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Choukroun, Mathieu

Publications and source records attributed to Choukroun, Mathieu.

At least 19 records

Thermal Analysis of Landers using Radioisotope Power Systems on Ice Worlds

The surfaces of Ice Worlds record evidence of interior processes, chemical potential, habitability, and potentially life within the interior. Volatile and organic chemistry at the surface is critical in determining habitability and detecting the presence of past or extant life. Radioisotope Power Systems (RPS) could be an enabling technology for in situ missions to ice worlds, providing both power and heat for long durations where solar power would not be feasible. However, it is necessary to understand the potential impact of RPS upon the local environment, to ensure that the rejected heat from RPS does not compromise science measurements or planetary protection requirements. To address these concerns, an RPS Ice World Lander Study was carried out in 2019 to investigate possible requirements on RPS surface mission concepts and approaches to excess heat management. The study focused on two destinations that are representative of the range of potential environments: Europa and Enceladus.Initial analysis showed that, due to the very low pressures on the surfaces of most ice world targets, surface melting does not occur because the water ice does not meet the triple-point. A 4 kW heat source suspended above the surface of Europa or Enceladus would not cause any melting, only sublimation.The study used a surface sublimation limit of 10 cm over a two-year period (the baseline for the recent Europa Lander study). To stay within this limit, Europa, with its relatively warm surface, could tolerate only 10 W/m2 of surface heat flux. Enceladus, with its relatively cold pure ice composition, could tolerate up to 100 W/m2.Various lander and heat shield configurations were analyzed for their heat flux radiated from the RPS to the surface. For a given heat shield configuration, the study team determined the minimum height of the RPS above the surface for which the heat flux would be within the accepted parameters for Europa and for Enceladus. Based on these thermal analyses, such RPS-powered landers could remain compliant with science investigation and planetary protection requirements with only modest mass allocated to spacecraft thermal accommodations.

Perl, Scott

The Dual-Rasp Sampling System Design with Closed Pneumatic Sample Transfer

The novel Dual-Rasp sampling system has been developed for landed missions to low gravity planetary bodies and is particularly well suited for the unique environment of Saturn’s moon Enceladus. The Dual-Rasp sampling system has two counter-rotating rasp cutters that remove material from the surface and direct it into a guide. The cuttings follow the guide into a sample collection cup. When the sampling collection completes, the tool reconfigures by rotating the guide to create a closed circuit for pneumatic sample transfer from the collection cup to science instruments on the lander. A valve opens a gas tank and the gas flows from that tank into the sample collection cup and down rigid tubing to the science instruments chamber on the lander. A two degree of freedom arm with base actuators is used to deploy the sampler and control its sampling location.

Heness, Andrew B.

Icy and Ocean World Exploration Enabled by Radioisotope Power Systems

As the interest in exploring icy and ocean worlds gains increasing traction among scientists and mission communities, there are many potential icy and ocean world targets for in-situ lander missions. Potential targets include Europa, Enceladus, Titan, Triton, Ceres, Pluto, and more, which will allow the scientific community to address icy and ocean world related questions for understanding the distribution of life in the Solar System. Beyond Jupiter, solar power is infeasible for any landed missions and primary batteries are infeasible for long-duration missions. Radioisotope Power Systems (RPS) can be enabling for these long-duration in-situ missions. However, the interaction of RPS waste heat with icy world surfaces must be understood to assure the science and mission communities that RPS are a safe, enabling option to explore the surface of icy bodies. This paper describes a study for the RPS Program that was conducted by the RPS Mission Analysis Team and JPL’s Team X to investigate the system-level impact of a heat rejection system that would be required for RPS-enabled exploration of icy and ocean worlds.

Lee, Young H

The Dual-Rasp Sampling System for an Enceladus Lander

The Dual-Rasp sampling system has been developed for the unique sampling environment of a lander mission to the surface of Saturn’s moon Enceladus. Plume material from the subsurface ocean that has fallen to the surface is desired resulting in an objective to sample the topmost layer of icy material. The low gravity and potential large range of surface properties are challenges for the sampling system. The Dual-Rasp sampling system has two counter-rotating rasp cutters with teeth that remove material that is thrown up between the cutters. Two prototypes of the Dual-Rasp sampling system were built and tested, one with a carousel and one that uses pneumatics for sample transfer.

Ubellacker, Samuel

The Dual-Rasp Sampling System for an Enceladus Lander

The Dual-Rasp sampling system has been developed for the unique sampling environment of a lander mission to the surface of Saturn’s moon Enceladus. Plume material from the subsurface ocean that has fallen to the surface is desired resulting in an objective to sample the topmost layer of icy material. The low gravity and potential large range of surface properties are challenges for the sampling system. The Dual-Rasp sampling system has two counter-rotating rasp cutters with teeth that remove material that is thrown up between the cutters. Two prototypes of the Dual-Rasp sampling system were built and tested, one with a carousel and one that uses pneumatics for sample transfer.

Backes, Paul

Sampling tool concepts for Enceladus Lander in-situ analysis

A potential future in-situ lander mission to the surface of Enceladus could be the lowest cost mission to determine if life exists beyond Earth since material from the subsurface ocean, where the presence of hydrothermal activity has been strongly suggested by the Cassini mission, is available on its surface after being ejected by plumes and then settling on the surface. In addition, the low radiation environment of Enceladus would not significantly alter the chemical makeup of samples recently deposited on the surface. A study was conducted to explore various sampling devices that could be used by an in-situ lander mission to provide 1cc to 5cc volume samples to instruments. In addition to temperature and vacuum environmental conditions, the low surface gravity of Enceladus (1% of Earth gravity) represents a new challenge for surface sampling that is not met by sampling systems developed for microgravity (e.g., comets and asteroids) or higher gravity (e.g., Europa 13%g, Moon 16%g, or Mars 38%g) environments. It is desired to acquire surface plume material that has accumulated in the top 1cm to ensure acquisition of the least processed material. Several sampling devices were developed or adapted and then tested in simulated conditions that resemble the Enceladus surface properties. These devices and test results are presented in this paper.

Genta, Giancarlo

A Submm-Wave Comet Explorer for Water Isotopic Composition Measurements

Remote submm-wave spectrometers have the capability of providing statistically significant numbers of isotopic composition measurements within the budget constraints of available planetary missions. This talk will present a mission and instrument concept that would enable an accurate measurement of the D/H ratio on not one but several dozens of comets in a four-year mission lifetime. The instrument would utilize advanced cryogenic detectors that would allow us to measure the abundance of the para and ortho spin states of water and its isotopologues. State of the art superconducting heterodyne receivers have been developed that provide detection sensitivities approaching the quantum limit in the 500 GHz frequency range enabling the measurement of D/H ratio on around 50 comets from an observatory stationed for example at the thermally benign Lagrange point L2.

Feldman, Sabrina