“Getting samples from this unique area will revolutionize how we think about Mars and its ability to harbour life,” says Thomas Zurbuchen, NASA’s associate administrator for science, who chose Jezero over three other finalists.
Still undecided is whether the rover would embark on a long drive to a second site after it finishes surveying Jezero. Some scientists want the rover to roll 28 kilometres to a location dubbed Midway, where it could sample some of the most ancient rocks known on the red planet.
Either way, the 2020 rover will set the direction of NASA’s Mars programme for years to come, says Lori Glaze, acting director of the agency’s planetary-sciences division in Washington DC.
Jezero was formed billions of year ago by a meteorite impact. At one point, water filled it to a depth of about 250 metres, and then flowed out — leaving behind sediments that could contain a record of life, if any ever existed there. “You see a canyon coming in and depositing the sediment,” says Kenneth Farley, the mission’s project scientist. “That is a major attraction.”
Jezero is also home to carbonate rocks, whose chemistry could reveal how the lake’s water and the Martian atmosphere interacted in the distant past, Farley says. And a wider variety of rocks found upstream could have been swept into the crater, where the rover could study them as well.
The varied geology of Jezero and its surroundings helped Jezero to beat out other potential destinations for the 2020 rover. They include Northeast Syrtis, which contains some of the oldest rocks on Mars, and Columbia Hills, which the Spirit rover explored between 2004 and 2011.
The US$2.4-billion rover is slated to launch in July 2020 and land on Mars in February 2021. It will carry 37 sample tubes and 5 spares, which it will fill using its robotic arm — an attachment designed to drill long, slender cylinders of Martian rock. The rover will collect a variety of samples as it explores the red planet, and eventually set them down for a future mission to retrieve.
NASA has not yet developed a detailed plan for transporting the samples back to Earth. Zurbuchen says that it hopes to send a mission to Mars in the late 2020s to retrieve the rocks, and return them to Earth in the early 2030s.
NASA’s next Mars rover will land in Jezero crater, which once hosted a lake and a river delta
Update: NASA today announced the destination for its next Mars rover, due for launch in 2020. The agency said it would send the rover to the 50-kilometer-wide Jezero crater, which billions of years ago harbored a lake that half filled the 500-meter-deep basin. The crater also contains within its rim a fossilized river delta, the sediments from a river that spilled into the crater—a promising place to search for evidence of past life. “Getting samples from this unique area will revolutionize how we think about Mars and its ability to harbor life,” Thomas Zurbuchen, NASA’s associate administrator for science in Washington, D.C., said in a press conference.
Mars scientists also wanted to visit a nearby site, called Northeast Syrtis, which contains rocks formed in the presence of mineral springs. So NASA dangled the possibility of a two-for-one special—that after visiting Jezero, the rover might climb out of the crater and travel 25 kilometers to Midway, a site that contains many of the same rocks as Northeast Syrtis. Zurbuchen said the possibility of an extended mission to Midway is not ruled out, but he wants the team to focus on Jezero crater for now. “Come the time, we want to talk about it,” he said. “But at this moment we’re focusing on the prime mission.”
The 2020 rover will be tasked with gathering and caching rock and soil samples for eventual return to Earth by subsequent missions. At a workshop attended by hundreds of Mars scientists a month ago, Jezero was one of the leading landing sites. Here is our previous story from 10 October:
Sometimes, a problem really can be solved by meeting halfway. For the past 4 years, planetary scientists have wrestled over where to send NASA's next Mars rover, a $2.5 billion machine to be launched in 2020 that will collect rock samples for eventual return to Earth. Next week, nearly 200 Mars scientists will gather for a final landing site workshop in Glendale, California, where they will debate the merits of the three candidate sites that rose to the top of previous discussions. Two, Jezero and Northeast Syrtis, hold evidence of a fossilized river delta and mineral springs, both promising environments for ancient life. Scientists yearn to visit both, but they are 37 kilometers apart—much farther than any martian rover has traveled except Opportunity.
Now, the Mars 2020 science team is injecting a compromise site, called Midway, into the mix. John Grant, a planetary scientist at the Smithsonian Institution's Center for Earth and Planetary Studies at the National Air and Space Museum in Washington, D.C., who co-leads the landing site workshops, says the team wanted to know whether a rover might be able to study the terrains found at Jezero and Northeast Syrtis by landing somewhere in the middle.
So far, the answer appears to be yes. The Mars 2020 rover borrows much from the design of the Curiosity rover that has been exploring another Mars site for 6 years. But it includes advances such as a belly-mounted camera that will help it avoid landing hazards during its harrowing descent to the surface. This capability allowed scientists to consider Midway, just 25 kilometers from Jezero and close enough to drive there. At the same time, Midway's rocks resemble those of Northeast Syrtis, says Bethany Ehlmann, a planetary scientist at the California Institute of Technology (Caltech) in Pasadena and member of the Mars 2020 science team.
