Welcome to the 575th Carnival of Space! The Carnival is a community of space science and astronomy writers and bloggers, who submit their best work each week for your benefit. We have a fantastic roundup today including news from the IAU, so now, on to this week’s worth of stories! Continue reading “Carnival of Space #575”
Martian dust storms are a pretty common occurrence, and generally happen whenever the southern hemisphere is experiencing summer. Though they can begin quite suddenly, these storms typically stay contained to a local area and last only about a few weeks. However, on occasion, Martian dust storms can grow to become global phenomena, covering the entire planet.
One such storm began back in May, starting in the Arabia Terra region and then spreading to become a planet-wide dust storm within a matter of weeks. This storm caused the skies over the Perseverance Valley, where the Opportunity rover is stationed, to become darkened, forcing the rover into hibernation mode. And while no word has been heard from the rover, NASA recently indicated that the dust storm will dissipate in a matter of weeks.
The update was posted by NASA’s Mars Exploration Program, which oversees operations for the Opportunity and Curiosity rovers, as well as NASA’s three Mars orbiters (Mars Odyssey, MRO, and MAVEN) and the Insight lander (which will land on Mars in 109 days). According to NASA, the storm is beginning to end, though it may be weeks or months before the skies are clear enough for Opportunity to exit its hibernation mode.
As noted, dust storms occur on Mars when the southern hemisphere experiences summer, which coincides with the planet being closer to the Sun in its elliptical orbit. Due to increased temperatures, dust particles are lifted higher into the atmosphere, creating more wind. The resulting wind kicks up yet more dust, creating a feedback loop that NASA scientists are still trying to understand.
Since the southern polar region is pointed towards the Sun in the summer, carbon dioxide frozen in the polar cap evaporates. This has the effect of thickening the atmosphere and increasing the surface pressure, which enhances the process by helping suspend dust particles in the air. In some cases, the dust clouds can reach up to 60 km (40 mi) or more in elevation.
Planet-wide dust storms are a relatively rare occurrence on Mars, taking place every three to four Martian years (the equivalent of approximately 6 to 8 Earth years). Such storms have been viewed many times in the past by missions like Mariner 9 (1971), Viking I (1971) and the Mars Global Surveyor (2001). In 2007, a similar storm took place that darkened the skies over where Opportunity was stationed – which led to two weeks of minimal operations and no communications.
While smaller and less intense the storm that took place back in 2007, the current storm intensified to the point where it led to a level of atmospheric opacity that is much worse than the 2007 storm. In effect, the amount of dust in the atmosphere created a state of perpetual night over the rover’s location in Perseverance Valley, which forced the rover’s science team to suspend operations.
This is due to the fact that Opportunity – unlike the Curiosity rover, which runs on nuclear-powered battery – relies on solar panels to keep its batteries charged. But beyond suspending operations, the prolonged dust storm also means that the rover might not be to keep its energy-intensive survival heaters running – which protect its batteries from the extreme cold of Mars’ atmosphere.
Luckily, NASA scientists who have been observing the global event indicated that, as of last Monday (July 23rd), more dust was falling out of the planet’s thin air than was being raised into it. This means that the global weather event has reached its decay phase, where dust-raising events either become confined to smaller areas or stop altogether.
Using its Mars Color Imager (MARCI) and Mars Climate Sounder (MCS), NASA’s Mars Reconnaissance Orbiter (MRO) also noted surface features were beginning to reappear and that temperatures in the middle atmosphere were no longer rising – which indicates less solar heating by dust. The Curiosity rover also noted a decline in dust above its position in the Gale Crater on the other side of the planet.
This is certainly good new for the Opportunity rover, though scientists expect that it will still be a few weeks or months before its solar panels can draw power again and communications can be reestablished. The last time communications took place with the rover was on June 10th, but if there’s one thing the Opportunity rover is known for, it’s endurance!
When the rover first landed on Mars on January 25th, 2004, its mission was only expected to last ninety Martian days (sols), which is the equivalent of about 92.5 Earth days. However, as of the writing of this article, the rover has endured for 14 years and 195 days, effectively exceeding its operational lifespan 55 times over. So if any rover can survive this enduring dust storm, its Opportunity!
In the meantime, multiple NASA missions are actively monitoring the storm in support of Opportunity and to learn more about the mechanics of Martian storms. By learning more about what causes these storms, and how smaller ones can merge to form global events, future robotic missions, crewed missions and (quite possibly) Martian colonists will be better prepared to deal with them.
The weather patterns on Mars are rather fascinating, owing to their particular similarities and differences with those of Earth. For one, the Red Planet experiences dust storms that are not dissimilar to storms that happen regularly here on Earth. Due to the lower atmospheric pressure, these storms are much less powerful than hurricanes on Earth, but can grow so large that they cover half the planet.
Recently, the ESA’s Mars Express orbiter captured images of the towering cloud front of a dust storm located close to Mars’ northern polar region. This storm, which began in April 2018, took place in the region known as Utopia Planitia, close to the ice cap at the Martian North Pole. It is one of several that have been observed on Mars in recent months, one which is the most severe to take place in years.
The images (shown above and below) were created using data acquired by the Mars Express‘ High Resolution Stereo Camera (HRSC). The camera system is operated by the German Aerospace Center (DLR), and managed to capture images of this storm front – which would prove to be the harbinger of the Martian storm season – on April 3rd, 2018, during its 18,039th orbit of Mars.
This storm was one of several small-scale dust storms that have been observered in recent months on Mars. A much larger storm emerged further southwest in the Arabia Terra region, which began in May of 2018 and developed into a planet-wide dust storm within several weeks.
