Solar system

Abstract:

Astrobotic's Peregrine Mission-1 spacecraft experienced a propulsion system anomaly that prevented the lander from reaching the Moon. During the mission, several instruments operated successfully in cis-lunar space. Among them, the Peregrine Ion Trap Mass Spectrometer (PITMS) measured both the presence of outgassing water and nitrogen oxides traceable to the MON-25 oxidizer. We performed Direct Simulation Monte Carlo (DSMC) studies of the oxidizer leak on Peregrine to characterize the gas diffusion from the leak to the instrument, mediated by inter-species collisions and gas–surface interaction. We conclude that the latter process was prevalent and that diffusion paths through Peregrine are necessary to explain the PITMS detections. Our DSMC study and estimation of Peregrine's outgassing rate suggest that, at the early stage of the mission, the spacecraft released water at a rate comparable to the Space Shuttle and at a much larger rate than typical spacecraft during science operations. This provides useful information for planning future operations of science instruments on commercial missions.

Abstract:

We needed to evaluate available orbital data of NASA’s Volatiles Investigating Polar Exploration Rover (VIPER) mission area in order to derive a variety of maps to help the science team identify scientifically interesting places for the rover to visit and to provide scientific context for our mission. Some of these maps also fulfilled engineering and mission design needs to enable safe and efficient landing and roving. We incorporated data from the Lunar Reconnaissance Orbiter Camera, the Lunar Orbital Laser Altimeter, the Mini-RF instrument, the Chandrayaan-2 Orbital High Resolution Camera, the Korean Pathfinder Lunar Orbiter’s Shadowcam, the Kaguya Spectral Profiler and Multiband Imager, and the Chandrayaan-1 Moon Mineralogy Mapper. We used a variety of techniques to build these maps, including stereogrammetry, shape-from-shading, ice stability depth and surface temperature calculations, and the horizon method for solar illumination and direct-to-Earth communications maps. Altogether, these maps allowed us to survey for boulders, evaluate features in permanently shadowed regions that VIPER might explore, provide mineralogic context for what VIPER’s instruments may learn, estimate the ages and radar properties of craters in the VIPER mission area, and evaluate the potential for gravity traverses with the rover. These data and techniques provided a rich set of information from which both the VIPER science team and engineering teams were able to draw in order to plan a safe landing and to plan a VIPER surface mission that will be both scientifically valuable and robust from an operational perspective.

Abstract:

Venus is home to thousands of volcanoes, with a wide range of volumes and sizes. Its surface is relatively young, with a temperature of approximately 735 K and an atmosphere of 92 bar. Past and possible ongoing volcanic outgassing is expected to provide a source to the sustenance of this massive atmosphere, dominated by CO2 and SO2. The lower atmosphere can be investigated in the near-infrared transparency windows on the nightside, such as the 2.3μm thermal emission window, which provides a chance of detection of species with volcanic origin, such as water vapor. The Planetary Spectrum Generator was used to simulate the nightside 2.3μm thermal emission window of Venus. We simulated the effect of a volcanic gas plume rising to a ceiling altitude, for species such as H2O, CO, OCS, HF and SO2. The sensitivity of the radiance spectrum at different wavelengths was explored as an attempt to qualitatively access detection for future measurements of both ground-based and space-instrumentation. We conclude from our qualitative analysis that for the H2O, CO and OCS plumes simulated there is potential to achieve a detection in the future, given a minimum required signal-to-noise ratio of 50. For SO2 and HF plumes, a higher signal-to-noise ratio would be needed.

Abstract:

The return home of the OSIRIS-REx spacecraft in September 2023 marked only the fifth time that anartificial object entered the Earth’s atmosphere at interplanetary velocities. Although rare, such events serve as valuable analogs for natural meteoroid re-entries; enabling study of hypersonic dynamics, shock wavegeneration, andacoustic-to-seismic coupling. Here, wereportonthesignaturesrecordedbyadense(100mscale)11-station array located almost directly underneath the capsule’s point of peak atmospheric heat ing in northern Nevada. Seismic data are presented, which allow inferences to be made about the shape of the shock wave’s footprint on the surface, the capsule’s trajectory, and its flight parameters.