Dr Tristram Warren

Abstract:

The Lunar Trailblazer mission aimed to assess the presence of water on the lunar surface using imaging spectroscopy in visible shortwave infrared (VSWIR) coupled with high‐resolution multispectral imaging in thermal midwave‐infrared (MWIR), captured simultaneously over the same target from orbit around the Moon with two different instruments. Uncertainties in clock timing, instrument models, and instrument pointing knowledge manifest as geospatial offsets between the two data sets that must be corrected in post‐processing to enable co‐registration, tying the acquired images to their precise latitudes and longitudes on the Moon. This work describes an algorithmic approach to co‐registering and geolocalizing images after acquisition without high precision instrument and spacecraft pointing models, the Iterative Matching Pipeline for Post‐Acquisition Image Localization (IMPPAIL), utilizing previously acquired data for development. We use Lunar Orbiter Laser Altimetry (LOLA) and Kaguya data to make shaded relief maps as the basemap on which to project data. To test our processing pipeline prior to Lunar Trailblazer data collection, we use Moon Mineralogy Mapper (M3) data for VSWIR images and simulated MWIR images. When demonstrated on these data sets, IMPPAIL produces a 98% success rate registering VSWIR data to LOLA/Kaguya shaded relief maps and successfully co‐registered MWIR and VSWIR in all four simulation cases. We include a code package with software tools allowing this algorithm to be used for a variety of data sets across many other missions. The Lunar Trailblazer spacecraft was designed to map surface temperature and water content on the Moon via satellite imagery. Onboard are two imagers that measure thermal and visible light bands, which must be aligned to be used in conjunction with each other as well as located precisely relative to pre‐existing topography data. To do this, we develop an algorithm which iteratively matches key features between the images, allowing for the co‐registration of data points. We test the algorithm on topography and visible imagery data from a past satellite mission and simulated data for thermal images. We show 98% accuracy and success in both imagery wavelength bands. While this was originally created for use on the Lunar Trailblazer mission, the process is applicable to future missions requiring similar functionality, and we make the code available for other users. We present a process for post‐acquisition, image‐based data localization for satellite missions with use for the Lunar Trailblazer mission We demonstrate image matching success across short‐ and mid‐wave infrared image wavelength bands and topographic hillshade data sets This IMPPAIL procedure is applicable to future missions that require higher pointing accuracy than is possible with hardware solutions We present a process for post‐acquisition, image‐based data localization for satellite missions with use for the Lunar Trailblazer mission We demonstrate image matching success across short‐ and mid‐wave infrared image wavelength bands and topographic hillshade data sets This IMPPAIL procedure is applicable to future missions that require higher pointing accuracy than is possible with hardware solutions

Abstract:

Abstract Intermittently sunlit areas near the lunar south pole are estimated to harbor thermal conditions permitting long‐term stability of water ice and other volatiles. They are targets for future science and exploration missions due to the combination of sunlight availability for solar power generation, and the possibility for extraction of volatiles for scientific analysis and ISRU. We construct a geodatabase of spatially co‐registered remote sensing and thermal model results, and perform a probabilistic analysis to determine the likelihood of successfully landing and operating on such locations for a quadrangular study area that bounds the 80°S parallel. In addition to water ice thermal stability, we consider factors relevant for the operation of solar‐powered landed spacecraft: visibility to the Earth, visibility to the sun, and local slope. For two scenarios representing sets of most‐ and least‐constrained landing site requirements, we find that circular landing ellipse diameters of ∼0.9 and 2.6 km, respectively, would allow to target available compliant terrains with 100% success. We quantify the reduction in success probability with increasing landing ellipse size. Further, we explore the distributions of geometric properties of compliant areas, and identify three sites of interest that support large areas of compliant terrain: near De Gerlache crater, near Shackleton crater, and Mons Mouton (informally named as Leibnitz‐β massif). This study is provided to support planning for future lunar missions. Plain Language Summary Researchers have identified areas near the lunar poles that receive occasional sunlight and could keep water ice and other resources stable over a long period of time. These spots are valuable for future lunar missions since they could provide solar power and possibly resources such as water for scientific study and on‐site use. To assess potential landing sites in the south polar region, we created a database combining remote sensing and thermal data set, then used it to calculate the likelihood of successful landing on accessible terrains with stable water ice conditions from the 80°S to the South Pole. The study looked at factors critical for solar‐powered landers: the terrain's visibility to Earth (for communication), sunlight access, and the slope of the ground. We analyzed two scenarios with different landing precisions. We found that landing areas with diameters of about 0.9 and 2.6 km could ensure a 100% success rate under the most‐ and least‐constrained scenarios, respectively. Larger landing areas decreased the success probability. We also mapped the physical characteristics of ideal areas and highlighted three promising locations near De Gerlache crater, Shackleton crater, and Mons Mouton. Key Points We identify intermittently sunlit areas that permit long‐term stability of sub‐surface water ice, and accessible by landed missions “Compliant terrains” in two scenarios range from 13,071 km² (least constrained) to 290 km² (most constrained) in the south polar region For areas ≥80°S, we recommend sub‐km landing precision for missions with success criteria involving exploration of lunar polar water ice

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:

The Peregrine Ion Trap Mass Spectrometer (PITMS) was a mass spectrometer designed to measure lunar gases. PITMS flew on the first flight of Astrobotic’s Peregrine lander via the Commercial Lunar Payload Services (CLPS) program in 2024 January. After launch, the lander suffered a propulsion system anomaly that prevented the mission from reaching the Moon, but PITMS collected 80 high-quality spectra while in cislunar space. PITMS observed abundant outgassing products from the Peregrine lander, including water, MON-25 oxidizer from the propulsion system leak, and traces of combustion products. PITMS data help constrain the nature of the propulsion system failure: oxidizer molecular ratios show that the leak released molecules rapidly enough for them to fully dissociate, and the high observed abundances imply that the oxidizer traveled within the lander surfaces rather than jetting into space. The amount of water offgassed by the spacecraft is substantially more than other planetary spacecraft, so the PITMS results suggest that instruments flying in the CLPS paradigm need to consider lander cleanliness. Though not successful in measuring the native lunar exosphere, the PITMS results showcase the capabilities of a mass spectrometer on board a lunar lander, along with lessons in pragmatism and flexibility that would enable such an instrument to ultimately be successful in the CLPS initiative.