Engineering topics

Brandi Carrier

Publications and source records attributed to Brandi Carrier.

4 records

NASA NTRS2022

Thresholds of Temperature and Time for Mars Sample Return: Final Report of The Mars Sample Return Temperature-Time Tiger Team

The time-temperature tiger team (T4) was chartered by NASA and ESA to evaluate the risks to the scientific return of the MSR samples if they are exposed to temperatures between +30 and +60 ⁰C for different amounts of time. This team consists of 13 scientists, who were selected based on their scientific background to represent the scientific disciplines that are expected to be the ones that will be the most affected if such heating were to happen. The expertise of the team will help to understand whether exposing the MSR samples to temperatures between +30 and +60 ⁰C will pose any risk to the sample integrity and therefore, to future scientific investigations. Key processes identified by the T4 were: the release of volatiles by desorption and sublimation and release from condensed phases (interiors, decomposition, dehydration); chemical reactions including gas-gas and gas-solid; deliquescence of hygroscopic salts; acid/base interactions (potential for extreme pH conditions); aqueous redox reactions, isotopic exchange (aqueous phases, minerals, gasses, organic phases); condensation and freezing (in the after-heating cooling phase) and interactions with the sample tube materials. There is potential for multiple interactions and overlapping effects. For inorganic materials and the records they represent, over both long time scales (hours to days) and short time scales (minutes to hours) no temperature excursion above +30 °C could be accommodated without loss of science (Figure 1.1). While there will be some robust constituents (feldspars, quartz, pyroxenes, etc.) that are unaffected, there will also be some less robust constituents (salts, phyllosilicates, radicals, etc.) that are affected across all temperature ranges ≤60 °C. For organic materials, in particular organic biosignatures, the risks reflect that preservation is reliant on a number of processes, and a change in one component within a sample tube can affect another. For organic materials, over long timescales of hours to days no temperature excursion above +30 °C could be accommodated without loss of science, but over shorter time scales (minutes to hours), raising the temperature to 40 °C could be manageable without major disruption to science, whereas temperatures above 40 °C would lead to significant losses. The consideration of these findings by the MSR team will help to maintain the fidelity of samples returned from Mars in the future and maximize scientific return when analyzed in Earth laboratories.

Mark A Sephton↗

NASA NTRS2021

Perseverance’s Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) Investigation

The Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) is a robotic arm-mounted instrument on NASA’s Perseverance rover. SHERLOC has two primary boresights. The Spectroscopy boresight generates spatially resolved chemical maps using fluorescence and Raman spectroscopy coupled to microscopic images (10.1 μm/pixel). The second boresight is a Wide Angle Topographic Sensor for Operations and eNgineering (WATSON); a copy of the Mars Science Laboratory (MSL) Mars Hand Lens Imager (MAHLI) that obtains color images from microscopic scales (∼13 μm/pixel) to infinity. SHERLOC Spectroscopy focuses a 40 μs pulsed deep UV neon-copper laser (248.6 nm), to a ∼100 μm spot on a target at a working distance of ∼48 mm. Fluorescence emissions from organics, and Raman scattered photons from organics and minerals, are spectrally resolved with a single diffractive grating spectrograph with a spectral range of 250 to ∼370 nm. Because the fluorescence and Raman regions are naturally separated with deep UV excitation (<250 nm), the Raman region ∼ 800 – 4000 cm−1 (250 to 273 nm) and the fluorescence region (274 to ∼370 nm) are acquired simultaneously without time gating or additional mechanisms. SHERLOC science begins by using an Autofocus Context Imager (ACI) to obtain target focus and acquire 10.1 μm/pixel greyscale images. Chemical maps of organic and mineral signatures are acquired by the orchestration of an internal scanning mirror that moves the focused laser spot across discrete points on the target surface where spectra are captured on the spectrometer detector. ACI images and chemical maps (< 100 μm/mapping pixel) will enable the first Mars in situ view of the spatial distribution and interaction between organics, minerals, and chemicals important to the assessment of potential biogenicity (containing CHNOPS). Single robotic arm placement chemical maps can cover areas up to 7x7 mm in area and, with the < 10 min acquisition time per map, larger mosaics are possible with arm movements. This microscopic view of the organic geochemistry of a target at the Perseverance field site, when combined with the other instruments, such as Mastcam-Z, PIXL, and SuperCam, will enable unprecedented analysis of geological materials for both scientific research and determination of which samples to collect and cache for Mars sample return.

