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At least 127 records · Page 7

Understanding Sampling Hardware Cleanliness from Perseverance Lessons Learned, and Forward Approach to Biosignature Missions

The search for biosignatures on other solar system bodies drives the scientific objectives of many ongoing and proposed exploration missions, including the Europa Lander mission concept.[1] The detection of trace and unfamiliar biosignatures in extreme environments necessitates state-of-the-art scientific instrumentation with extraordinary sensitivity – and often, extraordinary susceptibility to terrestrial and spacecraft self-induced contamination vectors.[2] While instruments can be carefully designed to operate remotely at high performance, in situ scientific measurements can only analyze the samples they’re given: samples or sample handling hardware that have been inadvertently tainted by outgassed organic molecules, thruster plume effluents, or other common sources of spacecraft contamination may yield ambiguous or false results. Maintaining and verifying the purity of collected samples and the cleanliness of sample handling hardware throughout the lifecycle of biosignature detection missions like Europa Lander is a primary responsibility of the Contamination Control group at JPL.

Alred, John↗

Robotics Verification and Validation Strategies for Perseverance Rover Sampling and Caching

The Mars 2020 Sampling and Caching Subsystem(SCS) is the most complex robotic system ever fielded on a MarsRover. It includes a 5 degree-of-freedom Robotic Arm, coringdrill, gas Dust Removal Tool, interfaces for two turret-mountedinstruments, and an Adaptive Caching Assembly (ACA). TheACA is itself a complex robotic system, containing hardware tosupport docking and bit exchange, a 3 degree-of-freedomSample Handling Assembly for manipulating sample tubes,storage for several drill bits and sample tubes, and mechanismsto support observing and sealing samples collected by the drill.To successfully verify and validate the SCS hardware andsoftware and its integration with the Mars 2020 flight systemseveral key strategies were employed.The SCS Verification and Validation (V&V) program utilizedmultiple test venues with tiered levels of fidelity. These includedsimulation and visualization software environments, low fidelitydevelopment testbeds, testbeds with high fidelity SCS hardwareand commercial off-the shelf avionics, integrated systemtestbeds with flight-like avionics, and environmental testbedscapable of simulating Martian surface temperature andpressure. Multiple units of each SCS hardware componentmoved fluidly between test venues to accomplish myriadstandalone and coordinated test objectives. Test preparationand executions were performed by a diverse team of engineerswith training and technical ownership tailored for individualexperience and role. Despite significant differences between testvenues, the SCS V&V team established efficient and consistentprocesses and tools for procedure development, test execution,and data review that enabled personnel, as well as technicalproducts such as sequences and parameter configurations, toflow between venues effectively. A series of benchmark testsprovided evidence of performance consistency as elements weretransferred between venues and as system capability evolved.This paper provides an overview of the SCS V&V program andexplores several overarching strategies that enabled successfuloperation in the face of unprecedented complexity. Keyoutcomes of the SCS validation effort are summarized, alongwith lessons learned and beneficial integrations of validationtool and process innovations into Mars surface operations.

Brooks, Sawyer↗

How to Build a Rover: An Overview of the Mars 2020 Mission’s Vehicle System Testbed