Dust storms occur on Mars when the southern hemisphere experiences summer, which coincides with the planet being closer to the Sun in its elliptical orbit. Due to increased temperatures, dust particles are lifted higher into the atmosphere, creating more wind. The resulting wind kicks up yet more dust, creating a feedback loop that NASA scientists are still trying to understand.
Since the southern polar region is pointed towards the Sun in the summer, carbon dioxide frozen in the polar cap evaporates. This has the effect of thickening the atmosphere and increases surface pressure, which enhances the storms by helping to suspend dust particles in the air. Though they are common and can begin suddenly, Martian dust storms typically stay localized and last only a few weeks.
While local and regional dust storms are frequent, only a few of them develop into global phenomena. These storms only occur every three to four Martian years (the equivalent of approximately 6 to 8 Earth years) and can persist for several months. Such storms have been viewed many times in the past by missions like Mariner 9 (1971), Viking I (1971) and the Mars Global Surveyor (2001).
In 2007, a large storm covered the planet and darkened the skies over where the Opportunity rover was stationed – which led to two weeks of minimal operations and no communications. The most recent storm, which began back in May, has been less intense, but managed to create a state of perpetual night over Opportunity’s location in Perseverance Valley.
As a result, the Opportunity team placed the rover into hibernation mode and shut down communications in June 2018. Meanwhile, NASA’s Curiosity rover continues to explore the surface of Mars, thanks to its radioisotope thermoelectric generator (RTG), which does not rely on solar panels. By autumn, scientists expect the dust storm will weaken significantly, and are confident Opportunity will survive.
Understanding how global storms form and evolve on Mars will be critical for future solar-powered missions. It will also come in handy when crewed missions are conducted to the planet, not to mention space tourism and colonization!
Martian dust storms, which occur during the summer season in the planet’s southern hemisphere, can get pretty intense. Over the course of the past few weeks, a global dust storm has engulfed Mars and forced the Opportunity rover to suspend operations. Given that this storm is much like the one that took place back in 2007, which also raged for weeks, there have been concerns over how this development could affect rover operations.
Meanwhile the Curiosity rover managed to snap pictures of the thickening haze caused by the storm. Though Curiosity is on the other side of the planet from where Opportunity is currently located, atmospheric dust has been gradually increasing over it. But unlike Opportunity, which runs on solar power, Curiosity will remain unaffected by the global storm thanks to its nuclear-powered battery, and is therefore in a good position to study it.
As already noted, Martian storms occur during summer in the southern hemisphere, when sunlight warms dust particles and lifts them higher into the atmosphere, creating more wind. The resulting wind kicks up yet more dust, creating a feedback loop that NASA scientists are still trying to understand. Since the southern polar region is pointed towards the Sun in the summer, carbon dioxide frozen in the polar cap evaporates.
This has the effect of thickening the atmosphere and increasing the surface pressure, which enhances the process by helping suspend dust particles in the air. In some cases, the dust clouds can reach up to 60 km (40 mi) or more in elevation. Though they are common and can begin suddenly, Martian dust storms typically stay contained to a local area and last only about a weeks.
By contrast, the current storm has lasted for several weeks and is currently covering an area that would span North America and Russia combined. While smaller than the storm that took place back in 2007, this storm has intensified to the point where it created a perpetual state of night over the rover’s location in Perseverance Valley and led to a level of atmospheric opacity that is much worse than the 2007 storm.
When dust storms occur, scientists measure them based on their opacity level (tau) to determine how much sunlight they will prevent from reaching the surface. Whereas the 2007 storm had a tau level of about 5.5, this most recent storm reached an estimated tau of 10.8 earlier this month over the Perseverance Valley – where Opportunity is located.
The intensity of the storm also led Bruce Canton, deputy principal investigator of the Mars Color Imager (MARCI) camera onboard NASA’s Mars Reconnaissance Orbiter (MRO), to declare that the storm has officially become a “planet-encircling” (or “global”) dust event. Above the Gale Crater, where Curiosity is located, the tau reading is now above 8.0 – the highest ever recorded by the mission.
While the storm has some worried about the fate of Opportunity, which is Mars’ oldest active rover (having remained in operation for over 14 years), it is also an chance to address one of the greatest questions scientists have about Mars. For example, why do some storms span the entire planet and last for months while others are confined to small areas and and last only a week?
The animation (shown above) consists of a series of daily photos captures by Curiosity’s Mast Camera (Mastcam), which show the sky getting hazier over time. While taking these pictures, Curiosity was facing the crater rim, about 30 km (18.6) away from where it stands inside the crater. This sun-obstructing wall of haze is about six to eight times thicker than normal for this time of season.
Nevertheless, Curiosity’s engineers – which are based at NASA’s Jet Propulsion Laboratory in Pasadena, California – have studied how the growing dust storm could affect the rover’s instruments and concluded that it poses little risk. Ironically enough, the largest impact will be on the rover’s cameras, which require extra exposure time due to the low lighting conditions.
As Jim Watzin, the director of NASA’s Mars Exploration Program at the agency’s headquarters in Washington, explained in a NASA press release earlier this month:
“This is the ideal storm for Mars science. We have a historic number of spacecraft operating at the Red Planet. Each offers a unique look at how dust storms form and behave – knowledge that will be essential for future robotic and human missions.”
