Initial Reports introduction

mission specific

M20

Initial reports are created by the Mars 2020 science team for each sample collection. The material below is taken from the initial reports and is common to all samples.

Preface

A central goal of the Mars 2020 mission is collection of scientifically-selected martian rock, regolith, and atmosphere samples for possible return to Earth by future missions. This is an ambitious undertaking: Perseverance carries 38 sample tubes and 5 contamination-knowledge “witness tubes” to be filled over the course of the mission. Using the rover’s instruments, high priority outcrops must be identified, and the characteristics of each acquired sample and its surroundings investigated. With such a large number of samples to acquire and with an anticipated short interval between their acquisition, it is important to record in near real-time what the Mars 2020 Science Team has learned about each sample. The Mars 2020 Initial Reports series fills this need. A sample’s Initial Report is a set of field notes recording what is known about the sample and how it fits into its surroundings. The goal is to have each report completed within three weeks of sample acquisition, long enough to have downlinked, processed, and completed an initial high-level interpretation of the data, but short enough that the sample is still fresh in the team’s memory. Just like conventional field notes, the Initial Report is not updated after completion. The Initial Report is therefore preliminary, and the interpretations and even some of the underlying measurements will be revised and described more fully in detailed follow-on publications. The goal of the Initial Reports collection is to provide a timely, routine, systematic and preliminary narrative description of all the acquired samples in a single compendium. The Initial Reports complement the Sample Dossiers - a compilation of the digital records related to each sample. The Initial Reports series facilitates intercomparison among samples already collected as well as rocks under consideration for sampling over the course of the mission. It may also prove useful for prioritization of samples for Earth return and as a quick reference guide after samples arrive on Earth.

K.A. Farley, Project Scientist

K.M. Stack, Deputy Project Scientist

Participating Scientists

The Mars 2020 Science Team includes individuals selected by NASA to guide sample selection, interpretation, and documentation, including preparation of these Initial Reports. For the Prime Mission these individuals are:

  • Kathleen Benison, West Virginia University
  • Tanja Bosak, Massachusetts Institute of Technology
  • Barbara Cohen, NASA Goddard Space Flight Center
  • Andy Czaja, University of Cincinnati
  • Vinciane Debaille, FNRS-Université Libre de Bruxelles
  • Libby Hausrath, University of Nevada Las Vegas
  • Chris Herd, University of Alberta
  • Keyron Hickman-Lewis, Natural History Museum London
  • Lisa Mayhew, University of Colorado Boulder
  • Mark Sephton, Imperial College London
  • Davis Shuster, University of California Berkeley
  • Sandra Siljeström, RISE Research Institutes of Sweden
  • Justin Simon, NASA Johnson Space Center
  • Ben Weiss, Massachusetts Institute of Technology
  • Maria-Paz Zorzano, Centro de Astrobiología, Spain

Explanatory notes for Mars 2020 initial reports

Sample Designation

The standardized format for sample designations is M2020-sol-N name. M2020 refers to the mission that collected the sample, sol indicates the mission sol of sample tube sealing, N refers to the sequential number of the sample (or witness blank) acquisition, and name is the informal name applied to that sample and derived from the quadrangle in which the core was acquired. In the case of a witness blank acquisition, name is simply “WB” followed by the sequential number of the witness blank, starting with 1 and incrementing (e.g. WB1).

The same naming scheme is used for paired samples (i.e., two cores acquired with one associated STOP list execution; see below for definition of STOP list), except sol, N, and name all refer to the second member of the pair.

In typical usage the sample name alone is sufficient to uniquely identify a specific core. Because paired samples share a STOP list data set, when describing characteristics that refer to both members of paired samples, hyphenation of sample names will provide clarity: e.g., name1-name2.

Date of Coring (or Exposure-Activation-Sealing)

This is the calendar date on which the corer was placed on the rock surface to begin acquisition. Ordinarily, coring is completed in one sol. In the case of a witness blank, the dates of initial exposure, activation (inner seal puncture), and sealing are indicated.