While NASA’s Mars rover Perseverance continues to make groundbreaking achievements on the Red Planet, its twin is hard at work here on Earth. The Operational Perseverance Twin for the Integration of Mechanisms and Instruments Sent to Mars, or OPTIMISM, is the Mars 2020 Vehicle System Testbed (VSTB) rover operated by NASA Jet Propulsion Laboratory (JPL) in Pasadena, California. OPTIMISM’s home is the JPL Mars Yard; an outdoor field with red soil that simulates the terrain encountered by Perseverance. The VSTB is a full-scale engineering model of the flight rover, serving a number of functions to ensure mission operations can continue smoothly and on schedule. The VSTB possesses instrumentation, computers, mechanisms, cameras, and a Mobility subsystem that are nearly identical to its extraterrestrial twin. Its high fidelity allows the rover to be a highly effective tool to fully test system functionality and performance prior to commanding the flight rover. The early stages of building OPTIMISM began a few months prior to Perseverance departing JPL for Cape Canaveral, FL in early 2020. Electrical integration of the flight system avionics, and compatibility checkouts of the electrical ground support equipment ensured that the foundation of the electrical system was operational and in place. Next, the internal harnessing was installed and compatibility checks of the rover instrumentation and mechanisms were performed to confirm the system was prepared for full buildup. Finally, mechanical assembly of the rover chassis with its external components completed the integration of the system before it was moved to the Mars Yard for its initial phase of testing to perform verification & validation (V&V) of the Mobility subsystem requirements. By the time Perseverance landed at Jezero Crater in February 2021, the first phase of VSTB operations was underway. Surface guidance, navigation, and control (SGNC) testing for the Mobility subsystem ensured functionality and performance requirements were met for various capabilities such as visual odometry (VO), mapping, and automatic navigation (AutoNav). Subsequent integration of the robotic arm (RA) onto the VSTB enabled the V&V campaign for surface sampling operations (SSO) to commence. As the mission’s engineering operations (EO) have gotten underway, the VSTB has been utilized for an array of purposes including troubleshooting software anomalies, and performing dry-runs for first time activities (FTAs) prior to sending the commands to Perseverance. OPTIMISM will continue to serve mission critical functions as long as Perseverance is roving the Red Planet.

Rojas, Jose Trujillo↗

NASA-ESA Mars Sample Return Program

NASA's Perseverance mission arrived at Jezero Crater on Mars in February 2021 and began scientific studies and acquisition of Martian samples for return to Earth by future missions, consistent with the recommendations of the U.S. science community in the previous Planetary Science Decadal Survey. NASA and ESA have established a joint Mars Sample Return (MSR) program to safely deliver these samples back to Earth, allowing researchers to use advanced scientific instrumentation that cannot be transported on robotic spacecraft and enable future studies of carefully curated samples using capabilities that have not yet been developed. The MSR architecture consists of two flight elements to follow Perseverance, the NASA-led Sample Retrieval Lander (SRL) and the ESA-led Earth Return Orbiter (ERO). The ERO is designed to orbit Mars and provide relay services for the SRL, including its ESA Sample Fetch Rover (SFR) and the NASA Mars Ascent Vehicle (MAV). The SRL deploys the SFR to retrieve Martian samples cached by the Perseverance rover and then returns the samples to the Orbiting Sample container (OS) on board the MAV using the ESA Sample Transfer Arm (STA). Independently, Perseverance could also deliver samples retained onboard to the OS. The MAV would launch and release the OS into low Mars orbit for rendezvous with the ERO. Upon successful capture of the OS in the ERO’s primary payload, the NASA Capture/Containment Return System (CCRS), the OS would be safely contained and loaded into the Earth Entry System (EES). The ERO will leave Mars orbit and release the EES on Earth approach on a ballistic reentry trajectory through the Earth's atmosphere for landing in the United States. Following return of the samples to Earth, the samples would be protected, preserved, assessed, curated, and made available to the international science community for scientific research and analysis. The NASA SRL and ESA ERO missions are expected to launch as early as 2026, with the return of Martian samples to Earth as early as 2031. MSR’s primary objective is the return of scientifically selected Mars samples for detailed investigation in terrestrial laboratories. The mission would also further inform the design of future human missions. The Mars Sample Return campaign is underway with the successful collection of several scientifically selected samples in Jezero Crater. The MSR Program is working towards a confirmation review in 2023 for the remaining flight elements.