However, all dust events, regardless of size, help to shape the Martian surface. As such, studying their physics is critical to understanding the Martian climate, both past and present. As Rich Zurek, the chief scientist for the Mars Program Office at NASA’s Jet Propulsion Laboratory, indicated:
“Each observation of these large storms brings us closer to being able to model these events – and maybe, someday, being able to forecast them. That would be like forecasting El Niño events on Earth, or the severity of upcoming hurricane seasons.”
The ability to understand the causes and dynamics of Martian dust storms would not only lead to a better understand of how weather works on other planets, it would also be of immense importance if and and when humans begin traveling to the Red Planet on a regular basis. For instance, if SpaceX really does intend to bring tourists to Mars in the future, said tourists will want to avoid booking during “storm season”.
And if humans should choose to someday make Mars their home, they will need to know when planet-spanning dust storms are coming, especially since their habitats will likely be relying on wind and solar power. In the meantime, NASA and other space agencies will continue to monitor this storm and the Opportunity rover is expected to come through (fingers crossed!) unscathed!
NASA’s Opportunity mission can rightly be called the rover that just won’t quit. Originally, this robotic rover was only meant to operate on Mars for 90 Martian days (or sols), which works out to a little over 90 Earth days. However, since it made its landing on January 25th, 2004, it has remained in operation for 14 years, 4 months, and 18 days – exceeding its operating plan by a factor of 50!
However, a few weeks ago, NASA received disturbing news that potentially posed a threat to the “little rover that could”. A Martian storm, which has since grown to occupy an area larger than North America – 18 million km² (7 million mi²) – was blowing in over rover’s position in the Perseverance Valley. Luckily, NASA has since made contact with the rover, which is encouraging sign.
NASA’s Mars Reconnaissance Orbiter first detected the storm on Friday, June 1st, and immediately notified the Opportunity team to begin preparing contingency plans. The storm quickly grew over the next few days and resulted in dust clouds that raised the atmosphere’s opacity, which blocked out most of the sunlight from reaching the surface. This is bad news for the rover since it relies on solar panels for power and to recharge its batteries.
By Wednesday, June 6th, Opportunity’s power levels had dropped significantly and the rover was required to shift to minimal operations. But beyond merely limiting the rover’s operations, a prolonged dust storm also means that the rover might not be able to keep its energy-intensive survival heaters running – which protect its batteries from the extreme cold of Mars’ atmosphere.
The Martian cold is believed to be what resulted in the loss of the Spirit rover in 2010, Opportunity’s counterpart in the Mars Exploration Rover mission. Much like Opportunity, Spirit‘s mission as only meant to last for 90 days, but the rover managed to remain in operation for 2269 days (2208 sols) from start to finish. It’s also important to note that Opportunity has dealt with long-term storms before and emerged unscathed.
Back in 2007, a much larger storm covered the planet, which led to two weeks of minimal operations and no communications. However, the current storm has intensified as of Sunday morning (June 10th), creating a perpetual state of night over the rover’s location in Perseverance Valley and leading to a level of atmospheric opacity that is much worse than the 2007 storm.
Whereas the previous storm had an opacity level (tau) of about 5.5, this new storm has an estimated tau of 10.8. Luckily, NASA engineers received a transmission from the rover on Sunday, which was a positive indication since it proved that the rover still has enough battery charge to communicate with controllers at NASA’s Jet Propulsion Laboratory. This latest transmission also showed that the rover’s temperature had reached about -29 °C (-20 °F).
Full dust storms like this and the one that took place in 2007 are rare, but not surprising. They occur during summer in the southern hemisphere, when sunlight warms dust particles and lifts them higher into the atmosphere, creating more wind. That wind kicks up yet more dust, creating a feedback loop that NASA scientists are still trying to understand. While they can begin suddenly, they tend to last on the order of weeks or even months.
A saving grace about these storms is that they limit the extreme temperature swings, and the dust they kick up can also absorb solar radiation, thus raising ambient temperatures around Opportunity. In the coming weeks, engineers at the JPL will continue to monitor the rover’s power levels and ensure that it maintains the proper balance to keep its batteries in working order.
In the meantime, Opportunity’s science operations remain suspended and the Opportunity team has requested additional communications coverage from NASA’s Deep Space Network – the global system of antennas that communicates with all of the agency’s deep space missions. And if there’s one thing Opportunity has proven, it is that it’s capable of enduring!
Fingers crossed the storm subsides as soon as possible and the little rover that could once again emerges unscathed. At this rate, it could have many more years of life left in it!
It’s been a time of milestones for Mars rovers lately! Last month (on January 26th, 2018), NASA announced that the Curiosity rover had spent a total of 2,000 days on Mars, which works out to 5 years, 5 months and 21 days. This was especially impressive considering that the rover was only intended to function on the Martian surface for 687 days (a little under two years).
But when it comes to longevity, nothing has the Opportunity rover beat! Unlike Curiosity, which relied on a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) for power, the solar-powered Opportunity recently witnessed its five-thousandth sunrise on Mars. This means that the rover has remained in continuous operation for 5000 sols, which works out to 5137.46 Earth days.
This five-thousandth sunrise began on Friday, Feb. 16th, 2018 – roughly 14 Earth years (and 7.48 Martian years) after the rover first landed. From its position on the western rim of the Endeavour Crater, the sunrise appeared over the basin’s eastern rim, about 22 km (14 mi) away. This location, one-third of the way down “Perseverance Valley”, is more than 45 km (28 mi) from Opportunity’s original landing site.
