Weywot is the largest satellite of the candidate dwarf planet Quaoar, which also hosts a remarkable ring system located beyond its Roche limit—a configuration that challenges conventional understanding of ring dynamics. In this work, we predicted three stellar occultations by Weywot occurring in 2023 May and June, of which one was successfully observed on 2023 June 22. This multichord event took place over North America, where observers were deployed across the shadow path from Maryland to California. Five positive detections and two near misses allowed us to accurately constrain Weywot’s projected size and shape at the time of the occultation. We constrained the equivalent diameter to be between 116 and 172 km (with 95% confidence) and estimate a geometric albedo between 0.024 and 0.078—substantially lower than that of Quaoar. These results offer new insights into the physical properties of Quaoar’s system and provide valuable constraints for models of its formation and evolution.

Ground-based telescopes require useful and productive instruments to stay relevant in astronomy. The Kitt Peak Ohio State Multi-Object Spectrograph (KOSMOS), originally on the Kitt Peak National Observatory (KPNO) Mayall 4 m Telescope, is a long-slit and multi-object, low-resolution spectrograph. KOSMOS was acquired by the Astrophysical Research Consortium (ARC) for the Apache Point Observatory (APO) ARC 3.5 m telescope, implemented redesigns to the instrument, and renamed KOSMOS II. The instrument was integrated into the ARC 3.5 m's operational environment by adding a Nasmyth port adapter, a cart with a truss for mechanical support, and telescope user interface (TUI) software. Upgrades include slit-viewing guiding, internal calibration lamps, heat exhaust, and a new cryostat. Since 2021, KOSMOS II has proven capable of the high-throughput, low-resolution spectroscopy required by the ARC 3.5 m user community. This paper describes the design updates and revisions made to the instrument along with measurements of its performance. (C) 2025 Society of Photo-Optical Instrumentation Engineers (SPIE) [DOI:10.1117/1.JATIS.11.1.015003]

The shapes of asteroid phase curves are influenced by the physical properties of asteroid surfaces. The variation of an asteroid’s brightness as a function of the solar phase angle can tell us about surface properties such as grain size distribution, roughness, porosity, and composition. Phase curves are traditionally derived from photometric observations at visible wavelengths, but phase curves using infrared data can also provide useful information about an asteroid surface. Using photometric observations centered near ∼3.4 μ m from the W1 band of the Near-Earth Object Wide-field Infrared Survey Explorer mission, we construct thermally and rotationally corrected infrared phase curves for a sample of main-belt asteroids, which includes asteroids observed by the AKARI satellite, as well as subsets of the Themis and Flora dynamical families. We calculate the linear slope of the phase curves as a measure of their shape and compare W1 phase slopes to band depths of absorption features associated with hydrated materials, spectral slopes, visible albedos, W1 albedos, and diameters. We observe a steepening of the W1 phase slope of C-type asteroids with increasing 2.7 μ m band depth but little correlation between the phase slope and 3 μ m band depth or 3 μ m spectral slope. The C-types in our sample exhibit steeper average W1 phase slopes than M- or S-types, similar to visible-light phase slopes. We also observe steeper W1 phase slopes for smaller-diameter objects within the Themis family and explore comparisons to Jupiter-family comets in phase slope versus albedo space.

We present the conceptual design of a new optical echelle spectrograph for the Astrophysical Research Consortium 3.5-m Telescope at Apache Point Observatory in New Mexico. The Nasmyth-mounted slit spectrograph, intended to replace the existing echelle spectrograph that is over 20 years old, will provide continuous spectra for wavelengths spanning the range 350 nm - 1000 nm with a white pupil design featuring separate blue and red arms. A real-time slit change mechanism will allow three primary modes: 1) Resolution R similar to 32,000 for the median seeing of 1.2 arcsec FWHM, 2) R similar to 40,000 when using a smaller slit with tip-tilt image stabilization, and 3) R similar to 64,000 using a two-slice image slicer. The peak instrument throughput is similar to 38% and at 350 nm the throughput is similar to 22%. High throughput, particularly in the blue, will be enabled through the use of an atmospheric dispersion corrector, high performance coatings, tip-tilt image stabilization, and careful attention to refractive material choices. Expected instrument sensitivity for magnitude 14 stars is SNR per pixel of 50 in 3600 sec at 355 nm (u-band) and about 1800 sec for the centers of griz bands for both the R similar to 32,000 and R similar to 40,000 modes.

