Mars 2020 Perseverance rover mission of NASA/JPL
Mars 2020 Perseverance Mission Overview. The Mars 2020 Perseverance (former 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 Perseverance mission addresses high-priority science goals for Mars exploration, including key questions about the potential for life on Mars. The mission takes the next step by not only seeking signs of habitable conditions on Mars in the ancient past, but also searching for signs of past microbial life itself. The Mars 2020 Perseverance rover introduces a drill that can collect core samples of the most promising rocks and soils and set them aside in a "cache" on the surface of Mars. The mission also provides opportunities to gather knowledge and 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. 1) 2) 3)
The mission is timed for a launch opportunity in July/August 2020 when Earth and Mars are in good positions relative to each other for landing on Mars. That is, it takes less power to travel to Mars at this time, compared to other times when Earth and Mars are in different positions in their orbits. To keep mission costs and risks as low as possible, the Mars 2020 Perseverance design is based on NASA's successful Mars Science Laboratory mission architecture, including its Curiosity rover and proven landing system.
Mars 2020 Perseverance Science
The Mars 2020 Perseverance rover explores a site likely to have been habitable. It will seek signs of past life, set aside a returnable cache with the most compelling rock core and soil samples, and demonstrate technology needed for the future human and robotic exploration of Mars. 4)
Figure 1: Evolving science strategies for Mars Explorations (image credit: NASA)
Leveraging discoveries from past Mars missions about water and habitability on Mars, the Mars 2020 Perseverance rover represents a shift toward directly seeking signs of past microbial life.
NASA's Mars Exploration Program has a long-term, systematic exploration plan for the Red Planet. Mars missions build on each other, with discoveries and innovations made by prior missions guiding what comes next. Mars missions are guided by evolving, discovery-driven science strategies that provide continuity in Mars science exploration themes.
The first framing theme guiding Mars exploration was "Follow the Water," as water is essential to habitable environments and life as we know it. It is also important to understanding the geologic and climatic history of Mars, and would likely play a role in supporting future human explorers.
With past orbiters, landers, and rovers finding evidence of water, the theme "Explore Habitability" emerged to look for additional conditions necessary to life, including chemical elements and compounds necessary for life as we know it. Findings from the Mars Science Laboratory's Curiosity rover marked a transition to the current science theme: "Seek Signs of Life."
While Curiosity is seeking evidence of habitable conditions (both past water and the chemistry needed for life), Mars 2020 Perseverance is seeking signs of past life itself in the geologic record.
The Mars 2020 Perseverance Mission Contributes to Four Science Goals for Mars Exploration
Studying Mars' Habitability, Seeking Signs of Past Microbial Life, Collecting and Caching Samples, and Preparing for Future Human Missions. The science strategy for NASA's Mars Exploration Program (MEP) is to Seek Signs of Life. The Mars 2020 Perseverance rover contributes to this strategy, as well as to the Program's four long-term science goals: 5)
• Goal 1: Determine whether life ever existed on Mars. The mission of the Mars 2020 Perseverance rover focuses on surface-based studies of the Martian environment, seeking preserved signs of biosignatures in rock samples that formed in ancient Martian environments with conditions that might have been favorable to microbial life.
- It is the first rover mission designed to seek signs of past microbial life. Earlier rovers first focused on and confirmed that Mars once had habitable conditions.
• Goal 2: Characterize the Climate of Mars. Past Martian climate conditions are a focus of the Mars 2020 Perseverance rover mission. The rover's instruments are looking for evidence of ancient habitable environments where microbial life could have existed in the past.
• Goal 3: Characterize the Geology of Mars. The Mars 2020 Perseverance rover is designed to study the rock record to reveal more about the geologic processes that created and modified the Martian crust and surface through time. Each layer of rock on the Martian surface contains a record of the environment in which it was formed. The rover seeks evidence of rocks that formed in water and that preserve evidence of organics, the chemical building blocks of life.
• Goal 4: Prepare for Human Exploration. The Mars 2020 Perseverance rover is demonstrating key technologies for using natural resources in the Martian environment for life support and fuel. It is also monitoring environmental conditions so mission planners understand better how to protect future human explorers.
- This science goal relates to national space policy for sending humans to Mars in the 2030s. Similar to the history of the exploration of Earth's moon, robotic missions to Mars provide a crucial understanding of the environment and test innovative technologies for future human exploration.
- Investments in Mars 2020 Perseverance technologies include contributions from NASA's Human Exploration and Operations (HEO) Mission Directorate and Space Technology Program (STP) as part of NASA's long-term efforts to develop future capabilities for human space exploration.
The spacecraft is the protective "spaceship" that enables the precious cargo (that is, the rover!) to travel between Earth and Mars. It is separate from the launch vehicle that carries the spacecraft and the rover outside of Earth's atmosphere and gravitational pull. The spacecraft includes the mechanical units that safely carry and maneuver the rover through the Martian atmosphere to a landing on Mars.
The three major parts of the Mars 2020 Perseverance mission spacecraft design are based on the successful Mars Science Laboratory mission:
• Cruise Stage: The configuration for travel between Earth and Mars that includes an aeroshell (backshell with heat shield) in which the rover and its landing system are enclosed.
• Entry, Descent, and Landing System: The configuration for entry into the Martian atmosphere. Includes the aeroshell, parachute, descent vehicle, and structure for a sky-crane maneuver that will lower the rover to the Martian surface on tethers.
• Rover: A wheeled vehicle with science instruments for making discoveries on the Martian surface.
Figure 2: Illustration of the Mars 2020 Perseverance spacecraft (image credit: NASA)
Technology development makes missions possible.
