, as in five years the rover drivers have safely and successfully guided the rovers to drive in and out of craters, climb a challenging hill, and put on more mileage than anyone ever thought possible. The biggest driving calamity has been getting stuck in a sand dune, but now the driving team has a few tricks up their sleeves to avoid that (see Part 1).
So then, when the drivers perfect the commands inside the simulation and hone the exact sequence of movements for the rover, they upload those commands and send it to the real rover. Then as the sun is coming up on Mars, the rover wakes up, receives a communications uplink from Earth, processes the commands and it goes to work while the rover drivers go to sleep. “At the end of the rover’s day, it sends us more pictures and data, and we start the cycle all over again,” Scott said. Rover test bed. Credit: JPL
If there’s a particularly difficult situation, such as how much tilt can the rover withstand without tipping over, a test rover can go through the same sequences in a simulated Mars environment out in JPL’s Mars Yard.
Back in 2004 during the “prime mission,” the first three months of the mission (the original length of time the rovers were slated to last) everyone who worked with MER lived on Mars time. Since the two rovers are on opposite sides of the planet, that meant operations going on 24 hours a day. And since a Mars day is 40 minutes longer than Earth’s day, that meant a perpetually shifting sleep/wake cycle, a difficult situation where your body continually feels “jet-lagged.” But now that the mission has been ongoing for such a long time, the planners operate in a more Earth-normal mode and even take some weekends off. But still, a planner’s eight- hour shift can start anywhere from 6:00 a.m. to noon.
So what’s an average drive for the rovers? “It varies widely,” Scott said, “but an average drive is in the neighborhood of a few meters.” Right now Spirit is struggling her way up the side of “Home Plate,” a low plateau, which for a rover is a steep hill. The crumbly soil gives out beneath her wheels as she makes the climb, making it difficult to drive father than a few centimeters in a day. Plus, Spirit is dealing with low power levels from dust-covered solar panels, providing limited energy for any big drives. Just after a recent dust storm, Spirit’s solar panels were producing only 89 watt hours, which is about the energy needed to run a small light bulb for an hour and half. Spirit's dusty solar panels. Credit: NASA/JP
But Opportunity’s power levels are much better, and she recently had drives as long as 216 meters, as she puts the pedal to the metal in an attempt to reach Endeavour Crater, about 12 km away.
Some of the rover drivers work mainly with one rover (Steve Squyres has said it’s easy to get attached to one rover or the other, depending which one you’re working with) but Scott goes back and forth between the two. “That’s in part because I’m a team lead, and part because I’m the kind of person who wants to run around and be part of everything all the time!” he said. When we talked with Scott last week, he was working with Spirit, and thought that this week he will probably do a drive or two with Opportunity.
Currently Spirit’s total odometry is at about 7,530 meters (over 4.6 miles), while Opportunity’s odometer reads almost 14,000 meters (about 9 miles).
Carbonates appear in green in this area about 20 km (12 miles) wide on Mars. NASA/JPL/JHUAPL/MSSS/Brown University
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Scientists from the Mars Reconnaissance Orbiter have made a major discovery about the history of water on Mars. The CRISM instrument, the Compact Reconnaissance Imaging Spectrometer for Mars, on board NASA’s Mars Reconnaissance Orbiter has found carbonates, a long-sought-after mineral, embedded in bedrock on the Martian surface. The Phoenix Mars Lander also discovered carbonates in soil samples, which was a surprise and MRO has observed carbonates in windblown dust from orbit. However, the dust and soil could be mixtures from many areas, so the carbonates’ origins have been unclear. The latest observations indicate carbonates may have formed over extended periods on early Mars. Additionally the new findings indicate that Mars had neutral to alkaline water when the minerals formed at these locations more than 3.6 billion years ago, and not the acidic soil that appears to dominate the planet today. This means that different types of watery environments have existed on Mars. The greater the variety of wet environments, the greater the chances one or more of them may have supported life.
“We’re excited to have finally found carbonate minerals because they provide more detail about conditions during specific periods of Mars’ history,” said Scott Murchie, principal investigator for the instrument at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.