This is especially impressive when you consider that the original science mission was only meant to last 90 sols (92.47 Earth days) and NASA did not expect the rover to survive its first Martian winter. And yet, the rover has not only survived all this time, it continues to send back scientific discoveries from the Red Planet. As John Callas, the Opportunity Project Manager at NASA’s Jet Propulsion Laboratory, explained in a NASA press release:
“Five thousand sols after the start of our 90-sol mission, this amazing rover is still showing us surprises on Mars… We’ve reached lots of milestones, and this is one more, but more important than the numbers are the exploration and the scientific discoveries.”
For instance, the rover has provided us with 225,000 images since its arrival, and revealed that ancient Mars was once home to extensive groundwater and surface water. Beginning in 2008, it began working its way across the Endeavour Crater in order to get a glimpse deeper into Mars’ past. By 2011, it had reached the crater’s edge and confirmed that mineral-rich water once flowed through the area.
At present, researchers are using Opportunity to investigate the processes that shaped Perseverance Valley, an area that descends down the slope of the western rim of Endeavour Crater. Here too, Opportunity has learned some fascinating things about the Red Planet. For instance, the rover has conducted observations of possible “rock stripes” in the valley, which could be indicative of its valley’s origin.
These stripes are of interest to scientists because of the way they resemble rock stripes that appear on mountain slopes here on Earth, which are the result of repeated cycles of freezing and thawing on wet soil. On Mauna Kea, for example, soil freezes every night, but is often dry due to the extreme elevation. This causes soils that have high concentrations of silt, sand and gravel to expand, pushing the larger particles up.
These particles then form stripes as they fall downhill, or are moved by wind or rainwater, and cause the ground to expand less in this space. This process repeats itself over and over, creating a pattern that leads to distinct stripes. As Opportunity observed, there are slopes within the Perseverance Valley where soil and gravel particles appear to have formed into rows that run parallel to the slope, alternating between rows that have more and less gravel.
In the case of the Perseverance Valley’s stripes, scientists are not sure how they formed, but think they could be the result of water, wind, downhill transport, other processes, or a combination thereof. Another theory posits that features like these could be the result of changes in Mars tilt (obliquity) which happen over the course of hundreds of thousands of years.
“One possible explanation of these stripes is that they are relics from a time of greater obliquity when snow packs on the rim seasonally melted enough to moisten the soil, and then freeze-thaw cycles organized the small rocks into stripes. Gravitational downhill movement may be diffusing them so they don’t look as crisp as when they were fresh.”
Having the chance to investigate these features is therefore quite the treat for the Opportunity science team. “Perseverance Valley is a special place, like having a new mission again after all these years.” said Arvidson. “We already knew it was unlike any place any Mars rover has seen before, even if we don’t yet know how it formed, and now we’re seeing surfaces that look like stone stripes. It’s mysterious. It’s exciting. I think the set of observations we’ll get will enable us to understand it.”
Given the state of the Martian surface, it is a safe bet that wind is largely responsible for the rock stripes observed in Perseverance Valley. In this respect, they would be caused by sand blown uphill from the crater floor that sorts larger particles into rows parallel to the slope. As Robert Sullivan, an Opportunity science-team member of Cornell University, explained:
“Debris from relatively fresh impact craters is scattered over the surface of the area, complicating assessment of effects of wind. I don’t know what these stripes are, and I don’t think anyone else knows for sure what they are, so we’re entertaining multiple hypotheses and gathering more data to figure it out.”
Despite being in service for a little over 14 years, and suffering its share of setbacks, Opportunity is once again in a position to reveal things about Mars’ past and how it evolved to become what it is today. Never let it be said that an old rover can’t reveal new secrets! If there’s one thing Opportunity has proven during its long history of service on Mars, it is that the underdog can make some of the greatest contributions.
When the Opportunity rover landed on Mars on January 25th, 2004, its mission was only meant to last for about 90 Earth days. But the little rover that could has exceeded all expectations by remaining in operation (as of the writing of this article) for a total of 13 years and 231 days and traveled a total of about 50 km (28 mi). Basically, Opportunity has continued to remain mobile and gather scientific data 50 times longer than its designated lifespan.
And according to a recent announcement from NASA’s Mars Exploration Program (MEP), the rover managed to survive yet another winter on Mars. Having endured the its eight Martian winter in a row, and with its solar panels in encouragingly clean condition, the rover will be in good shape for the coming dust-storm season. It also means the rover will live to see its 14th anniversary, which will take place on January 25th, 2018.
On Mars, a single year lasts the equivalent of 686.971 Earth days (or 1.88 Earth years). And since Mars’ axis is inclined 25.19° to its orbital plane (compared to Earth’s axial tilt of just over 23°), Mars also experiences seasons. However, these tend to last about twice as long as the seasons on Earth. And of course, the seasons on Mars’ are also much colder, with temperatures averaging about -63 °C (-82°F).
As Jennifer Herman, the power subsystem operations team lead for Opportunity at NASA’s Jet Propulsion Laboratory, recalled in a NASA MEP press statement:
“I didn’t start working on this project until about Sol 300, and I was told not to get too settled in because Spirit and Opportunity probably wouldn’t make it through that first Martian winter. Now, Opportunity has made it through the worst part of its eighth Martian winter.”
At present, both the Opportunity and Spirit rover are in Mars’ southern hemisphere. Here, the Sun appears in the northern sky during the fall and winter, so the rovers need to tilt their solar-arrays northward. Back in 2004, the Spirit rover had lost the use of two of its wheels, and could therefore not maneuver out of a sand trap it had become stuck in. As such, it was unable to tilt itself northward and did not survive its fourth Martian winter (in 2009).