Jupiter's oxygen content is inextricably tied to its formation history and the evolution of the early Solar System. Recent one-dimensional thermochemical modelling of CO showed that the planet's bulk water content could be subsolar, in stark contrast to the water enrichment determined near the equator using the Juno spacecraft. Here we use a hydrodynamic model to study Jupiter's atmospheric dynamics at and below the water cloud level with simplified thermochemistry to show the effect of hydrodynamics on the abundance of disequilibrium species CO, PH3 and GeH4 in the troposphere. If PH3 and GeH4 provide only an upper limit for the oxygen abundance (<= 5 times solar), our results suggest an oxygen enrichment range of 2.5-5 times solar using updated CO thermochemistry. Using the conventional CO chemical timescale, we further reveal a correlation between moist convection and the CO abundance at the water cloud level. If such a correlation is found observationally, it would favour the formation of Jupiter near the snow line, which harbours a supersolar oxygen abundance. Numerical simulations of Jupiter's atmosphere, using gases that are tied to the deep regions of the planet, show that the amount of water that is hidden deep inside Jupiter is supersolar, with oxygen abundance between 2.5 and 5 times the solar value.

Introduction. Pluto was first identified in 1930 and since that time has completed less than 40% of its orbit (248 Earth-years). Studies of Pluto's surface composition have been ongoing for only a small subset of this period, beginning with the first evidence for CH4 (methane) ice on the surface [1] only a few years before Pluto reached equinox in 1988 and perihelion in 1989. Therefore, the majority of spectroscopic studies have taken place during northern hemisphere spring, as Pluto recedes from the Sun. Since Pluto has a ~122° obliquity and an eccentric (e=0.25) orbit, these seasonal transitions ought to be extreme [2] and potentially observable over time. Simulations of Pluto's surface evolution suggest that the entire northern hemisphere, except for Sputnik Planitia, will be devoid of volatile ices (N2, CO, CH4) by 2030 [3]. Given that in 2015 New Horizons saw extensive deposits of volatile ices in the northern hemisphere [4,5] the removal process must occur relatively rapidly, if the models are correct. The duration of the New Horizons flyby was too brief to observe large-scale changes in surface composition or ice distribution.Observations. One method for evaluating changes on Pluto on timescales of a few years while accounting for rotational variability is to obtain spectra at the same sub-observer latitude and longitude roughly a year apart [6]. This cadence is made possible by the inclination of Earth's orbit with respect to the ecliptic, which presents a limited range of sub-observer latitudes on Pluto repeating ~14 months later. In order to quantify Pluto's short-term surface changes, while correcting for its rotational variability, we designed a spectroscopic observing program specifically to make use of these “matched pairs.” Pluto was observed on 13 nights between June 2014 and August 2017 using TripleSpec, a cross-dispersed spectrograph [7] at the Apache Point Observatory’s Astrophysical Research Consortium 3.5-meter telescope. These spectra were obtained at an average resolving power of ~3500 from 0.91 to 2.47 μm. Matched pairs typically corresponded to spectra obtained in June of one year and August of the next year, at roughly the same (±10°) sub-observer longitude, avoiding opposition where the viewing geometry at small phase angles affects band depth and width [8]. Pluto’s solar phase curve is also relatively flat between phase angles of 0.5-1.5° [9], the range over which the matched pair components were acquired. Therefore, any differences in viewing geometry do not significantly affect the spectra.Analysis and Results. To evaluate changes in surface composition over time, we computed integrated band areas for the 1.16, 1.19, 1.33, 1.66, and 1.72 μm CH4 absorption features in each of the corrected nightly spectra. We also calculated shifts in the band centers for the same features as a proxy for the amount of N2 in solution with CH4 [10]. The changes in CH4 band depth and band center position for each matched pair (later date minus newer date) are presented in Figures 1 and 2, respectively. Only