Each Mars mission is part of a continuing chain of innovation. Each relies on past missions for proven technologies and contributes its own innovations to future missions. This chain allows NASA to push the boundaries of what is currently possible, while still relying on proven technologies.
The Mars 2020 Perseverance mission leverages the successful architecture of NASA's Mars Science Laboratory mission by duplicating most of its entry, descent, and landing system and much of its rover design.
The mission advances several technologies, including those related to priorities in the National Research Council's 2011 Decadal Survey and for future human missions to Mars. Plans include infusing new capabilities through investments by NASA's Space Technology Program, Human Exploration and Operations Mission Directorate, and contributions from international partners.
Many innovations focus on entry, descent, and landing technologies, which help ensure precise and safe landings. They include sensors to measure the atmosphere, cameras and a microphone, and at least two key ways to reach the surface of Mars with greater accuracy and less risk (Range Trigger and Terrain-Relative Navigation).
Figure 3: The cruise stage, aeroshell, descent stage, rover and heat shield together make up the spacecraft. As the spacecraft travels down through the Martian atmosphere, certain parts fall away one by one until the rover is safely on solid Martian ground (image credit: NASA)
Figure 4: Leveraging heritage technology: Mars Rover Curiosity's sky-crane maneuver. This artist's concept shows the sky-crane maneuver during the descent of NASA's Curiosity rover to the Martian surface. The Mars mission launching in 2020 would leverage the design of this landing system and other aspects of the Mars Science Laboratory architecture (image credit: NASA/JPL-Caltech)
Mars 2020 Perseverance Rover
The Mars 2020 Perseverance rover is car-sized, about about 3 m long, 2.7 m wide, and 2.2 m tall (not including the arm). But at 1,050 kg, it weighs less than a compact car. In some sense, the rover parts are similar to what any living creature would need to keep it "alive" and able to explore. 6)
Figure 5: The Mars 2010 rover is a wheeled vehicle with science instruments for making discoveries on the Martian surface (image credit: NASA)
Figure 6: Mars 2020 Perseverance Rover build update. Tour the Spacecraft Assembly Facility at NASA's Jet Propulsion Laboratory and see the Mars 2020 Perseverance mission under construction. Project System Engineer Jennifer Trosper explains the hardware being built and tested, including the rover, descent stage, cruise stage, back shell, and heat shield (video credit: NASA/JPL-Caltech, Published on 19 February 2019)
The Mars 2020 Perseverance Rover has the following parts: 7)
• body: a structure that protects the rover's "vital organs"
• brains: computers to process information
• temperature controls: internal heaters, a layer of insulation, and more
• "neck and head": a mast for the cameras to give the rover a human-scale view
• eyes and ears : cameras and instruments that give the rover information about its environment
• arm and "hand": a way to extend its reach and collect rock samples for study
• wheels and legs: parts for mobility
• electrical power: batteries and power
• communications: antennas for "speaking" and "listening"
The Mars 2020 Perseverance rover body is based on the Mars Science Laboratory's Curiosity rover configuration. However, the Mars 2020 Perseverance rover has a new science and technology toolbox. An important difference is that this rover can sample and cache minerals. To do so, the rover has a new coring drill to collect samples. The samples are then sealed in tubes and placed on the surface of Mars. - In the future, another space mission could potentially pick up the samples and bring them to Earth for detailed analysis. 8)
Differences between Mars 2020 Perseverance and Curiosity
The large robotic arm on the front of the rover differs from Curiosity's for two main reasons:
1) Mars 2020 Perseverance will collect rock cores. Mars 2020 Perseverance needs to collect rock core samples and save them for possible future study by scientists. Curiosity studied samples collected onsite, using the rover's onboard laboratory.
2) Mars 2020 Perseverance has a larger "hand," or turret. Mars Perseverance's new functions and new science tools means it must accommodate a larger turret at the end of the robot arm. This turret has the coring drill and two science instruments, plus a color camera for close-up surface inspection and also "selfies" for engineering health checkups.
There is an internal workspace inside the rover body that is dedicated to picking up, moving and placing drill bits and sample tubes within the Sample Caching System. New motors that drive these specialized movements were needed beyond those used on rover Curiosity. The rover motor controller electronics have been modified from the Curiosity design to accommodate these motors.
New Software to Operate the Rover
Mars 2020 Perseverance will operate very differently than Curiosity. The new rover will gather 20 sealed samples of Martian rocks and soil. The samples will be set aside in a "cache" on Mars. The team is building new software to run the rover. The software will be updated with improvements throughout the mission.
Besides just managing the new sampling operations, the Mars 2020 Perseverance rover manages all of its daily activities more efficiently to balance its on-site science measurements while also collecting samples for potential future analysis. To do that, the rover's driving software - the "brains" for moving around — was changed to give Mars 2020 Perseverance greater independence than Curiosity ever had.
This allows Mars 2020 Perseverance to cover more ground without consulting controllers on Earth so frequently. Also, engineers have added a "simple planner" to the flight software. This allows more effective and autonomous use of electrical power and other rover resources. It allows the rover to shift the time of some activities to take advantage of openings in the daily operations schedule.
New Wheels for Mars 2020 Perseverance
Engineers redesigned the Mars 2020 Perseverance wheels to be more robust due to the wear and tear the Curiosity rover wheels endured while driving over sharp, pointy rocks. Mars 2020 Perseverance's wheels are narrower than Curiosity's, but bigger in diameter and made of thicker aluminum.
The combination of the larger instrument suite, new Sampling and Caching System, and modified wheels makes Mars 2020 Perseverance heavier than its predecessor, Curiosity.