Midway and Northeast Syrtis both hail from a time, some 4 billion years ago, when Mars was warmer and wetter. Surveys from orbit suggest the sites harbor rocks that formed underground in the presence of water and iron, a potential food for microbes. The rocks, exposed on the flanks of mesas, include a layer of carbonate deposits that many scientists believe were formed by underground mineral springs. Sheltered from a harsh surface environment, these springs would have been hospitable to life, Ehlmann says. "We should go where the action was."
Nearby Jezero crater has its own allure, etched on the surface: a fossilized river delta. Nearly 4 billion years ago, water spilled into the crater, creating the delta. "It's right there," says Ray Arvidson, a planetary geologist at Washington University in St. Louis, Missouri. "It's beautiful." Geologists know deltas concentrate and preserve the remnants of life; they can see that on Earth in offshore deposits of oil—itself preserved organic matter—fed by deltas like the Mississippi's. New work to be presented at the workshop by Briony Horgan, a planetary scientist at Purdue University in West Lafayette, Indiana, will show that Jezero crater has a bathtub ring of carbonate—a strong sign that it once contained a lake. On Earth, such layers are often home to stromatolites, cauliflowerlike minerals created by ancient microbial life.
Right now, the Mars 2020 team favors landing at Jezero and driving uphill to Midway, says Matt Golombek, a planetary scientist at NASA's Jet Propulsion Lab (JPL) in Pasadena, and the other workshop co-leader. For the past year, the team has scoured potential routes between the two. "We haven't identified any deal-breakers," says Ken Farley, the mission's project scientist and a Caltech geologist. The rover's advanced autonomous driving should allow it to cover more ground than Curiosity, which often stops to plan routes. Even so, the path from Jezero to Midway would take nearly 2 years, Farley says. That means the rover could explore only one site during its primary 2-year mission, when it must drill and store 20 rock cores, to be picked up by future sample return missions. Exploration of the second site would have to come during an extended mission, after the rover's warranty expires. "The further away you land from your gold mine, the higher the risk you might not get there," Arvidson says.
A happy medium
Jezero and Northeast Syrtis, two attractive landing sites for NASA's Mars 2020 rover, are close to each other. A new landing site, Midway, might allow the rover to study rocks from both terrains.
Left out of those plans is the last leading candidate site: Columbia Hills. "I have a sense there's a hill to climb," says the site's chief advocate, Steven Ruff, a planetary scientist at Arizona State University in Tempe. "I'll go in with a lot of questions of whether they can make that drive between Midway and Jezero." Columbia Hills sits within the large Gusev crater that the Spirit rover explored from 2004 to 2010. Driving backward while dragging a bad front wheel, Spirit gouged a trench that revealed opaline silica, a mineral that on Earth is a sure sign of life-supporting hot springs. Ruff has even proposed that the martian silica deposits are stromatolites.
The engineers building Mars 2020 will be glad to settle on a destination, says Matt Wallace, the rover's deputy project manager at JPL. The lab's clean room is starting to fill up. The "sky crane" that will lower the rover to the surface is done. The spacecraft that will shepherd the rover to Mars is nearly complete—it just needs a heat shield, which is being rebuilt after testing revealed a crack. Several weeks ago, the chassis of the rover arrived and is now being filled with computers, batteries, and other electronics. Assembly of its complex drilling and sample storage system is underway, with other scientific instruments due by the end of February. "This is the mad scramble," Farley adds. "It is full bore get it done, get it done now."
At the workshop's end, scientists will vote on the candidates, followed by a closed-door meeting of the rover team to make a final choice. Engineers have deemed the sites safe for landing, Golombek adds, so it will come down to the science. The team's recommendation won't be the final word—the choice is ultimately up to NASA science chief Thomas Zurbuchen. But expect a decision within the next few months, if not sooner.
Mars 2020 rover mission camera system ‘Mastcam-Z’ testing begins at ASU
Arizona State University research technician and Mars 2020 Mastcam-Z calibration engineer Andy Winhold waited patiently on the loading dock of ASU’s Interdisciplinary Science and Technology Building IV in anticipation of the arrival of a very special delivery.
On board the delivery truck was precious cargo from Malin Space Science Systems, a test model of “Mastcam-Z,” the mast-mounted camera system for NASA’s Mars 2020 rover mission.
The Mastcam-Z team tests the engineering model in ASU’s cleanrooms.
Mastcam-Z is being designed, built and tested under the direction of principal investigator Jim Bell, of ASU’s School of Earth and Space Exploration. The dual camera system can zoom in (hence the ‘Z’ in “’Mastcam-Z’), focus and take 3D pictures and panoramas at a variety of scales. This will allow the Mars 2020 rover to provide a detailed examination of both close and distant objects.