those changes detected at ±5-σ for band depth and ±3-σ for band center shift were considered statistically significant. The only significant changes were detected between 2014-06-17 and 2015-08-19, centered on a sub-observer longitude of ~280°, which showed an increase in CH4 band areas as well as a blueshift in the band centers. No other matched pair showed a significant change over the corresponding time period.Discussion. Due to scheduling and weather, the majority of the matched pairs were obtained of the anti-Charon hemisphere, home to the bright, volatile-rich Sputnik Planitia. However, the only sub-observer hemisphere with a statistically significant band area increase included only a small portion of Sputnik but a large portion of the low-albedo, volatile-poor Cthulhu Macula [4,5]. The sub-observer hemisphere for the 2015-08-19/2014-06-17 matched pair was unique and contained the largest fraction of Cthulhu Macula.The increase in CH4 band areas and the blueshifting of the band centers in the spectra of one unique sub-observer hemisphere between June 2014 and August 2015, and the lack of strong evidence for any decrease in band areas on any sub-observer hemisphere, points to real short-term changes in Pluto's surface composition over this time frame. The lack of significant detections on other hemispheres centered on Sputnik does not necessarily indicate a lack of changes on those hemispheres. Sputnik is a large reservoir of volatile ices that models suggest undergoes little change over a Pluto orbit [3], so the spectra of these sub-observer hemispheres should be dominated by Sputnik’s contribution, drowning out smaller changes on other areas of the surface. Conversely, the 2015-08-19/2014-06-17 sub-observer hemisphere contains a large portion of the volatile-depleted Cthulhu Macula, which would amplify the same changes in surface composition in the spectra.On the sub-observer hemispheres not dominated by Sputnik, volatile N2 and CH4 ices are present primarily in the north polar region, with alternating latitudinal bands of CH4 diluted with N2 (55-90° N and 20-35° N) and N2 diluted with CH4 (35-55° N), as measured by New Horizons in 2015, about one month prior to the second half of the 2015-08-19/2014-06-17 matched pair [5]. The observed changes in the spectra of this sub-observer hemisphere indicate both an increase in CH4 concentration and an increase in N2 concentration in the north polar regions. While this sounds contradictory, it can be achieved by preferential sublimation of more-volatile N2 from latitudes northward of 55° as Pluto approaches northern hemisphere summer, resulting in an increase in CH4 concentration in those regions, combined with deposition of that N2 onto the latitudinal band from 35-55°.References.[1] Cruikshank, D.P., et al., 1976. Science 194, 835-837. [2] Binzel, R.P., et al., 2017. Icarus 287, 30-36. [3] Bertrand, T., Forget, F., 2016. Nature 540, 86-89. [4] Grundy, W.M., et al., 2016. Science 351, aad9189. [5] Protopapa, S., et al., 2017. Icarus 287, 218-228. [6] Grundy, W.M., et al., 2013. Icarus 223, 710-721. [7] Wilson, J.C., et al., 2004. SPIE 5492, 1295-1305. [8] Pitman, K., et al., 2017. P&SS 149, 23-31. [9] Verbiscer, A., et al., 2019. EPSC-DPS2019-1261. [10] Protopapa, S., et al., 2015. Icarus 253, 179-188.

The Differential Speckle Survey Instrument (DSSI) was relocated to the Astrophysical Research Consortium 3.5 m telescope at Apache Point Observatory (APO) in early 2022. Here we present results from the first year of observations along with an updated instrument description for DSSI at APO, including a detailed description of a new internal slit mask assembly used to measure the instrument plate scale from first principles. Astrometric precision for DSSI at APO during this time was measured to be 2.06 ± 0.11 mas, with a photometric precision of 0.14 ± 0.04 mag. Results of 40 resolved binary systems are reported, including two that were previously unknown to be binaries: HIP 7535 and HIP 9603. We also present updated orbital fits for two systems: HIP 93903 and HIP 100714. Finally, we report updated or confirmed dispositions for five Kepler Objects of Interest (KOIs) that were previously explored in Colton et al., using speckle imaging to discern common proper motions pairs from line of sight companions: KOI-270, KOI-959, KOI-1613, KOI-1962, and KOI-3214AB.