Rohit Bhartia↗

NASA NTRSDate not supplied

An Overview of SHERLOC Raman and Fluorescence Spectroscopy Results Obtained During Perseverance’s Green Zone Campaign at Jezero Crater, Mars

The Perseverance rover landed in Jezero crater, Mars, in February 2021. The field site was chosen because orbiter data provided evidence that the crater hosted an ancient (>2.7 Ga) fluvio-lacustrine environment. The Octavia E. Butler landing site is located ~1.9 km east of the erosional remnant of the Jezero river delta. Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) is an arm-mounted instrument that combines fluorescence and Raman spectroscopy with microscopic imaging to analyze geological materials in order to better understand the history of the environments recorded in the rocks within Jezero crater and to search for potential biosignatures. SHERLOC has two microscopic cameras, the Autofocus and Context Imager (ACI) and the Wide-Angle Topographic Sensor for Operations and eNgineering, (WATSON). These subsystems obtain high spatial resolution (10.1–100 µm/pixel) images to identify grain-scale structure and texture. SHERLOC spectroscopy enables high-sensitivity detection, characterization, and spatially-resolved correlation of trace organic materials. SHERLOC’s 248.6 nm deep UV laser generates a 100 µm-diameter spot. Photons generated by Raman scattering and fluorescence emission are collected and the spectra are downlinked to Earth for analysis. Knowledge of where the laser is pointed allows for mineral and compositional maps to be generated and overlain in ACI and WATSON images. Early spectroscopy observations focused on natural rock surfaces at targets named Nataani (sol 83), Bi_la_sana (sol 98) and Foux (sol 141). These surfaces included patches of aeolian dust that had settled upon the rocks. Perseverance’s abrasion tool is expected to become available in August 2021; it will grind to depths of 14 mm to remove dust and penetrate coatings and weathering rinds. This presentation will summarize major results from analysis of the rocks examined by SHERLOC during Perseverance’s first science and sample coring campaign (Green Zone Campaign).

Luther W Beegle↗

NASA NTRSDate not supplied

Connecting Community Scientific Hypotheses to Mars Sample Science

The proposed Mars Sample Return (MSR) program seeks to bring back to Earth a set of specially curated samples from the surface of Mars. The first segment of the MSR program is presently under-way; the Mars 2020 rover Perseverance has, to date, collected 24 samples of martian rock, regolith, and at-mosphere within Jezero crater. Its geologically diverse rock sample set can provide insight into the time evolu-tion of the Jezero environment, including the possible preservation of ancient biosignatures. Presently, a cache of 10 samples has been deposited in the Three Forks region on the floor of Jezero crater. These sam-ples, deemed scientifically return worthy by the Mars science community [1], are intended as a contingency sample set, as Perseverance has subsequently obtained more samples, and is therefore storing a more compre-hensive and scientifically valuable set of samples that will grow as the rover ascends to the rim of Jezero crater. The return of samples from Mars has been identi-fied as the highest priority planetary mission in the past three National Academies Decadal Surveys [2-4]. Sub-stantial work has gone into establishing science objec-tives for an MSR program, an overall framework for sample retrieval and analysis, and the expected impact on future Mars science and exploration (e.g., [5]). These objectives have been established at a relatively high level, e.g., “Interpret the primary geologic pro-cesses and history that formed the martian geologic rec-ord, with an emphasis on the role of water.” (Objective 1 in [5]) and are designed to encapsulate the broad sci-entific priorities of, and lay the groundwork for, inves-tigation strategies and measurements to be conducted by a future MSR program. It is from this overarching framework that the Connecting Community Scientific Hypotheses to Mars Sample Science workshop (‘The Workshop’) was conceived, with the purpose of distil-ling these high-level scientific objectives into discrete, testable hypotheses across a range of scientific disci-plines. The output of the workshop is meant to be a ‘hy-pothesis document’ serving as a starting point for cata-loging and condensing specific hypotheses for consid-eration by the scientific community. The template for this approach is based on the “driving hypotheses” de-veloped by the OSIRIS-REx team as part of their Sam-ple Analysis Plan [6].

Michael A Mischna↗