Mars↗

New Rover Conops with High-Performance Onboard Computing: Give Up Raw Data to Reduce Ops Cost and Do More Science

A major portion of time during the tactical operation of Mars rovers is spent for selecting, prioritizing, and coordinating sciences and engineering activities such that they fit within resource constraints, including the downlink data volume, energy, and time. In particular, the downlink data volume constraint is getting particularly tighter in recent missions because modern instruments produce increasingly high data volume while the communication bandwidth is essentially bounded by the law of physics. Tactical operation would be substantially simplified, hence the operation cost could be reduced, if the data volume constraint is relaxed or even removed. In this abstract, we propose a new operation paradigm for achieving this goal. The key observation is that, both in science and engineering applications, the bit size of raw data is typically much greater than the volume of processed information that is needed for scientific or engineering analysis. For example, a full-resolution image from Mastcam-Z, the main science camera on Perseverance, is about 700 kB in volume and we downlinked 29,685 images up to Sol 243, totaling ~20 GB of data. But of course, scientists do not use every pixel of these images; what they really look for in the images are geological features, typically represented by specific geometric configurations or textures. An end product after processing hundreds of Mascam-Z images could be a single geological map summarizing the spatial distribution of the features. For another example, a 100-meter drive of Perseverance produces 7-12 MB of drive telemetry, which records every detail of the rover's motion at 8 Hz, including position, attitude, steering angles, encoder readings, motor currents and many other information. But what the ground engineers eventually pay attention to is the signs of anomaly, such as excessive motor currents or high slip; if a drive is nominal, the vast majority of this data is unused. What if, then, we process the raw data onboard and only downlink the processed data that is relevant to scientific or engineering analyses, such as a list of detected science features (with cropped images) or a list of potential signs of anomaly while driving? A major roadblock for such onboard, high-level information processing has been the onboard computational resource. RAD750, the main onboard computer of Perseverance, is obviously not sufficient for performing complex image or signal processing such as object detection, semantic segmentation, or anomaly detection. Interestingly, RAD750 is not the best processor that Perseverance has; Qualcomm's Snapdragon 801, a modern mobile processor, is on her Heli Base Station, a device for communicating with Mars Helicopter Ingenuity; also, Intel's Atom E3845 processors are on engineering cameras. In the reminder of this paper, we will introduce two particular uses cases of these high-performance co-processors (meaning auxiliary CPU, GPU, or other types of processors that are separate from the main processor that runs the main flight software) for lowering operation cost and accommodating more science activities for a given communication constraint.

Didier, A.↗

What Are the Olivine-Rich Boulders in the Upper Fan and Margin Unit at Jezero Crater, Mars?

Since February 2021, the Perseverance rover has explored Jezero Crater in the Nili Fossae region of Mars which hosts large outcrops of a regional olivine-carbonate unit. In the crater floor, Perseverance investigated two igneous formations: Máaz, composed of basaltic lava and/or pyroclastic flows, and Séítah, an olivine-rich cumulate] below Máaz. Then, Perseverance explored the western fan composed by diverse sedimentary rocks of variable composition, but often containing olivine On the upper fan and margin unit, Perseverance encountered number of centimetric to metric boulder rocks. Two main types of boulders were identified based on texture and composition: the olivine-rich and pyroxene-bearing boulders. Here, we use SuperCam data to describe the texture, geochemistry and mineralogy of the olivine-rich boulders. Then, we discuss their possible petrological origin and some possible implications for the regional Nili Fossae olivine-carbonate unit.

Mars 2020↗

Sedimentology and Stratigraphy of the Lower Delta Sequence, Jezero Crater, Mars.

In April 2022, the Mars 2020 Perseverance rover arrived at the base of the ancient delta in Jezero crater after completing the first year of its mission exploring and sampling aqueously altered igneous rocks of the present-day crater floor. Perseverance then spent ~200 sols exploring the lower ~25 m of rock exposed within the eastern scarp of the Jezero delta, a sedimentary sequence informally named the ‘Shenandoah’ formation. This study describes the sedimentology and stratigraphy of the Shenandoah formation explored by Perseverance at two sections—'Cape Nukshak’ and ‘Hawksbill Gap’—including a description, interpretation, and depositional framework for the facies that comprise it.