However, Opportunity’s current position – Perseverance Valley, a fluid-carved region on the inner slope at the edge of the Endeavour Crater – meant that it was well-positioned to keep working through late fall and early winter this year. This was ensured by the stops the rover made at energy-favorable locations, where it would inspect local rocks, examine the valley’s shape and image the surrounding area, all the while absorbing ample energy from the Sun.
Five months ago, the rover entered the top of the valley, which runs eastward down the inner slope of the Endurance Crater’s western rim. Since that time, Opportunity has been conducting stops between drives at north-facing sites, which are situated along the southern edge of the channel. The rover team calls the sites “lily pads”, since these places are spots that the rover need to hop across during its mission.
This is necessary, given that Opportunity does not rely on a radioisotope thermoelectric generator like Curiosity does. While winter conditions affect the use of electrical heaters and batteries on both rovers, Opportunity is different in that it’s activities are more subject to seasonal change. Whereas Curiosity will simply allocate less energy to performing tasks in the winter, Opportunity needs to pick its routes to ensure it stays powered up.
During some of its previous winters, the Opportunity rover was not as well-situated as it currently is. During its fifth winter (2011-2012) the rover spent 19 weeks at one spot because no other places that allowed for a northward-facing tilt were available within driving distance. On the other hand, its first winter (2004-2005) was spent in the southern half of the Endurance Crater, where all grounds are favorable since they face north.
As the person who is chiefly responsible for advising other mission scientists on how much energy Opportunity has available on each Martian day (sol) for conducting activities like driving and observing – a task she performs for Curiosity as well – Herman understand the relationship between power usage and the seasons all too well. “Relying on solar energy for Opportunity keeps us constantly aware of the season on Mars and the terrain that the rover is on, more than for Curiosity,” she said.
Another factor which can influence Opportunity‘s power supply is how much dust is in the sky and how much of it gets onto the rover’s solar arrays. This is highly-dependent on prevailing wind conditions, which can both stir up dust storms and clear away dust deposits on the rover – basically, they are a real mixed blessing! During autumn and winter in the southern-hemisphere, the skies are generally clear where Opportunity operates.
Spring and summer is when the storms are most common in Mars’ southern hemisphere, though they don’t happen every year. The latest example took place in 2007, which led to a severe reduction in the amount of sunlight (and hence, solar energy) Spirit and Opportunity were able to receive. This required both rovers to enact emergency protocols and reduce the amount of operations and communications they conducted.
The amount of dust on the rover’s solar arrays going into autumn can also vary from year to year. This year, the array was dustier than in all but one of the previous Martian autumns it experienced. Luckily, as Herman explained, things worked out for the rover:
“We were worried that the dust accumulation this winter would be similar to some of the worst winters we’ve had, and that we might come out of the winter with a very dusty array, but we’ve had some recent dust cleaning that was nice to see. Now I’m more optimistic. If Opportunity’s solar arrays keep getting cleaned as they have recently, she’ll be in a good position to survive a major dust storm. It’s been more than 10 Earth years since the last one and we need to be vigilant.”
In the coming months, the Opportunity team hopes to investigate how the Perseverance Valley was cut into the rim of the Endeavor crater. As Matt Golombek, an Opportunity Project Scientist at JPL, related:
“We have not been seeing anything screamingly diagnostic, in the valley itself, about how much water was involved in the flow. We may get good diagnostic clues from the deposits at the bottom of the valley, but we don’t want to be there yet, because that’s level ground with no more lily pads.”
With its eighth winter finished and Opportunity still in good working order, we can expect the tenacious rover to keep turning up interesting finds on Mars. These include clues about Mars’ warmer, wetter past, which likely included a standing body of water in the Endeavor crater. And assuming conditions are favorable in the coming year, we can expect that Opportunity will continue to push the boundaries of both science and its own endurance!
5 years after a heart throbbing Martian touchdown, Curiosity is climbing Vera Rubin Ridge in search of “aqueous minerals” and “clays” for clues to possible past life while capturing “truly breathtaking” vistas of humongous Mount Sharp – her primary destination – and the stark eroded rim of the Gale Crater landing zone from ever higher elevations, NASA scientists tell Universe Today in a new mission update.
“Curiosity is doing well, over five years into the mission,” Michael Meyer, NASA Lead Scientist, Mars Exploration Program, NASA Headquarters told Universe Today in an interview.
“A key finding is the discovery of an extended period of habitability on ancient Mars.”
The car-sized rover soft landed on Mars inside Gale Crater on August 6, 2012 using the ingenious and never before tried “sky crane” system.
A rare glimpse of Curiosity’s arm and turret mounted skyward pointing drill is illustrated with our lead mosaic from Sol 1833 of the robot’s life on Mars – showing a panoramic view around the alien terrain from her current location in October 2017 while actively at work analyzing soil samples.
“Your mosaic is absolutely gorgeous!’ Jim Green, NASA Director Planetary Science Division, NASA Headquarters, Washington D.C., told Universe Today
“We are at such a height on Mt Sharp to see the rim of Gale Crater and the top of the mountain. Truly breathtaking.”
The rover has ascended more than 300 meters in elevation over the past 5 years of exploration and discovery from the crater floor to the mountain ridge. She is driving to the top of Vera Rubin Ridge at this moment and always on the lookout for research worthy targets of opportunity.
Additionally, the Sol 1833 Vera Rubin Ridge mosaic, stitched by the imaging team of Ken Kremer and Marco Di Lorenzo, shows portions of the trek ahead to the priceless scientific bounty of aqueous mineral signatures detected by spectrometers years earlier from orbit by NASA’s fleet of Red Planet orbiters.