Carbonate rocks are created when water and carbon dioxide interact with calcium, iron or magnesium in volcanic rocks. Carbon dioxide from the atmosphere becomes trapped within the rocks. If all of the carbon dioxide locked in Earth’s carbonates were released, our atmosphere would be thicker than that of Venus. Some researchers believe that a thick, carbon dioxide-rich atmosphere kept ancient Mars warm and kept water liquid on its surface long enough to have carved the valley systems observed today.
“The carbonates that CRISM has observed are regional rather than global in nature, and therefore, are too limited to account for enough carbon dioxide to form a thick atmosphere,” said Bethany Ehlmann, lead author of the article and a spectrometer team member from Brown University, Providence, R.I.
On Earth, carbonates include limestone and chalk, which dissolve quickly in acid.
“Although we have not found the types of carbonate deposits which might have trapped an ancient atmosphere,” Ehlmann said, “we have found evidence that not all of Mars experienced an intense, acidic weathering environment 3.5 billion years ago, as has been proposed. We’ve found at least one region that was potentially more hospitable to life.” Possible carbonates in Nilli Fossae. Credit: NASA/JPL/University of Arizona
The researchers report clearly defined carbonate exposures in bedrock layers surrounding the 1,489-kilometer-diameter (925-mile) Isidis impact basin, which formed more than 3.6 billion years ago. The best-exposed rocks occur along a trough system called Nili Fossae, which is 666 kilometers (414 miles) long, at the edge of the basin. The region has rocks enriched in olivine, a mineral that can react with water to form carbonate.
“This discovery of carbonates in an intact rock layer, in contact with clays, is an example of how joint observations by CRISM and the telescopic cameras on the Mars Reconnaissance Orbiter are revealing details of distinct environments on Mars,” said Sue Smrekar, deputy project scientist for the orbiter at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
The findings will appear in the Dec. 19 issue of Science magazine and were announced Thursday at a briefing at the American Geophysical Union’s Fall Meeting in San Francisco.
Rover Driver Scott Maxwell with a model of MER. Photo courtesy Scott Maxwell
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In January of 2004, NASA’s twin robot geologists, the Mars Exploration Rovers Spirit and Opportunity, landed on the Red Planet. During those nearly five years, the rovers have returned hundreds of thousands of images and enough data to keep scientists busy for decades. But almost nine years ago, Scott Maxwell started working on developing software and techniques for driving the rovers around on Mars surface. Today he’s the Mars Rover Driver Team Lead for MER at JPL, and he says that every day of working on this mission has been incredible. “It’s been an amazing experience,” he said, “and I like to say it’s the best job on two planets.” To celebrate the upcoming fifth anniversary of the rovers on Mars, Universe Today caught up with Scott to get an update on the current status of the two rovers, to find out what the five-year MER mission has been like for a rover driver, and to ask the pressing question, just how do you drive a rover from 150 million kilometers away?
Both rovers have been inactive recently because of solar conjunction, where the sun is between Earth and Mars, which makes communications difficult because the amount of radio noise generated by the Sun. So, when I talked to Scott on Wednesday of this week he was just working on the commands that would be sent to Spirit for the first drive she has taken since several weeks ago. So how is Spirit doing these days?
“Spirit is struggling valiantly to climb up the north face of Home Plate,” Scott said. “As you know, we’ve just come out of solar conjunction, and so we’re picking up where we left off on Spirit’s climb up the face. Her solar array energy levels are not as good as they were before the mini-dust storm we had before the conjunction, so that’s obviously a cause for concern. It’s unfortunate because that means we have less energy for driving. But she’s still alive and that’s a lot better than what we thought she’d be five years into the mission.” Home Plate is the raised plateau. Spirit is the dark spot at the 1 o'clock position. Image: NASA/JPL/University of Arizona
Home Plate is a low plateau about 80 meters (260 feet) in diameter. Spirit spent the Martian winter parked on the north side of the plateau with her solar panels slanted towards the low sun in order to stay alive. But Spirit’s solar arrays are severely dust-covered, decreasing the amount of power available for science activities and driving. But the scientists and engineers haven’t given up on Spirit, and still have big plans for her.