The Mars 2020 Perseverance Rover's "Brains"
The computer module is called the Rover Compute Element (RCE) - there are actually two identical RCEs in the body so there is always a spare "brain." 9)
The RCE interfaces with the engineering functions of the rover over two networks which follow an aerospace industry standard designed especially for the high-reliability requirements of airplanes and spacecraft. In addition, the RCEs have a special purpose to direct interfaces with all of the rover instruments for exchange of commands and science data.
- Processor: Radiation-hardened central processor with PowerPC 750 Architecture: a BAE RAD 750. It operates at up to 200 MHz speed, 10 times the speed in Mars rovers Spirit and Opportunity's computers.
- Memory: 2 GB of flash memory (~8 times as much as Spirit or Opportunity). 256 MB of dynamic random access memory. 256 kB of electrically erasable programmable read-only memory.
The Cameras on the Mars 2020 Perseverance Rover
The rover has several cameras focused on engineering and science tasks. Some help us land on Mars, while others serve as our “eyes” on the surface to drive around. We use others to do scientific observations and aid in the collection of samples. 10)
- Main function: Take pictures, looking up and down, during descent through Martian atmosphere.
- Location: Mounted on the fore-port-side of the rover, pointing toward the ground.
- Main function: Used for driving around on Mars and for positioning the tools on the robotic arm
- Location: Various places on the rover
- Mass: < 425 grams
- Image size: 5120 x 3840 pixels
- Image resolution: 20 Mpixel
• Science Cameras The science cameras are:
- MastCam-Z is a pair of cameras that takes color images and video, three-dimensional stereo images, and has a powerful zoom lens. Like the Mastcam cameras on the Curiosity rover, Mastcam-Z on Mars 2020 Perseverance consists of two duplicate camera systems mounted on the mast that stands up from the rover deck. The cameras are next to each other and point in the same direction, providing a 3D view similar to what human eyes would see, only better. They also have a zoom function to see details of faraway targets.
- SuperCam, fires a laser at mineral targets that are beyond the reach of the rover’s robotic arm, and then analyzes the vaporized rock to reveal its elemental composition. Like the ChemCam on rover Curiosity, SuperCam fires laser pulses at pinpoint areas smaller than 1 mm from more than 7 meters away. Its camera and spectrometers then examine the rock's chemistry. It seeks organic compounds that could be related to past life on Mars. When the laser hits the rock, it creates plasma, which is an extremely hot gas made of free-floating ions and electrons. An on-board spectrograph records the spectrum of the plasma, which reveals the composition of the material.
- PIXL, uses X-ray fluorescence to identify chemical elements in target spots as small as a grain of table salt. It has a Micro-Context Camera to provide images of to correlate its elemental composition maps with visible characteristics of the target area.
- SHERLOC. Its main tools are spectrometers and a laser, but it also uses a macro camera to take extreme close-ups of the areas that are studied. This provides context so that scientists can see textures that might help tell the story of the environment in which the rock formed.
- WATSON. This camera is one of the tools on the "arm" or turret at the end of Curiosity's robotic arm. It is almost identical to the MAHLI hand-lens camera on the Curiosity rover. WATSON captures the larger context images for the very detailed information that SHERLOC collects on Martian mineral targets. WATSON provides views of the fine-scale textures and structures in Martian rocks and the surface layer of rocky debris and dust. Since WATSON can be moved around on the robotic arm, it also provides other images of rover parts and geological targets that can be used by other arm-mounted instruments. For example, it can be pointed at the oxygen-making experiment MOXIE to help monitor how much dust accumulates around the inlet that lets in Martian air for the extraction of oxygen. - A calibration target for WATSON is attached to the front of the rover body. It contains, a metric standardized bar graphic to help calibrate the instrument.
Figure 7: Overview of the Cameras on the Mars 2020 Perseverance Rover (image credit: NASA)
Mars 2020 Perseverance communications
Mars 2020 Perseverance has three antennas that serve as both its "voice" and its "ears." They are located on the rover equipment deck (its "back"). Having multiple antennas provides operational flexibility and back-up options just in case they are needed. Antennas on rover deck: 11)
UHF antenna: Most often, Mars 2020 Perseverance uses its ultra-high frequency (UHF) antenna (about 400 megahertz) to communicate with Earth through NASA's orbiters around Mars. Because the rover and orbiter antennas are within close range of each other, they act a little like walky-talkies compared to the long-range telecommunications with Earth provided by the low-gain and high-gain antennas.
It generally takes about 5 to 20 minutes for a radio signal to travel the distance between Mars and Earth, depending on planet positions. Using orbiters to relay messages is beneficial because they are much closer to the rover than the Deep Space Network (DSN) antennas on Earth. The mass- and power-constrained rover can achieve high data rates of up to 2 Mbit/s on the relatively short-distance relay link to the orbiters overhead. The orbiters then use their much larger antennas and transmitters to relay that data on the long-distance link back to Earth.
- Main function: Transmitting data to Earth through Mars Orbiters
- Radio frequency: UHF-band at ~400 MHz
- Transmission rates: Up to 2 Mbit/s on the rover-to-orbiter relay link.
X-band High-Gain Antenna: The high-gain antenna is steerable so it can point its radio beam in a specific direction. The benefit of having a steerable antenna is that the entire rover doesn't need to change position to talk to Earth, which is always moving in the Martian sky. Like turning your neck to talk to someone beside you rather than turning your entire body, the rover can save energy and keep things simple by moving only the antenna. Its high gain allows it to focus its beam, allowing higher data rates on the long link back to Earth.