“Curiosity is on Vera Rubin Ridge (aka Hematite Ridge) – it is the first aqueous mineral signature that we have seen from space, a driver for selecting Gale Crater,” NASA HQ Mars Lead Scientist Meyer elaborated.
“And now we have access to it.”
The Sol 1833 photomosaic illustrates Curiosity maneuvering her 7 foot long (2 meter) robotic arm during a period when she was processing and delivering a sample of the “Ogunquit Beach” for drop off to the inlet of the CheMin instrument earlier in October. The “Ogunquit Beach” sample is dune material that was collected at Bagnold Dune II this past spring.
The sample drop is significant because the drill has not been operational for some time.
“Ogunquit Beach” sediment materials were successfully delivered to the CheMin and SAM instruments over the following sols and multiple analyses are in progress.
To date three CheMin integrations of “Ogunquit Beach” have been completed. Each one brings the mineralogy into sharper focus.
What’s the status of the rover health at 5 years, the wheels and the drill?
“All the instruments are doing great and the wheels are holding up,” Meyer explained.
“When 3 grousers break, 60% life has been used – this has not happened yet and they are being periodically monitored. The one exception is the drill feed (see detailed update below).”
NASA’s 1 ton Curiosity Mars Science Laboratory (MSL) rover is now closer than ever to the mineral signatures that were the key reason why Mount Sharp was chosen as the robots landing site years ago by the scientists leading the unprecedented mission.
Along the way from the ‘Bradbury Landing’ zone to Mount Sharp, six wheeled Curiosity has often been climbing. To date she has gained over 313 meters (1027 feet) in elevation – from minus 4490 meters to minus 4177 meters today, Oct. 19, 2017, said Meyer.
The low point was inside Yellowknife Bay at approx. minus 4521 meters.
VRR alone stands about 20 stories tall and gains Curiosity approx. 65 meters (213 feet) of elevation to the top of the ridge. Overall the VRR traverse is estimated by NASA to take drives totaling more than a third of a mile (570 m).
“Vera Rubin Ridge” or VRR is also called “Hematite Ridge.” It’s a narrow and winding ridge located on the northwestern flank of Mount Sharp. It was informally named earlier this year in honor of pioneering astrophysicist Vera Rubin.
The intrepid robot reached the base of the ridge in early September.
The ridge possesses steep cliffs exposing stratifications of large vertical sedimentary rock layers and fracture filling mineral deposits, including the iron-oxide mineral hematite, with extensive bright veins.
VRR resists erosion better than the less-steep portions of the mountain below and above it, say mission scientists.
What’s ahead for Curiosity in the coming weeks and months exploring VRR before moving onward and upwards to higher elevation?
“Over the next several months, Curiosity will explore Vera Rubin Ridge,” Meyer replied.
“This will be a big opportunity to ground-truth orbital observations. Of interest, so far, the hematite of VRR does not look that different from what we have been seeing all along the Murray formation. So, big question is why?”
“The view from VRR also provides better access to what’s ahead in exploring the next aqueous mineral feature – the clay, or phyllosilicates, which can be indicators of specific environments, putting constraints on variables such as pH and temperature,” Meyer explained.
The clay minerals or phyllosilicates form in more neutral water, and are thus extremely scientifically interesting since pH neutral water is more conducive to the origin and evolution of Martian microbial life forms, if they ever existed.
How far away are the clays ahead and when might Curiosity reach them?
“As the crow flies, the clays are about 0.5 km,” Meyer replied. “However, the actual odometer distance and whether the clays are where we think they are – area vs. a particular location – can add a fair degree of variability.”
The clay rich area is located beyond the ridge.
Over the past few months Curiosity make rapid progress towards the hematite-bearing location of Vera Rubin Ridge after conducting in-depth exploration of the Bagnold Dunes earlier this year.
“Vera Rubin Ridge is a high-standing unit that runs parallel to and along the eastern side of the Bagnold Dunes,” said Mark Salvatore, an MSL Participating Scientist and a faculty member at Northern Arizona University, in a mission update.
“From orbit, Vera Rubin Ridge has been shown to exhibit signatures of hematite, an oxidized iron phase whose presence can help us to better understand the environmental conditions present when this mineral assemblage formed.”
Curiosity is using the science instruments on the mast, deck and robotic arm turret to gather detailed research measurements with the cameras and spectrometers. The pair of miniaturized chemistry lab instruments inside the belly – CheMin and SAM – are used to analyze the chemical and elemental composition of pulverized rock and soil gathered by drilling and scooping selected targets during the traverse.
A key instrument is the drill which has not been operational. I asked Meyer for a drill update.
“The drill feed developed problems retracting (two stabilizer prongs on either side of the drill retract, controlling the rate of drill penetration),” Meyer replied.
“Because the root cause has not been found (think FOD) and the concern about the situation getting worse, the drill feed has been retracted and the engineers are working on drilling without the stabilizing prongs.”
“Note, a consequence is that you can still drill and collect sample but a) there is added concern about getting the drill stuck and b) a new method of delivering sample needs to be developed and tested (the drill feed normally needs to be moved to move the sample into the chimera). One option that looks viable is reversing the drill – it does work and they are working on the scripts and how to control sample size.”
Ascending and diligently exploring the sedimentary lower layers of Mount Sharp, which towers 3.4 miles (5.5 kilometers) into the Martian sky, is the primary destination and goal of the rover’s long term scientific expedition on the Red Planet.