“Our longer term goal is to head south from Home Plate to a pair of features called ‘Goddard’ and ‘Von Braun’,” said Scott. “Von Braun is a hill and Goddard is a crater-like feature next to it, and that’s the next area we’d like to explore. As you know, the area around home plate appears to be a region of past hot-springs or volcanic fumarole activity, the kind of place where life might have formed on Earth, so it makes it a particularly exciting place to explore on Mars, as we try to find out more about what was going on here.”
But ‘Goddard’ and ‘Von Braun’ are on the south side of Home Plate and Spirit is on the north side. The easiest route would be to “climb back up on the top of Home Plate and kind of skate across it where the driving is good” Scott said, but if Spirit isn’t able to make the climb, they will drive down the north slope and go around Home Plate the long way. But that might take more time, and time might be getting limited for Spirit. Bonestell panorama, taken by Spirit during her winter stay on the north side of Home Plate. Credit: NASA/JPL/Cornell
So, the shortest way is up and over Home Plate. But Spirit has a bum right front wheel, and is trying to climb up some difficult terrain. “Imagine you’re in the desert, climbing up a sand dune, but every step you take the sand crumbles out from beneath you,” said Scott. “That’s what Spirit is experiencing. So even though we’re commanding the wheels to go several meters, she might only make a few centimeters of progress in a sol (Martian Day).”
But the driving team will keep trying, as ‘Von Braun’ and ‘Goddard’ are of interest to the science team.
Opportunity, on the other hand, is in very different driving conditions. “Right now she’s basically on a parking lot, with only a couple of speed bumps every once in awhile,” Scott said. “Opportunity can drive 100 meters a sol, like the length of a football field every day, without breaking a sweat. We recently had a nearly record-setting drive, with Opportunity where we drove nearly 216 meters in one day,” Scott said proudly. “So that’s our silver medal drive, our second longest drive ever with either of the rovers.” (The longest drive was 220 meters in one day.)
One thing Opportunity does have to watch out for is sand dunes in the region. In 2005, Opportunity became stuck in one of those dunes, and it took the rover driving team over a month to figure out how to maneuver Opportunity out of the sand trap, called Purgatory Dune. In honor of the difficulties and lessons learned from getting stuck, all the potential sand traps in the region are called “Purgatoids.”
“Opportunity is in a region where Purgatiods are all around her.” Scott said. “But the good news is that we have better data now, than we did when we first encountered these features.” The MER team now has the benefit of the Mars Reconnaissance Orbiter’s HiRISE Camera in orbit around Mars, looking down at — if not watching over – the rovers and their activities. “So we have the data and images from HiRISE, and we think we have identified a way to pick out these Purgatoids from orbit.” Scott said. “So we take the images from MRO, and use them as part of our path planning for Opportunity every day, and also for our longer scale path planning. On top of that we have other measures we have adopted after that first Purgatory incident, where the rover stops every once in awhile and ‘checks’ itself, gauging whether it is actually moving or if it is stuck and the wheels are just spinning. So even if we get into a Purgatoid, we’ll be able to catch it before too long and have the chance to get ourselves out before we dig in too far.”
But so far, with the new technique of being able to identify Purgatoids from orbit, Opportunity hasn’t run into a single one. Opportunity's traverse map through Sol 1716 As of sol 1707 (Nov. 11, 2008), Opportunity's total odometry was 13,493.85 meters (8.38 miles).
“It makes us happy to put the pedal to the metal and just drive,” Scott said, “It’s a lot of fun.”
Opportunity is “putting the hammer down” to reach a crater about 12 kilometers (7 miles) away called Endeavour. The huge crater is 22 kilometers (13.7 miles) across, and scientists expect to see a much deeper stack of rock layers than Opportunity saw while she was in Victoria Crater the past two years. The 12 km driving distance would match the total distance it has traveled from 2004 to mid-2008. Even at the 100-meter plus pace each sol, the journey could take two years.
But Scott Maxwell and the 13 other rover drivers working on the MER mission are up for the challenge.