Estimated Volume Recovered

The rock volume (Vrock) estimate is derived from the penetration depth of the volume probe, a rod inserted into the tube after sample acquisition (in practice the tube is manipulated while the rod is fixed in place). Volume is computed from the implied length of sample multiplied by an assumed cylindrical cross section corresponding to the coring bit inner diameter d=13.4 mm. The core itself has d=13 mm; the 0.4 mm difference in diameter between the bit and the core is assumed to be filled by cuttings and so contributes to acquired rock volume. A full length core is typically 6 cm long, though shorter lengths can be commanded and will sometimes be all that is acquired. Note that void spaces between core fragments may exist, such that the true sample volume may be less than this estimate.

Coring Bit Number

Perseverance carries 6 rock coring bits and 2 regolith bits. The bit number used here provides insight to usage history that may be relevant for contamination and cross-contamination assessment.

Core Orientation

Three pieces of information are needed to orient the core in the Martian geographic frame (also known as the SITE frame) (Fig. 1). First, two angles orient the core’s pointing vector. Second, the core’s roll is noted by marking the pre-drilling WATSON image of the core face. The core orientation pointing vector is estimated as equal to the orientation of the coring drill after pre-loading on the core target.

The core pointing vector is quantified by the azimuth and hade. The azimuth is defined as the clockwise angle of the horizontal projection of the core y-axis, cy, from geographic north, sx, where the cy-axis lies in the martian geographic vertical plane. The hade is defined as the angle of the core face from martian geographic horizontal (sx-sy plane). These angles are obtained from coring drill and rover body ancillary orientation data at the time of pre-loading of the coring drill.

The core roll is quantified by an angle α, defined as the clockwise angle from the WATSON y-axis (wy) to cy as viewed in the pre-coring WATSON images. WATSON 6-7-cm standoff images are typically used for this purpose.

Fig. 1. Orientation system for cores collected by the Perseverance rover. Shaded cylinder is core with cutaway view in lower right quadrant. Martian geographic east, north, and down are the SITE axes, sx, sy and sz, respectively. The pointing vector, cx, points into outcrop and is normal to the core face and the cy axis lies in the vertical plane. The azimuth is the clockwise angle from geographic north of the projection of the cy-axis onto the Martian horizontal (sx-sy) plane. The hade is the angle of cx from vertical. The core roll, α, is defined as the clockwise angle from the WATSON pre-coring image y-axis, wy, to cy; this direction is marked with an arrow on the WATSON image. Adapted from Butler (1992) Paleomagnetism: Magnetic Domains to Geologic Terranes, Blackwell Scientific, 319 pp.

Sample Tube, Seal, and Ferrule Serial Numbers

Every sealed tube carries a unique set of serial numbers that will allow downstream identification. SN’s are stamped into each tube, seal, and ferrule (the ferrule SN is commonly visible in Cachecam images).

ACA Temperature at Time of Sealing

Sample tubes are sealed in the Adaptive Caching Assembly (ACA). Mechanisms in this subsystem are actively heated, so sealing occurs at temperatures higher than ambient conditions around the rover. The temperature recorded here is the average of the temperatures recorded on the Sealing Station and the Sample Handling Arm end effector. These temperatures are likely warmer than the sample and the associated head space gas.

Estimated Rover-Ambient Pressure and Temperature at Time of Sealing

Atmospheric temperature and pressure are obtained from MEDA. When MEDA data was not acquired on the same sol as sample sealing (often the case given energy limitations), the average values of pressure and temperature are estimated from the closest sol or sols. The reported temperature is the minimum of MEDA ATS 4 and 5, the sensors located 0.84 m above the surface.