The test model that arrived on the Tempe campus in November, otherwise known as an engineering qualification model or EQM, is an important step in designing and building instruments for space. These models not only serve as a way to run the instruments through the rigors of launch and functionality in space, they also serve as a way for the instrument team to evaluate the design and testing plans before the final cameras are fully assembled.
Testing the Mastcam-Z engineering model
The engineering model essentially allows the team to do a "dry run" through the complete design and build process of the instrument before the final versions of the cameras are complete.
“Parts may take longer to build than expected, a certain assembly step may be more difficult than initially thought or resources from third parties could become scarce on short notice,” Winhold said. “These are all things we can learn about and prepare for in advance using the engineering model.”
The team first verifies that the test instrument operates correctly in terms of parts, power consumption and software. They also use the model to ensure the instrument meets mission requirements in terms of functionality, size and weight. “For Mastcam-Z, one of the primary interests with the engineering model was evaluating the instrument’s ability to change focal length — or zoom,” Winhold said.
Specifically, the team tested the engineering model in the thermal vacuum chamber, located in ASU’s Interdisciplinary Science and Technology Building IV, to confirm that their support equipment was designed appropriately and allowed the camera to be placed securely in the chamber and view out the chamber's window clearly. They also timed the tests so they knew how long testing the actual cameras will take, and they tested the IT network's ability to share data quickly between people inside the cleanroom and other support team members outside of the room and around the world.
Winhold describes his role on the mission as similar to someone playing the game "Operation," where the patient is the Mastcam-Z cameras and the tweezers are the support pieces.
“But in my case,” said Winhold, “I'm only shown pictures of the board game, and based on those pictures I need to design and create the best tweezers for removing ailments without hurting the patient.”
And according to the team, the testing has been a success so far.
“We had a few hiccups we worked around, like cables not being long enough, not understanding best communication procedures, that sort of thing; but nothing truly unexpected,” Winhold said. “That's exactly how we like things. In testing equipment that will be going to space, a boring day that goes according to procedure is a good one.”
Next steps for the Mastcam-Z team
In December, the actual Mastcam-Z flight cameras will arrive on the ASU Tempe campus for testing. They will then be delivered to NASA's Jet Propulsion Laboratory and installed on the Mars 2020 rover, which will launch in summer 2020, landing on Mars in February 2021. The mission is expected to last at least one Mars year (687 Earth days).
“The tests we ran on the engineering unit at ASU are almost identical to the tests we'll be running on the actual cameras when they arrive,” Winhold said.
Once the instrument is finalized and installed in the Mars 2020 rover, the engineering model continues to have a purpose.
“Largely it is considered a ‘flight spare’ and will be a back-up unit should something happen to the flight cameras before launch,” Winhold explained. “Once the rover launches in the summer of 2020 we won't be able to do any hands-on interaction with the flight cameras, though, so we’ll have the engineering model as a reference for possible problem solving and as a reference for subsequent rover missions.”
The cameras weigh about 8.8 pounds and will produce images of color quality similar to that of a consumer digital HD camera (2 megapixels). The cameras will help other Mars 2020 experiments on the rover by looking at the whole landscape and identifying rocks and soil (regolith) that deserve a closer look by other instruments. They will also spot important rocks for the rover to sample and cache on the surface of Mars, for eventual return (by a future mission) to Earth.
Mastcam-Z's purpose is to take high resolution panoramic color and 3D images of the Martian surface and features in the atmosphere with a zoom lens to magnify distant targets. It will be mounted on the Mars 2020 rover mast at the eye level of a 6-foot-5-inch person. The two cameras are separated by 9.5 inches to provide stereo vision. These cameras, with their all-seeing sharp vision, will provide images for science team members to pick out the best rocks, to hunt for evidence of past habitability recorded in the geology and texture of the landscape, and to look for signs of past water on Mars.
Mastcam-Z’s principal investigator is Professor Jim Bell of the School of Earth and Space Exploration. The deputy principal investigator is Dr. Justin Maki of NASA's Jet Propulsion Laboratory, the Planetary Society serves as the instrument’s education and public outreach partner, and the prime subcontractor for instrument development is Malin Space Science Systems, Inc.
NASA's Mars 2020 rover mission
The Mars 2020 rover mission is part of NASA's Mars Exploration Program, a long-term effort of robotic exploration of the Red Planet. The Mars 2020 mission addresses high-priority science goals for Mars exploration, including key questions about the potential for life on Mars. The mission also seeks to gather knowledge and to demonstrate technologies that address the challenges of future human expeditions to Mars. These include testing a method for producing oxygen from the Martian atmosphere, identifying other resources (such as subsurface water), improving landing techniques, and characterizing weather, dust, and other potential environmental conditions that could affect future astronauts living and working on Mars.