The Phoenix lander dug this trench in the Mars artic region. Image NASA/JPL-Caltech/University of Arizona/Texas A&M University
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Scientists from the Phoenix Mars Lander mission say the lander uncovered clues that the Martian arctic soil has been warmer and wetter in the past, and right now Mars may just be in a dry cycle. The biggest clue is the “clumpiness” of the soil in the Mars arctic region that Phoenix encountered, making it difficult for the lander to dump samples into the “ovens” that analyzed the chemistry of the soil. While currently the soil is cold and dry, when long-term climate cycles make the site warmer, the soil may get moist enough to modify the chemistry, producing effects that persist through the colder times. “We have snowfall from the clouds and frost at the surface, with ice just a few inches below, and dry soil in between,” said Phoenix Principal Investigator Peter Smith of the University of Arizona , Tucson . “During a warmer climate several million years ago, the ice would have been deeper, but frost on the surface could have melted and wet the soil.”
With no large moon like Earth’s to stabilize it, Mars goes through known periodic cycles when its tilt becomes much greater than Earth’s. During those high-tilt periods, the sun rises higher in the sky above the Martian poles than it does now, and the arctic plain where Phoenix worked experiences warmer summers.
“The ice under the soil around Phoenix is not a sealed-off deposit left from some ancient ocean,” said Ray Arvidson of Washington University in St. Louis , lead scientist for the lander’s robotic arm. “It is in equilibrium with the environment, and the environment changes with the obliquity cycles on scales from hundreds of thousands of years to a few million years. There have probably been dozens of times in the past 10 million years when thin films of water were active in the soil, and probably there will be dozens more times in the next 10 million years.”
Cloddy texture of soil scooped up by Phoenix is one clue to effects of water. The mission’s microscopic examination of the soil shows individual particles characteristic of windblown dust and sand, but clods of the soil hold together more cohesively than expected for unaltered dust and sand. Arvidson said, “It’s not strongly cemented. It would break up in your hand, but the cloddiness tells us that something is taking the windblown material and mildly cementing it.”
That cementing effect could result from water molecules adhering to the surfaces of soil particles. Or it could be from water mobilizing and redepositing salts that Phoenix identified in the soil, such as magnesium perchlorate and calcium carbonate.
The Thermal and Electrical Conductivity Probe on Phoenix detected electrical-property changes consistent with accumulation of water molecules on surfaces of soil grains during daily cycles of water vapor moving through the soil, reported Aaron Zent of NASA Ames Research Center, Moffett Field, Calif., lead scientist for that probe.
“There’s exchange between the atmosphere and the subsurface ice,” Zent said. “A film of water molecules accumulates on the surfaces of mineral particles. It’s not enough right now to transform the chemistry, but the measurements are providing verification that these molecular films are occurring when you would expect them to, and this gives us more confidence in predicting the way they would behave in other parts of the obliquity cycles.”
Phoenix worked on Mars this year from May 25 until November 2.The Phoenix science team will be analyzing data and running comparison experiments for months to come. Today, they reported on some of their progress at a meeting of the American Geophysical Union in San Francisco.
Scientists have been intrigued and puzzled by light-toned layered deposits on Mars since the Mariner spacecraft flybys in the early 1970s. Known as LTDs (Light Toned Deposits), they are Martian sediments that most closely resemble sediments on Earth and are some of the most mysterious features on Mars. Causes for their origin remain unknown, and different mechanisms, including volcanic processes, have been proposed for their formation. But recently data and images from Mars Express suggest that several LTDs were formed when large amounts of groundwater burst on to the surface. Scientists propose that groundwater had a greater role in shaping the Martian surface than previously believed, and may have sheltered primitive life forms as the planet started drying up.
LTDs were some of the first features seen on Mars, because they showed up even in the black and white images sent back by the first spacecraft to flyby Mars. But they are also some of the least understood features on the Red Planet, and have been highly debated. These deposits occur on a large scale in Arabia Terra, Chaotic Terrain and Valles Marineris, close to the Tharsis volcanic bulge.
Now, based on Mars Express data, scientists propose that these sediments are actually younger than originally believed. Angelo Rossi and several colleagues report their findings in a paper published in September of this year in Geophysical Research. They have proposed that several LTDs may have been deposited by large-scale springs of groundwater that burst on to the surface, possibly at different times.
Analysis also indicates that ground water had a more wide-ranging and important role in Martian history than previously believed. Hydrated minerals, relatively young in age, have been found in the region.
Given that the deposits are relatively young in age, and associated with water, they may also have sheltered microbial life from the drier and harsher climate in more recent times on Mars, possibly eliminating the need for a stable atmosphere or a permanent water body.
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