Estimated Amount of Martian Atmosphere Headspace Gas

The estimated amount of headspace gas in moles (nh) is computed from the ideal gas law and assuming the rover ambient temperature (T) and pressure (P) described above.

nh= P (Vtube - Vrock)/ RT

where R is the gas constant. VT is assumed to be 12 cm3. The actual temperature of the gas upon sealing is difficult to estimate because the Adaptive Caching Assembly (ACA) is substantially warmer than rover surroundings, typically by almost 100 K. For consistency we assume rover ambient temperature in this calculation, recognizing that it is an upper limit. A lower limit would be obtained by using the reported ACA temperature in the above equation.

Abrasion Patch Name and Depth

To minimize possible degradation of the sample, much of the data associated with a given sample is acquired on a 5 cm diameter abrasion patch acquired within a few tens of cm of the coring site, and in the same lithology. This IR entry gives the name of that patch and its depth relative to the highest topographic feature in the 5 cm diameter circle that was abraded.

Anomalous Behavior

This entry highlights noteworthy deviations from the standard sampling activities or their expected results.

STOP List

To expedite the sample collection and acquisition process, the Mars 2020 Team developed a minimum set of observations to be performed in association with each sample. This Standardized Observation Protocol, or STOP list, was encoded into an optimized sample sol path for efficient and repeatable execution. STOP list observations form the main data set for each sample’s Initial Report. A standardized set of observations on each sample permits a templatized Initial Report format. Although the STOP list is likely to evolve as the team learns what observations provide highest science value, it is the intention that the overall format be retained.

Instrument and Mission References

Allwood, Abigail C., Lawrence A. Wade, Marc C. Foote, William Timothy Elam, Joel A. Hurowitz, Steven Battel, Douglas E. Dawson, et al. "PIXL: Planetary Instrument for X-Ray Lithochemistry." Space Science Reviews 216, 134. https://doi.org/10.1007/s11214-020-00767-7.

Balaram, J., MiMi Aung, and Matthew P. Golombek. "The Ingenuity Helicopter on the Perseverance Rover." Space Science Reviews 217, 56. https://doi.org/10.1007/s11214-021-00815-w.

Bell, J. F., J. N. Maki, G. L. Mehall, M. A. Ravine, M. A. Caplinger, Z. J. Bailey, S. Brylow, et al. "The Mars 2020 Perseverance Rover Mast Camera Zoom (Mastcam-Z) Multispectral, Stereoscopic Imaging Investigation." Space Science Reviews 217, 24. https://doi.org/10.1007/s11214-020-00755-x.

Bhartia, Rohit, Luther W. Beegle, Lauren DeFlores, William Abbey, Joseph Razzell Hollis, Kyle Uckert, Brian Monacelli, et al. "Perseverance’s Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) Investigation." Space Science Reviews 217, 58. https://doi.org/10.1007/s11214-021-00812-z.

Farley, Kenneth A., Kenneth H. Williford, Kathryn M. Stack, Rohit Bhartia, Al Chen, Manuel de la Torre, Kevin Hand, et al. "Mars 2020 Mission Overview." Space Science Reviews 216, 142. https://doi.org/10.1007/s11214-020-00762-y.

Hamran, Svein-Erik, David A. Paige, Hans E. F. Amundsen, Tor Berger, Sverre Brovoll, Lynn Carter, Leif Damsgård, et al. "Radar Imager for Mars’ Subsurface Experiment—RIMFAX." Space Science Reviews 216, 128. https://doi.org/10.1007/s11214-020-00740-4.

Hayes, Alexander G., P. Corlies, C. Tate, M. Barrington, J. F. Bell, J. N. Maki, M. Caplinger, et al. "Pre-Flight Calibration of the Mars 2020 Rover Mastcam Zoom (Mastcam-Z) Multispectral, Stereoscopic Imager." Space Science Reviews 217, 29. https://doi.org/10.1007/s11214-021-00795-x.