- Main function: Transmitting data directly to and from Earth
- Radio frequency: X-band (7 to 8 GHz)
- Size: Hexagonally shaped, 0.3 m in diameter
- Transmission/ Reception Rates: 160/500 bit/s or faster to/from the Deep Space Network's 34 m diameter antennas or at 800/3000 bit/s or faster to/from the Deep Space Network's 70 m diameter antenna.
- Provided by: Spain.
X-band Low-Gain Antenna: Mars 2020 Perseverance uses its low-gain antenna primarily for receiving signals. This antenna can send and receive information in every direction; that is, it is "omnidirectional." The antenna transmits at low data rate to the Deep Space Network antennas on Earth. Because it doesn’t need to be pointed, it provides a robust way to always communicate with the rover.
- Main function: Receiving antenna
- Radio frequency: X-band (7 to 8 GHz)
- Reception rates: Approximately 10 bit/s or faster from the Deep Space Network's 34 m diameter antennas or approximately 30 bit/s or faster from the Deep Space Network's 70 m diameter antenna.
Mars 2020 Perseverance robotic arm
Mars 2020 Perseverance's robotic arm can move a lot like yours. It has a shoulder, elbow and wrist "joints" for maximum flexibility. The arm lets the rover work as a human geologist would: by holding and using science tools with its "hand" or turret. The rover's own "hand tools" extract cores from rocks, takes microscopic images and analyzes the elemental composition and mineral makeup of Martian rocks and soil. 12)
- Length: 2.1 m
- Degrees of freedom:
- There are five. They are made possible by tiny motors called "rotary actuators." The five degrees of freedom are known as the shoulder azimuth joint, shoulder elevation joint, elbow joint, wrist joint and turret joint.
- ”Hand” turret: At the end of the arm is the "turret." It's like a hand that carries scientific cameras, mineral and chemical analyzers for studying the past habitability of Mars, and choosing the most scientifically valuable sample to cache.
- Names of tools on the turret: SHERLOC and WATSON, PIXL, GDRT (Gaseous Dust Removal Tool), Ground Contact Sensor, Drill
- Drill: The drill is a rotary percussive drill designed to extract rock core samples from the surface of Mars.
- Drill bits: A suite of interchangeable bits: coring bits, regolith bit and an abrader.
- Main function: Assist in Mars surface investigation and sample collection
- Diameter of drilled holes: 27 mm.
The Mars 2020 Perseverance mission will gather samples from Martian rocks and soil using its drill. The rover will then store the sample cores in tubes on the Martian surface. This entire process is called "sample caching". 13)
Mars 2020 Perseverance will be the first mission to demonstrate this on Mars. It could potentially pave the way for future missions that could collect the samples and return them to Earth for intensive laboratory analysis.
The three major steps in sample handling are:
- Objectives: Collect and store a compelling set of rock and soil samples that could be returned to earth in the future.
- Witness tubes: 5 tubes
- Sample containers: 43 containers
- Samples to be collected: at least 20 samples
The Mars 2020 Perseverance rover requires electrical power to operate. Without power, the rover cannot move, use its science instruments, or communicate with Earth.
Mars 2020 Perseverance carries a radioisotope power system. This power system produces a dependable flow of electricity using the heat of plutonium's radioactive decay as its "fuel."
The power source is called the MMRTG (Multi-Mission Radioisotope Thermoelectric Generator). The MMRTG converts heat from the natural radioactive decay of plutonium into electricity. This power system charges the rover's two primary batteries. The heat from the MMRTG is also used to keep the rover's tools and systems at their correct operating temperatures.
The Department of Energy (DOE), in support of NASA, has developed several generations of such space nuclear power systems that can be used to supply electricity — and useful excess heat — for a variety of space exploration missions. The current RPS (Radioisotope Power System), called a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), was designed with the flexibility to operate on planetary bodies with atmospheres, such as at Mars, as well as in the vacuum of space. An MMRTG generates about 110 W of electrical power at launch, an increment of power that can be matched with a variety of potential mission needs. As with prior RPS, ensuring a high degree of safety is also a fundamental consideration. 14)
How RTGs work: RTGs work by converting heat from the natural decay of radioisotope materials into electricity. RTGs consist of two major elements: a heat source that contains the radioisotope fuel (mostly plutonium-238), and solid-state thermocouples that convert the plutonium’s decay heat energy to electricity.
Conversion of heat directly into electricity is a scientific principle discovered two centuries ago. German scientist Thomas Johann Seebeck observed that an electric voltage is produced when two dissimilar, electrically conductive materials are joined in a closed circuit and the two junctions are kept at different temperatures. Such pairs of junctions are called thermoelectric couples (or thermocouples).
The power output from such thermocouples is a function of the temperature of each junction and the properties of the thermoelectric materials. The thermocouples in RTGs use heat from the natural decay of the radioisotope fuel to heat the hot-side junction of the thermocouple, and the cold of space to produce a low temperature at the cold-side junction
Figure 8: Model of an MMRTG, including its internal General Purpose Heat Source (GPHS) modules (image credit: NASA)
- Objective: Provide electricity to the rover
- Location: Aft end of the rover
- Size: 64 cm in diameter by 66 cm long
- Mass: ~45 kg
- Power system: Uses 4.8 kg of plutonium dioxide as the source of the steady supply of heat
- Electrical power produced: About 110 W at launch, declining a few percent per year
- Batteries: Two lithium-ion rechargeable batteries to meet peak demands of rover activities when the demand temporarily exceeds the MMRTG's steady electrical output levels.
- Reliability: The electrical power system on the Mars 2020 Perseverance rover is just like the one used on the Mars Science Laboratory Curiosity rover. NASA has used similar power systems reliably for decades, including the Apollo missions to the Moon, the Viking missions to Mars, and on spacecraft that flew to the outer planets and Pluto, including the Pioneer, Voyager, Ulysses, Galileo, Cassini, and New Horizons missions.