K. M. Stack↗

Sampling the Margin Unit of Jezero Crater, Mars for Future Mars Sample Return

Mars 2020 Perseverance rover is currently exploring Jezero crater, which contains an ancient lake-delta system with a high potential for past habitability. One of Perseverance’s primary science goals is to collect a set of scientifically return-worthy samples for return to Earth (Mars Sample Return; MSR). Between February 2021 and December 2023, Perseverance has sealed 23 tubes containing 20 rock cores, 2 regolith samples and one atmosphere sample. All rock and regolith samples are accompanied by a set of observations (Sample Threshold Observation Protocol, the STOP List) performed on abrasion patches or regolith near each sample collection site. These observations are documented in the Initial Reports and the Sample Dossier (https://pds-geosciences.wustl.edu/missions/mars2020/returned_sample_science.htm). Here we provide an overview of the samples collected during the Margin campaign. The Margin unit is situated interior and adjacent to the western crater rim and exhibits a strong carbonate signal from orbital reflectance spectroscopy. Stratigraphically the unit lies beneath the previously explored curvilinear and blocky units of the fan top and is therefore older than those units. Based on its position near the crater rim and the strong carbonate detections it has been proposed to be a shoreline deposit with possible lacustrine carbonates. Alternative hypotheses include pyroclastic, fluviolacustrine and aeolian deposits. Based on rover observations a lacustrine shoreline deposit seems most likely. The planning of the Margin campaign took place during the summer of 2023, and 3-5 samples were baselined to be collected. Exploration of the Margin unit began in September 2023 and so far, two samples have been collected: the Pelican Point core at the Hans Amundsen Memorial Workspace in the Mandu Wall region , and the Lefroy Bay core at Lake Newell in the Turquoise Bay region (Fig. 1). The associated abrasion patches are Amherst Point (Pelican Point) and Bills Bay (Lefroy Bay) . Mandu Wall is interpreted to be stratigraphically lower than Turquoise Bay based on topography.

Mars sample return↗

Scientific Value of Including an Atmospheric Sample as Part of Mars Sample Return (MSR)

The Perseverance rover is meant to collect samples of the martian surface for eventual return to Earth. The headspace gas present over the solid samples within the sample tubes will be of significant scientific interest for what it reveals about the interactions of the solid samples with the trapped atmosphere and for what it will reveal about the martian atmosphere itself. However, establishing the composition of the martian atmosphere will require other dedicated samples. The headspace gas as the sole atmospheric sample is problematic for many reasons. The quantity of gas present within the sample tube volume is insufficient for many investigations, and there will be exchange between solid samples, headspace gas, and tube walls. Importantly, the sample tube materials and preparation were not designed for optimal Mars atmospheric gas collection and storage as they were not sent to Mars in a degassed evacuated state and have been exposed to both Earth's and Mars' atmospheres. Additionally, there is a risk of unconstrained seal leakage in transit back to Earth, which would allow fractionation of the sample (leak-out) and contamination (leak-in). The science return can be improved significantly (and, in some cases, dramatically) by adding one or more of several strategies listed here in increasing order of effectiveness and difficulty of implementation: (1) Having Perseverance collect a gas sample in an empty sample tube, (2) Collecting gas in a newly-designed, valved, sample-tube-sized vessel that is flown on either the Sample Fetch Rover (SFR) or the Sample Retrieval Lander (SRL), (3) Adding a larger (50-100 cc) dedicated gas sampling volume to the Orbiting Sample container (OS), (4) Adding a larger (50-100 cc) dedicated gas sampling volume to the OS that can be filled with compressed martian atmosphere.

Timothy D. Swindle↗

MSR Science Planning Group 2 (MSPG2): Science & Curation Considerations for Time Sensitive Measurements That Should be Performed in Containment

The Perseverance rover is currently collecting samples on the martian surface for potential return to Earth and planning is underway to develop facilities to study these samples. Perseverance will collect up to 38 samples that will be sealed in TiN tubes. As long as the tubes remain sealed the samples will be metastable. However, as soon as a tube is opened, or headspace gas is extracted these samples will begin to re-equilibrate with their new surroundings. The MSPG2 time-sensitive science sub-group attempted to quantify the rates at which alteration is likely to occur assuming the samples are opened and stored in a nitrogen atmosphere at room temperature. The group also recommended ~20 instruments for inclusion in a sample receiving facility to allow the time sensitive properties of these samples to be measured before they are irreversibly altered.