Hecht, M., J. Hoffman, D. Rapp, J. McClean, J. SooHoo, R. Schaefer, A. Aboobaker, et al. "Mars Oxygen ISRU Experiment (MOXIE)." Space Science Reviews 217, 9. https://doi.org/10.1007/s11214-020-00782-8.

Kinch, K. M., M. B. Madsen, J. F. Bell, J. N. Maki, Z. J. Bailey, A. G. Hayes, O. B. Jensen, et al. "Radiometric Calibration Targets for the Mastcam-Z Camera on the Mars 2020 Rover Mission." Space Science Reviews 216, 141. https://doi.org/10.1007/s11214-020-00774-8.

Maki, J. N., D. Gruel, C. McKinney, M. A. Ravine, M. Morales, D. Lee, R. Willson, et al. "The Mars 2020 Engineering Cameras and Microphone on the Perseverance Rover: A Next-Generation Imaging System for Mars Exploration." Space Science Reviews 216, 137. https://doi.org/10.1007/s11214-020-00765-9.

Manrique, J. A., G. Lopez-Reyes, A. Cousin, F. Rull, S. Maurice, R. C. Wiens, M. B. Madsen, et al. "SuperCam Calibration Targets: Design and Development." Space Science Reviews 216, 138. https://doi.org/10.1007/s11214-020-00764-w.

Maurice, S., R. C. Wiens, P. Bernardi, P. Caïs, S. Robinson, T. Nelson, O. Gasnault, et al. "The SuperCam Instrument Suite on the Mars 2020 Rover: Science Objectives and Mast-Unit Description." Space Science Reviews 217, 47. https://doi.org/10.1007/s11214-021-00807-w.

Moeller, Robert C., Louise Jandura, Keith Rosette, Matt Robinson, Jessica Samuels, Milo Silverman, Kyle Brown, et al. "The Sampling and Caching Subsystem (SCS) for the Scientific Exploration of Jezero Crater by the Mars 2020 Perseverance Rover." Space Science Reviews 217, 5. https://doi.org/10.1007/s11214-020-00783-7.

Newman, C. E., M. de la Torre Juárez, J. Pla-García, R. J. Wilson, S. R. Lewis, L. Neary, M. A. Kahre, et al. "Multi- Model Meteorological and Aeolian Predictions for Mars 2020 and the Jezero Crater Region." Space Science Reviews 217, 20. https://doi.org/10.1007/s11214-020-00788-2.

Pla-García, Jorge, S. C. R. Rafkin, G. M. Martinez, Á. Vicente-Retortillo, C. E. Newman, H. Savijärvi, M. de la Torre, et al. "Meteorological Predictions for Mars 2020 Perseverance Rover Landing Site at Jezero Crater." Space Science Reviews 216, 148. https://doi.org/10.1007/s11214-020-00763-x.

Rodriguez-Manfredi, J. A., M. de la Torre Juárez, A. Alonso, V. Apéstigue, I. Arruego, T. Atienza, D. Banfield, et al. "The Mars Environmental Dynamics Analyzer, MEDA. A Suite of Environmental Sensors for the Mars 2020 Mission." Space Science Reviews 217, 48. https://doi.org/10.1007/s11214-021-00816-9.

Stack, Kathryn M., Nathan R. Williams, Fred Calef, Vivian Z. Sun, Kenneth H. Williford, Kenneth A. Farley, Sigurd Eide, et al. "Photogeologic Map of the Perseverance Rover Field Site in Jezero Crater Constructed by the Mars 2020 Science Team." Space Science Reviews 216, 127. https://doi.org/10.1007/s11214-020-00739-x.

Wiens, Roger C., Sylvestre Maurice, Scott H. Robinson, Anthony E. Nelson, Philippe Cais, Pernelle Bernardi, Raymond T. Newell, et al. "The SuperCam Instrument Suite on the NASA Mars 2020 Rover: Body Unit and Combined System Tests." Space Science Reviews 217, 4. https://doi.org/10.1007/s11214-020-00777-5.

see also