- Safety: Built with several layers of rugged protective material to contain its fuel in a wide range of potential launch accidents, verified through impact testing. The heat source plutonium is manufactured in a ceramic form, which helps it avoid being a significant health hazard unless broken into very fine pieces or vaporized, and then inhaled or swallowed. In the unlikely event of a Mars 2020 Perseverance launch accident, those who might be exposed could receive an average dose of 15-60 millirem. A resident of the United States receives, on average, 310 millirem of radiation each year from natural sources, such as radon and cosmic rays from space.
This power system provides several advantages:
• The 14-year operational lifetime of an MMRTG provides significant reserve for Mars 2020 Perseverance prime mission duration of 1.5 Mars years (three Earth years)
• It gives the rover greater mobility over a large range of latitudes and altitudes
• It allows scientists to maximize the capabilities of the rover's science instruments
• It provides engineers with a lot of flexibility in operating the rover (e.g., day and night, and through the winter season).
Note: As of July 2020, the previously single large Mars2020 file has been split into three files, to make the file handling manageable for all parties concerned, in particular for the user community. The chapter ”Development Status” has so high-resolution imagery, that it had to be split into two files.
• This file covers the Mars 2020 Perseverance mission and its imagery without the Development Status
Launch: The Mars 2020 Perseverance mission was launched from the Cape Canaveral Air Force Station (SLC-41) in Florida on July 30, 2020 (11:50 UTC) on a two-stage Atlas V-541 launch vehicle, provided by ULA (United Launch Alliance). The mission will land at the Jezero Crater on 18 February 2021. 15) 16)
- "With the launch of Perseverance, we begin another historic mission of exploration," said NASA Administrator Jim Bridenstine. "This amazing explorer's journey has already required the very best from all of us to get it to launch through these challenging times. Now we can look forward to its incredible science and to bringing samples of Mars home even as we advance human missions to the Red Planet. As a mission, as an agency, and as a country, we will persevere."
- The ULA Atlas V's Centaur upper stage initially placed the Mars 2020 spacecraft into a parking orbit around Earth. The engine fired for a second time and the spacecraft separated from the Centaur as expected. Navigation data indicate the spacecraft is perfectly on course to Mars.
Figure 9: A United Launch Alliance Atlas V rocket with NASA’s Mars 2020 Perseverance rover onboard launches from Space Launch Complex 41, Thursday, July 30, 2020, at Cape Canaveral Air Force Station in Florida. The Perseverance rover is part of NASA’s Mars Exploration Program, a long-term effort of robotic exploration of the Red Planet (image credit: NASA, Joel Kowsky)
The Mars 2020 spacecraft separated from the rocket’s Centaur upper stage 57 minutes after liftoff and five minutes after a second burn of the Centaur that placed the spacecraft on a trajectory toward Mars.
Perseverance is based on the Curiosity rover that has been on Mars since August 2012, but with a number of modifications. “We’re carrying about 50% more surface payload than Curiosity did, and that was by far the most complex thing we had ever done up until that time,” Matt Wallace, Mars 2020 deputy program manager, said at a pre-launch briefing.
Much of that additional payload, and complexity, is for the rover’s system to collect samples of Martian rocks. The rover will cache up to three dozen samples in tubes for return to Earth by two later missions that NASA is developing in cooperation with the European Space Agency for launch in 2026.
The rover includes several other upgrades. A terrain relative navigation system will compare images taken by the spacecraft during its descent to the Martian surface with maps on the spacecraft, and direct the spacecraft accordingly to enable a pinpoint landing. Engineers also upgraded the rover’s wheels after rocks damaged the wheels on Curiosity.
In addition to its payload of sample collection equipment and scientific experiments, Perseverance is carrying a small helicopter called Ingenuity. The 1.8-kilogram helicopter, stored on the rover’s belly pan, will be released after landing for a series of flight tests.
“We as human beings have never flown a rotorcraft outside of our Earth’s atmosphere, so this will be very much a Wright Brothers moment,” said Mimi Aung, Ingenuity Mars Helicopter project manager at JPL, during a pre-launch briefing. Engineers hope to perform several flights of Ingenuity over 30 days to test its performance.
Aung compared Ingenuity to Sojourner, the small rover flown on the Mars Pathfinder lander mission in 1997, paving the way for larger rovers like Perseverance. “This Mars helicopter, Ingenuity, could lead to the opening of a whole new way to explore,” she said.
• October 12, 2021: NASA, along with the European Space Agency, is developing a campaign to return the Martian samples to Earth. 17)
- On Sept. 1, NASA’s Perseverance rover unfurled its arm, placed a drill bit at the Martian surface, and drilled about 2 inches (6 cm), down to extract a rock core. The rover later sealed the rock core in its tube. This historic event marked the first time a spacecraft packed up a rock sample from another planet that could be returned to Earth by future spacecraft.
Figure 10: This composite of two images shows the hole drilled by NASA's Perseverance rover during its second sample-collection attempt. The images, which were obtained by one of the rover's navigation cameras on Sept. 1, 2021 (the 190th sol, or Martian day, of the mission), were taken in the "Crater Floor Fractured Rough" geologic unit in Mars' Jezero Crater. The team nicknamed the rock "Rochette" for reference and the spot on the rock where the sample was cored "Montdenier." (image credit: NASA/JPL-Caltech)
- Mars Sample Return is a multi-mission campaign designed to retrieve the cores Perseverance will collect over the next several years. Currently in the concept design and technology development phase, the campaign is one of the most ambitious endeavors in spaceflight history, involving multiple spacecraft, multiple launches, and dozens of government agencies.