“Lower Mount Sharp was chosen as a destination for the Curiosity mission because the layers of the mountain offer exposures of rocks that record environmental conditions from different times in the early history of the Red Planet. Curiosity has found evidence for ancient wet environments that offered conditions favorable for microbial life, if Mars has ever hosted life,” says NASA.
Stay tuned. In part 2 we’ll discuss the key findings from Curiosity’s first 5 years exploring the Red Planet.
As of today, Sol 1850, Oct. 19, 2017, Curiosity has driven over 10.89 miles (17.53 kilometers) since its August 2012 landing inside Gale Crater from the landing site to the ridge, and taken over 445,000 amazing images.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
It is a well-known fact that today, Mars is a very cold and dry place. Whereas the planet once had a thicker atmosphere that allowed for warmer temperatures and liquid water on its surface, the vast majority of water there today consists of ice that is located in the polar regions. But for some time, scientists have speculated that there may be plenty of water in subsurface ice deposits.
If true, this water could be accessed by future crewed missions and even colonization efforts, serving as a source of rocket fuel and drinking water. Unfortunately, a new study led by scientists from the Smithsonian Institution indicates that the subsurface region beneath Meridiani Planum could be ice-free. Though this may seem like bad news, the study could help point the way towards accessible areas of water ice on Mars.
Despite being one of the most intensely explored regions on Mars, particularly by missions like the Opportunity rover, the subsurface structure of Meridiani Planum has remained largely unknown. To remedy this, the science team led by Dr. Watters examined data that had been collected by the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instrument aboard the ESA’s Mars Express orbiter.
Developed by researchers at the University of Rome in partnership with NASA’s Jet Propulsion Laboratory (and with the help of private contractors), this device used low-frequency radio pulses to study Mars’ ionosphere, atmosphere, surface, and interior structure. The way these pulses penetrated into certain materials and were reflected back to the orbiter was then used to determine the bulk density and compositions of those materials.
After examining the Meridiani Planum region, the Mars Express probe obtained readings that indicated that the subsurface area had a relatively low dielectric constant. In the past, these kinds of readings have been interpreted as being due to the presence of pure water ice. And in this case, the readings seemed to indicate that the subsurface was made up of porous rock that was filled with water ice.
However, with the help of newly-derived compaction models for Mars, the team concluded that these signals could be the result of ice-free, porous, windblown sand (aka. eolian sands). They further theorized that the Meridiani Planum region, which is characterized by some rather unique physiographic and hydrologic features, could have provided an ideal sediment trap for these kinds of sands.
“The relatively low gravity and the cold, dry climate that has dominated Mars for billions of years may have allowed thick eolian sand deposits to remain porous and only weakly indurated,” they concluded. “Minimally compacted sedimentary deposits may offer a possible explanation for other nonpolar region units with low apparent bulk dielectric constants.”
“It’s very revealing that the low dielectric constant of the Meridiani Planum deposits can be explained without invoking pore-filling ice. Our results suggest that caution should be exercised in attributing non-polar deposits on Mars with low dielectric constants to the presence of water ice.”
On its face, this would seem like bad news to those who were hoping that the equatorial regions on Mars might contain vast deposits of accessible water ice. It has been argued that when crewed missions to Mars begin, this ice could be accessed in order to supply water for surface habitats. In addition, ice that didn’t need to come from there could also be used to manufacture hydrazine fuel for return missions.
This would reduce travel times and the cost of mounting missions to Mars considerably since the spacecraft would not need to carry enough fuel for the entire journey, and would therefore be smaller and faster. In the event that human beings establish a colony on Mars someday, these same subsurface deposits could also used for drinking, sanitation, and irrigation water.
As such, this study – which indicates that low dielectric constants could be due to something other than the presence of water ice – places a bit of a damper on these plans. However, understood in context, it provides scientists with a means of locating subsurface ice. Rather than ruling out the presence of subsurface ice away from the polar regions entirely, it could actually help point the way to much-needed deposits.
One can only hope that these regions are not confined to the polar regions of the planet, which would be far more difficult to access. If future missions and (fingers crossed!) permanent outposts are forced to pump in their water, it would be far more economical to do from underground sources, rather than bringing it in all the way from the polar ice caps.
From the precipice of “Perseverance Valley” NASA’s teenaged Red Planet robot Opportunity has begun the historic first ever descent of an ancient Martian gully – that’s simultaneously visually and scientifically “tantalizing” – on an expedition to discern ‘How was it carved?’; by water or other means, Jim Green, NASA’s Planetary Sciences Chief tells Universe Today.
Since water is an indispensable ingredient for life as we know it, the ‘opportunity’ for Opportunity to study a “possibly water-cut” gully on Mars for the first time since they were discovered over four decades ago by NASA orbiters offers a potential scientific bonanza.
“Gullies on Mars have always been of intense interest since first observed by our orbiters,” Jim Green, NASA’s Planetary Sciences Chief explained to Universe Today.
“How were they carved? muses Green. “Water is a natural explanation but this is another planet. Now we have a chance to find out for real!”
Their origin and nature has been intensely debated by researchers for decades. But until now the ability to gather real ‘ground truth’ science by robotic or human explorers has remained elusive.
“This will be the first time we will acquire ground truth on a gully system that just might be formed by fluvial processes,” Ray Arvidson, Opportunity Deputy Principal Investigator of Washington University in St. Louis, told Universe Today.