Aaron B Regberg↗

Limits on Runoff Episode Duration for Early Mars: Integrating Lake Hydrology and Climate Models

Fluvio-lacustrine features on the martian surface attest to a climate that was radically different in the past. Since climate models have difficulty sustaining a liquid hydrosphere at the surface, multiple cycles of runoff episodes may have characterized the ancient Mars climate. A fundamental question thus remains: what was the duration of these runoff-producing episodes? Here we use morphometric measurements from newly identified coupled lake systems, containing both an open- and a closed-basin lake (n=7). We combined hydrological balances with precipitation outputs from climate models, and found that breaching runoff episodes likely lasted 102−105yr; other episodes may have been shorter but could not be longer. Runoff episode durations are model-dependent and spatiallyvariable, and no27climate model scenario can satisfy a unique duration for all coupled systems. In the near future, these quantitative constraints on early Mars lake persistence may be tested through in situ observations from Perseverance rover. Plain Language Summary Ancient river and lake beds on the martian surface point to a climate that was radically different in the past, unlike the dry, cold desert that Mars is today. It experienced significant liquid water flowing across the surface (i.e., ‘runoff’) and hosted long-lived bodies of water (lakes and seas). However, scientists that generate models to simulate the ancient Mars climate have difficulty sustaining this proposed liquid water cycle at the surface. One possible hypothesis is that multiple cycles of individual liquid water episodes may have characterized the ancient martian climate (i.e. runoff episodes). A fundamental question thus remains: what was the duration of these individual runoff-producing episodes? Here we use an approach that takes advantage of unique martian lake system, ‘coupled’ lake systems, and their shapes. We combined these measurements with precipitation results from previous climate models, and found that runoff episodes likely lasted 100-10,000 years, requiring a global climate mechanism that generated repeated cycles of this duration. Ultimately, our results can be tested through observations made by NASA’s Perseverance rover, shedding light on the uninterrupted duration of surface water on Mars and its potential to host life in the past.

Gaia Stucky de Quay↗

Assessment of the Mars 2020 Entry, Descent, and Landing Simulation

On February 18, 2021, the Mars 2020 Perseverance rover successfully landed inside Jezero Crater at 18.44463 deg North latitude and 77.45088 deg East longitude. At 1026 kg, Perseverance is the largest, most sophisticated rover ever delivered to another planet. This event marked the ninth successful landing and fifth rover to be delivered at Mars. The Program to Optimize Simulated Trajectories II (POST2) is a trajectory simulation tool maintained by the NASA Langley Research Center. POST2 was the prime EDL performance simulation for Mars 2020. This tool has significant heritage on the previous Pathfinder, MER, Phoenix, InSight, and MSL landings. This paper presents a few initial comparisons between EDL flight telemetry and POST2 simulation predictions. These comparisons are important in order to understand how each of the individual models performed, as well as the integrated simulation as a whole. This information is fed forward to future missions, which benefit from the knowing where additional resources or study are needed and where uncertainties may be reduced to enable improved performance.

David W Way↗

Assessment of the Mars 2020 Entry, Descent, and Landing Simulation

On February 18, 2021, the Mars 2020 Perseverance rover successfully landed inside Jezero Crater at 18.44463 deg North latitude and 77.45088 deg East longitude. At 1026 kg, Perseverance is the largest, most sophisticated rover ever delivered to another planet. This event marked the ninth successful landing and fifth rover to be delivered at Mars. The Program to Optimize Simulated Trajectories II (POST2) is a trajectory simulation tool maintained by the NASA Langley Research Center. POST2 was the prime EDL performance simulation for Mars 2020. This tool has significant heritage on the previous Pathfinder, MER, Phoenix, InSight, and MSL landings. This paper presents a few initial comparisons between EDL flight telemetry and POST2 simulation predictions. These comparisons are important in order to understand how each of the individual models performed, as well as the integrated simulation as a whole. This information is fed forward to future missions, which benefit from the knowing where additional resources or study are needed and where uncertainties may be reduced to enable improved performance.

David Way↗