- “Returning a sample from Mars has been a priority for the planetary science community since the 1980s, and the potential opportunity to finally realize this goal has unleashed a torrent of creativity,” said Michael Meyer, lead scientist for NASA’s Mars Exploration Program based at NASA Headquarters in Washington.
Figure 11: The first cored sample of Mars rock is visible (at center) inside a titanium sample collection tube in this from the Sampling and Caching System Camera (known as CacheCam) of NASA's Perseverance rover. The image was taken on Sept. 6, 2021 (the 194th sol, or Martian day, of the mission), prior to the system attaching and sealing a metal cap onto the tube (video credit: NASA/JPL-Caltech)
- The benefit of analyzing samples back on Earth — rather than assigning the task to a rover on the Martian surface — is that scientists can use many kinds of cutting-edge lab technologies that are too big and too complex to send to Mars. And they can do analyses much faster in the lab while providing far more information on whether life ever existed on Mars.
- “I have dreamed of having Mars samples to analyze since I was a graduate student,” said Meenakshi Wadhwa, principal scientist for the Mars Sample Return program, which is managed by NASA’s Jet Propulsion Laboratory in Southern California. “The collection of these well-documented samples will eventually allow us to analyze them in the best laboratories here on Earth once they are returned.”
- Mars Sample Return would involve several firsts aimed at settling an open question: Has life taken root anywhere in the solar system besides Earth? “I’ve been working my whole career for the opportunity to answer this question,” said Daniel Glavin, an astrobiologist from NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Glavin is helping design systems to protect the Martian samples from contamination throughout their journey from Mars to Earth.
Figure 12: Collecting samples from Mars and bringing them back to Earth will be a historic undertaking that started with the launch of NASA’s Perseverance rover on July 30, 2020. Perseverance collected its first rock core samples in September 2021. The rover will leave them on Mars for a future mission to retrieve and return to Earth. NASA and the European Space Agency (ESA) are solidifying concepts for this proposed Mars Sample Return campaign. The current concept includes a lander, a fetch rover, an ascent vehicle to launch the sample container to Martian orbit, and a retrieval spacecraft with a payload for capturing and containing the samples and then sending them back to Earth to land in an unpopulated area (video credits: Animation credit: NASA/JPL-Caltech, ESA, NASA/GSFC and NASA/GRC. Technical assistance: James Tralie, NASA Goddard. Music credit: Axel Coon and Ralf Goebel of Universal Production Music)
- Being developed in collaboration with ESA (European Space Agency), Mars Sample Return would require autonomously launching a rocket full of precious extraterrestrial cargo from the surface of Mars. Engineers would need to ensure that the rocket’s trajectory aligns with that of a spacecraft orbiting Mars so the sample capsule could be transferred to the orbiter. The orbiter would then return the sample capsule to Earth, where scientists would be waiting to safely contain it prior to transport to a secure biohazard facility, one that is under development now.
- Before bringing Martian samples to Earth, scientists and engineers must overcome several challenges. Here’s a look at one:
Protecting Earth From Mars
- Keeping samples chemically pristine for rigorous study on Earth while subjecting their storage container to extreme sterilization measures to ensure nothing hazardous is delivered to Earth is a task that makes Mars Sample Return truly unprecedented.
- Billions of years ago the Red Planet may have had a cozy environment for life that thrives in warm and wet conditions. However, it’s highly unlikely that NASA will bring back samples with living Martian organisms, based on decades of data from orbiters, landers, and rovers at Mars. Instead, scientists are hoping to find fossilized organic matter or other signs of ancient microbial life.
- Despite the low risk of bringing anything alive to Earth, an abundance of caution is driving NASA to take significant measures to ensure the Martian samples remain securely sealed throughout their journey. After collecting rock cores throughout Jezero Crater and placing them inside tubes made mostly of titanium, one of the world’s strongest metals, Perseverance tightly seals the tubes to prevent the inadvertent release of even the smallest particle. The tubes are then stored in the rover’s belly until NASA decides on the time and place to drop them on the Martian surface.
- A sample return campaign would include an ESA sample fetch rover that would launch from Earth later this decade to pick up these samples collected by Perseverance. Engineers at NASA’s Glenn Research Center in Cleveland, Ohio, are designing the wheels for the fetch rover. The rover would transfer samples to a lander, being developed at JPL. A robotic arm on the lander would pack the samples into the tip of a rocket that is being designed by NASA’s Marshall Space Flight Center in Huntsville, Alabama.
- The rocket would deliver the sample capsule to Martian orbit, where an ESA orbiter would be waiting to receive it. Inside the orbiter, the capsule would be prepared for delivery to Earth by a payload being developed by a team led by NASA Goddard. This preparation would include sealing the sample capsule inside a clean container to trap any Martian material inside, sterilizing the seal, and using a robotic arm being developed at Goddard to place the sealed container into an Earth-entry capsule before the return trip to Earth.
Figure 13: This illustration shows a concept for a set of future robots working together to ferry back samples from the surface of Mars collected by NASA's Mars Perseverance rover. NASA and the European Space Agency (ESA) are solidifying concepts for a Mars sample return mission that would seek to take the samples of Martian rocks and other materials being collected and stored in sealed tubes by NASA's Mars Perseverance rover and return the sealed tubes to Earth (image credit: NASA/ESA/JPL-Caltech)
- One of the primary tasks for NASA engineers is figuring out how to seal and sterilize the sample container without obliterating important chemical signatures in the rock cores inside. Among the techniques the team is currently testing is brazing, which involves melting a metal alloy into a liquid that essentially glues metal together. Brazing can seal the sample container at a temperature high enough to sterilize any dust that might remain in the seam.