“Perseverance Valley” is located along the eroded western rim of gigantic Endeavour crater – as illustrated by our exclusive photo mosaics herein created by the imaging team of Ken Kremer and Marco Di Lorenzo.
After arriving at the upper entryway to “Perseverance Valley” the six wheeled rover drove back and forth to gather high resolution imagery of the inner slope for engineers to create a 3D elevation map and plot a safe driving path down – as illustrated in our lead mosaic showing the valley and extensive wheel tracks at left, center and right.
Having just this week notched an astounding 4800 Sols roving the Red Planet, NASA’s resilient Opportunity rover has started driving down from the top of “Perseverance Valley” from the spillway overlooking the upper end of the ancient fluid-carved Martian valley into the unimaginably vast eeriness of alien Endeavour crater.
Water, ice or wind may have flowed over the crater rim and into the crater from the spillway.
“It is a tantalizing scene,” said Opportunity Deputy Principal Investigator Ray Arvidson of Washington University in St. Louis, in a statement. “You can see what appear to be channels lined by boulders, and the putative spillway at the top of Perseverance Valley. We have not ruled out any of the possibilities of water, ice or wind being responsible.”
“With the latest drive on sol 4782, Opportunity began the long drive down the floor of Perseverance Valley here on Endeavour crater, says Larry Crumpler, a rover science team member from the New Mexico Museum of Natural History & Science.
“This is rather historic in that it represents the first time that a rover has driven down an apparent water-cut valley on Mars. Over the next few months Opportunity will explore the floor and sides of the valley for evidence of the scale and timing of the fluvial activity, if that is what is represents.”
NASA’s unbelievably long lived Martian robot reached a “spillway” at the top of “Perseverance Valley” in May after driving southwards for weeks from the prior science campaign at a crater rim segment called “Cape Tribulation.”
“Investigations in the coming weeks will “endeavor” to determine whether this valley was eroded by water or some other dry process like debris flows,” explains Crumpler.
“It certainly looks like a water cut valley. But looks aren’t good enough. We need additional evidence to test that idea.”
The valley slices downward from the crest line through the rim from west to east at a breathtaking slope of about 15 to 17 degrees – and measures about two football fields in length!
Huge Endeavour crater spans some 22 kilometers (14 miles) in diameter on the Red Planet. Perseverance Valley slices eastwards at approximately the 8 o’clock position of the circular shaped crater. It sits just north of a rim segment called “Cape Byron.”
Why go and explore the gully at Perseverance Valley?
“Opportunity will traverse to the head of the gully system [at Perseverance] and head downhill into one or more of the gullies to characterize the morphology and search for evidence of deposits,” Arvidson elaborated to Universe Today.
“Hopefully test among dry mass movements, debris flow, and fluvial processes for gully formation. The importance is that this will be the first time we will acquire ground truth on a gully system that just might be formed by fluvial processes. Will search for cross bedding, gravel beds, fining or coarsening upward sequences, etc., to test among hypotheses.”
Exploring the ancient valley is the main science destination of the current two-year extended mission (EM #10) for the teenaged robot, that officially began Oct. 1, 2016. It’s just the latest in a series of extensions going back to the end of Opportunity’s prime mission in April 2004.
Before starting the gully descent, Opportunity conducted a walkabout at the top of the Perseverance Valley in the spillway to learn more about the region before driving down.
“The walkabout is designed to look at what’s just above Perseverance Valley,” said Opportunity Deputy Principal Investigator Ray Arvidson of Washington University in St. Louis, in a statwemwent. “We see a pattern of striations running east-west outside the crest of the rim.”
“We want to determine whether these are in-place rocks or transported rocks,” Arvidson said. “One possibility is that this site was the end of a catchment where a lake was perched against the outside of the crater rim. A flood might have brought in the rocks, breached the rim and overflowed into the crater, carving the valley down the inner side of the rim. Another possibility is that the area was fractured by the impact that created Endeavour Crater, then rock dikes filled the fractures, and we’re seeing effects of wind erosion on those filled fractures.”
Having begun the long awaited gully descent, further movements are temporarily on hold since the start of the solar conjunction period which blocks communications between Mars and Earth for about the next two weeks, since Mars is directly behind the sun.
In the meantime, Opportunity will still collect very useful panoramic images and science data while standing still.
The solar conjunction moratorium on commanding extends from July 22 to Aug. 1, 2017.
As of today, July 27, 2017, long lived Opportunity has survived over 4800 Sols (or Martian days) roving the harsh environment of the Red Planet.
Opportunity has taken over 221,625 images and traversed over 27.95 miles (44.97 kilometers.- more than a marathon.
See our updated route map below. It shows the context of the rovers over 13 year long traverse spanning more than the 26 mile distance of a Marathon runners race.
The rover surpassed the 27 mile mark milestone on November 6, 2016 (Sol 4546) and will soon surpass the 28 mile mark.
As of Sol 4793 (July 18, 2017) the power output from solar array energy production is currently 332 watt-hours with an atmospheric opacity (Tau) of 0.774 and a solar array dust factor of 0.534, before heading into another southern hemisphere Martian winter later in 2017. It will count as Opportunity’s 8th winter on Mars.
Meanwhile Opportunity’s younger sister rover Curiosity traverses up the lower sedimentary layers at the base of Mount Sharp.
And NASA continues building the next two robotic missions due to touch down in 2018 and 2020.
NASA as well is focusing its human spaceflight efforts on sending humans on a ‘Journey to Mars’ in the 2030s with the Space Launch System (SLS) mega rocket and Orion deep space crew capsule.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.