DSMC analysis of Astrobotic's Peregrine Mission-1: MON-25 leak and water outgassing
      Acta Astronautica  237 (2025) 196-207
    
        
    
        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.Volcanic gas plumes’ effect on the spectrum of Venus
      Icarus  438 (2025)
    
        
    
        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.Assessing Robustness and Bias in 1D Retrievals of 3D Global Circulation Models at High Spectral Resolution: A WASP-76 b Simulation Case Study in Emission
      The Astrophysical Journal American Astronomical Society 990:2 (2025) 106
    
        
    
        Abstract:
High-resolution spectroscopy (HRS) of exoplanet atmospheres has successfully detected many chemical species and is quickly moving toward detailed characterization of the chemical abundances and dynamics. HRS is highly sensitive to the line shape and position; thus, it can detect three-dimensional (3D) effects such as winds, rotation, and spatial variation of atmospheric conditions. At the same time, retrieval frameworks are increasingly deployed to constrain chemical abundances, pressure–temperature (P–T) structures, orbital parameters, and rotational broadening. To explore the multidimensional parameter space, we need computationally fast models, which are consequently mostly one-dimensional (1D). However, this approach risks introducing interpretation bias since the planet’s true nature is 3D. We investigate the robustness of this methodology at high spectral resolution by running 1D retrievals on simulated observations in emission within an observational framework using 3D global circulation models of the quintessential HJ WASP-76 b. We find that the retrieval broadly recovers conditions present in the atmosphere, but that the retrieved P–T and chemical profiles are not a homogeneous average of all spatial and phase-dependent information. Instead, they are most sensitive to spatial regions with large thermal gradients, which do not necessarily coincide with the strongest emitting regions. Our results further suggest that the choice of parameterization for the P–T and chemical profiles, as well as Doppler offsets among opacity sources, impact the retrieval results. These factors should be carefully considered in future retrieval analyses.Plume Activity on Europa: Current Knowledge and Search Strategy for Europa Clipper
      The Planetary Science Journal IOP Publishing 6:8 (2025) 182