- “Among our biggest technical challenges right now is that inches away from metal that’s melting at about 1,000ºF (or 538º C) we have to keep these extraordinary Mars samples below the hottest temperature they might have experienced on Mars, which is about 86ºF (30ºC ),” said Brendan Feehan, the Goddard systems engineer for the system that will capture, contain, and deliver the samples to Earth aboard ESA’s orbiter. “Initial results from the testing of our brazing solution have affirmed that we’re on the right path.”
- Careful design by Feehan and his colleagues would allow heat to be applied only to where it is needed for brazing, limiting heat flow to the samples. Additionally, engineers could insulate the samples in a material that will absorb the heat and then release it very slowly, or they could install conductors that direct the heat away from the samples.
- Whatever technique the team develops will be critical not only for the Martian samples, Glavin said, but for future sample-return missions to Europa or Enceladus, “where we could collect and return fresh ocean plume samples that could contain living extraterrestrial organisms. So we need to figure this out.”
- NASA’s rigorous efforts to eliminate risk of harmful contamination of Earth date to the international Outer Space Treaty of 1967, which calls on nations to prevent contaminating celestial bodies with organisms from Earth, and to prevent contamination of Earth through returned samples. To safely return a Martian sample to Earth, NASA is partnering not only with ESA, but also with at least 19 U.S. government departments and agencies, including the U.S. Centers for Disease Control and Prevention and the U.S. Department of Homeland Security.
• October 7, 2020: A new paper from the science team of NASA’s Perseverance Mars rover details how the hydrological cycle of the now-dry lake at Jezero Crater is more complicated and intriguing than originally thought. The findings are based on detailed imaging the rover provided of long, steep slopes called escarpments, or scarps in the delta, which formed from sediment accumulating at the mouth of an ancient river that long ago fed the crater’s lake. 18)
- Pictures from NASA’s latest six-wheeler on the Red Planet suggest the area’s history experienced significant flooding events.
Figure 14: The escarpment the science team refers to as “Scarp a” is seen in this image captured by Perseverance rover’s Mastcam-Z instrument on Apr. 17, 2021 (image credit: NASA/JPL-Caltech/ASU/MSSS)
- The images reveal that billions of years ago, when Mars had an atmosphere thick enough to support water flowing across its surface, Jezero’s fan-shaped river delta experienced late-stage flooding events that carried rocks and debris into it from the highlands well outside the crater.
Figure 15: This image of “Kodiak” – one remnant of the fan-shaped deposit of sediments inside Mars’ Jezero Crater known as the delta – was taken by Perseverance’s Mastcam-Z instrument on Feb. 22, 2021 (image credit: NASA/JPL-Caltech/ASU/MSSS)
- Taken by the rover’s left and right Mastcam-Z cameras as well as its Remote Micro-Imager, or RMI (part of the SuperCam instrument), they also provide insight into where the rover could best hunt for rock and sediment samples, including those that may contain organic compounds and other evidence that life once existed there.
- The rover team has long planned to visit the delta because of its potential for harboring signs of ancient microbial life. One of the mission’s primary goals is to collect samples that could be brought to Earth by the multi-mission Mars Sample Return effort, enabling scientists to analyze the material with powerful lab equipment too large to bring to Mars.
Perseverance’s ‘Kodiak’ Moment
- At the time the images were taken, the scarps were to the northwest of the rover and about 1.2 miles (2.2 km) away. Southwest of the rover, and at about the same distance, lies another prominent rock outcrop the team calls “Kodiak.” In its ancient past, Kodiak was at the southern edge of the delta, which would have been an intact geologic structure at the time.
- Prior to Perseverance’s arrival, Kodiak had been imaged only from orbit. From the surface, the rover’s Mastcam-Z and RMI images revealed for the first time the stratigraphy – the order and position of rock layers, which provides information about the relative timing of geological deposits – along Kodiak’s eastern face. The inclined and horizontal layering there is what a geologist would expect to see in a river delta on Earth.
- “Never before has such well-preserved stratigraphy been visible on Mars,” said Nicolas Mangold, a Perseverance scientist from the Laboratoire de Planétologie et Géodynamique in Nantes, France, and lead author of the paper. “This is the key observation that enables us to once and for all confirm the presence of a lake and river delta at Jezero. Getting a better understanding of the hydrology months in advance of our arrival at the delta is going to pay big dividends down the road.”
- While the Kodiak results are significant, it is the tale told by the images of the scarps to the northeast that came as the greatest surprise to the rover science team.
Figure 16: The top mosaic of Jezero Crater’s river delta was stitched together from multiple images taken by the Mastcam-Z instrument aboard NASA’s Perseverance rover on Apr. 17, 2021. The bottom annotated image highlights the location of four prominent long, steep slopes known as escarpments, or scarps (image credit: NASA/JPL-Caltech/ASU/MSSS)
- Imagery of those scarps showed layering similar to Kodiak’s on their lower halves. But farther up each of their steep walls and on top, Mastcam-Z and RMI captured stones and boulders.
- “We saw distinct layers in the scarps containing boulders up to 5 feet [1.5 m] across that we knew had no business being there,” said Mangold.
- Those layers mean the slow, meandering waterway that fed the delta must have been transformed by later, fast-moving flash floods. Mangold and the science team estimate that a torrent of water needed to transport the boulders – some for tens of miles – would have to travel at speeds ranging from 4 to 20 mph (6 to 30 km/h).
- “These results also have an impact on the strategy for the selection of rocks for sampling,” said Sanjeev Gupta, a Perseverance scientist from Imperial College, London, and a co-author of the paper. “The finest-grained material at the bottom of the delta probably contains our best bet for finding evidence of organics and biosignatures. And the boulders at the top will enable us to sample old pieces of crustal rocks. Both are main objectives for sampling and caching rocks before Mars Sample Return.”
A Lake of Changing Depths
- Early in the history of the Jezero Crater’s former lake, its levels are thought to have been high enough to crest the crater’s eastern rim, where orbital imagery shows the remains of an outflow river channel. The new paper adds to this thinking, describing the size of Jezero’s lake fluctuating greatly over time, its water level rising and falling by tens of yards before the body of water eventually disappeared altogether.
- While it’s unknown if these swings in the water level resulted from flooding or more gradual environmental changes, the science team has determined that they occurred later in the Jezero delta’s history, when lake levels were at least 330 feet (100 meters) below the lake’s highest level. And the team is looking forward to making more insights in the future: The delta will be the starting point for the rover team’s upcoming second science campaign next year.
- “A better understanding of Jezero’s delta is a key to understanding the change in hydrology for the area,” said Gupta, “and it could potentially provide valuable insights into why the entire planet dried out.”
• September 10, 2021: NASA’s Perseverance Mars rover successfully collected its first pair of rock samples, and scientists already are gaining new insights into the region. After collecting its first sample, named “Montdenier,” Sept. 6, the team collected a second, “Montagnac,” from the same rock Sept. 8. 20)
- Analysis of the rocks from which the Montdenier and Montagnac samples were taken and from the rover’s previous sampling attempt may help the science team piece together the timeline of the area’s past, which was marked by volcanic activity and periods of persistent water.
- “It looks like our first rocks reveal a potentially habitable sustained environment,” said Ken Farley of Caltech, project scientist for the mission, which is led by NASA’s Jet Propulsion Laboratory in Southern California. “It’s a big deal that the water was there a long time.”
- The rock that provided the mission’s first core samples is basaltic in composition and may be the product of lava flows. The presence of crystalline minerals in volcanic rocks is especially helpful in radiometric dating. The volcanic origin of the rock could help scientists accurately date when it formed. Each sample can serve as part of a larger chronological puzzle; put them in the right order, and scientists have a timeline of the most important events in the crater’s history. Some of those events include the formation of Jezero Crater, the emergence and disappearance of Jezero’s lake, and changes to the planet’s climate in the ancient past.
Figure 17: Two holes are visible in the rock, nicknamed “Rochette,” from which NASA’s Perseverance rover obtained its first core samples. The rover drilled the hole on the left, called “Montagnac,” on Sept. 7, and the hole on the right, known as “Montdenier,” on Sept. 1. Below it is a round spot the rover abraded (image credit: NASA/JPL-Caltech)
Figure 18: This mosaic image (composed of multiple individual images taken by NASA's Perseverance rover) shows a rock outcrop in the area nicknamed "Citadelle" on the floor of Mars' Jezero Crater (image credit: NASA/JPL-Caltech/ASU/MSSS)
- What’s more, salts have been spied within these rocks. These salts may have formed when groundwater flowed through and altered the original minerals in the rock, or more likely when liquid water evaporated, leaving the salts. The salt minerals in these first two rock cores may also have trapped tiny bubbles of ancient Martian water. If present, they could serve as microscopic time capsules, offering clues about the ancient climate and habitability of Mars. Salt minerals are also well-known on Earth for their ability to preserve signs of ancient life.
- The Perseverance science team already knew a lake once filled the crater; for how long has been more uncertain. The scientists couldn’t dismiss the possibility that Jezero’s lake was a “flash in the pan”: Floodwaters could have rapidly filled the impact crater and dried up in the space of 50 years, for example.
- But the level of alteration that scientists see in the rock that provided the core samples – as well as in the rock the team targeted on their first sample-acquisition attempt – suggests that groundwater was present for a long time.
- This groundwater could have been related to the lake that was once in Jezero, or it could have traveled through the rocks long after the lake had dried up. Though scientists still can’t say whether any of the water that altered these rocks was present for tens of thousands or for millions of years, they feel more certain that it was there for long enough to make the area more welcoming to microscopic life in the past.
- “These samples have high value for future laboratory analysis back on Earth,” said Mitch Schulte of NASA Headquarters, the mission’s program scientist. “One day, we may be able to work out the sequence and timing of the environmental conditions that this rock’s minerals represent. This will help answer the big-picture science question of the history and stability of liquid water on Mars.”
Next Stop, ‘South Séítah’
- Perseverance is currently searching the crater floor for samples that can be brought back to Earth to answer profound questions about Mars’ history. Promising samples are sealed in titanium tubes the rover carries in its chassis, where they’ll be stored until Perseverance drops them to be retrieved by a future mission. Perseverance will likely create multiple “depots” later in the mission, where it will drop off samples for a future mission to bring to Earth. Having one or more depots increases the likelihood that especially valuable samples will be accessible for retrieval to Earth.
- Perseverance’s next likely sample site is just 200 meters away in “South Séítah,” a series of ridges covered by sand dunes, boulders, and rock shards that Farley likens to “broken dinner plates.”
- The rover’s recent drill sample represents what is likely one of the youngest rock layers that can be found on Jezero Crater’s floor. South Séítah, on the other hand, is likely older, and will provide the science team a better timeline to understand events that shaped the crater floor, including its lake.
- By the start of October, all Mars missions will be standing down from commanding their spacecraft for several weeks, a protective measure during a period called Mars solar conjunction. Perseverance isn’t likely to drill in South Séítah until sometime after that period.