Jupiter's oxygen content is inextricably tied to its formation history and the evolution of the early solar system. Recent one-dimensional thermochemical modeling of CO showed that the planet's bulk water content could be subsolar, in stark contrast to the water enrichment determined near the equator using the Juno spacecraft. Here, we use a hydrodynamic model to study Jupiter's atmospheric dynamics at and below the water cloud level with simplified CO thermochemistry to show the effect of hydrodynamics on the abundance of CO in the troposphere. Our dynamical modeling results are inconsistent with the 0.3 times solar water enrichment levels. Furthermore, we reveal a correlation between moist convection and the CO abundance at the water cloud level. If such a correlation is found observationally, subsolar water abundance can be ruled out.

The Uranian rings were discovered serendipitously on 10 March 1977 during a stellar occultation (Elliot et al., 1977a; Millis et al., 1977), and a rich set of subsequent Earth-based occultations revealed that these narrow and sharp-edged rings were eccentric and inclined, precessing under the gravitational influence of the oblate central planet. Considerable progress has been made in understanding the observed characteristics of narrow rings and sharp edges (Nicholson et al., 2018) and their associated dynamics (Longaretti, 2018), but ever since their discovery, the Uranian rings have posed dynamical puzzles that resist simple explanations. The observational basis to address these questions for the Uranus system rests largely on occultation measurements of the narrow rings spanning nearly 30 years, beginning in 1977 and concluding most recently in 2006. Nearly all of these occultation data sets are available in digital form on NASA's Planetary Data System (PDS) Ring-Moon Systems node, but many of them have not been previously published or described in detail. This paper serves as a guide to the PDS archive and provides essential information about the observations and the methods used to determine the ring widths, mean optical depths, and occultation event times from individual occultation profiles. Additional detail is provided in the Supplementary Online Material accompanying this publication. In a companion paper (French et al., 2023b), we make use of these observations to determine the Uranus ring orbits, pole direction, and gravity field, and the orbital characteristics and masses of three small Uranian moons - Cressida, Ophelia, and Cordelia - from their forced normal modes on the rings.

On 9 October 2009, multiple telescopes were used in a coordinated international observing campaign to acquire ground-based time series imaging to monitor the evolution of the impact plume from NASA's Lunar CRater Observation and Sensing Satellite (LCROSS) mission. Although standard image processing techniques applied to these data were unsuccessful at detecting the presence of any impact plume, one detection was reported after processing images with Principal Component Analysis (PCA) filtering. In this work, we develop improvements to PCA filtering that increase the signal-to-noise ratio (SNR) of plume lightcurves. We use this updated methodology to remove atmospheric seeing effects not accounted for in the previous work, such as geometric distortions. We assess the robustness of PCA filtering as we search for plume detections in observations from five additional cameras in comparison with each pixel's lightcurve during the final 40 s prior to impact to match the approximate duration of post-impact excess brightness. We explore the resulting combination of three detections and three non-detections to determine criteria for detectability in future observations of low SNR transient events. Our results indicate three observational setup constraints for optimizing the success of PCA filtering: (1) full-frame scattered light should not exceed the dynamic range between the illuminated and unilluminated surfaces, (2) the camera's analog-to-digital conversion (ADC) should use at least 16-bit resolution, and (3) the ADC should not use gamma correction. We find that poor spatial or temporal resolution do not significantly degrade detectability, which suggests that any future LCROSS-like events may be detectable in PCA-filtered amateur observations.

The conceptual design of a hybrid aerial vehicle for the exploration of the upper Venus atmosphere is presented. The vehicle will float like a balloon and harvest solar energy which is stored in batteries. The neutral buoyancy reduces the energy consumption and makes the vehicle robust and durable. Energy stored in the batteries can be used for powered flight with good horizontal and vertical mobility to explore aspects of the atmosphere. The vehicle is intended to operate near 55.3 km altitude and to explore the cloud layer of the planet. The vehicle takes its inspiration from the Stingray inflatable wing by Prospective Concepts. Based on a trade study, the wing span was set to 25 m. Equations are developed for the altitude, gas and skin temperature, and skin stress during neutrally buoyant flight. To keep the equations in a simplified analytical form, the complex compartmentalized gas pockets of the vehicle are lumped into a single gas sphere. The equations take into account the volumetric expansion of the structure and the requirement that the differential pressure needs to be large enough to allow for brief periods of powered flight without significant structural deformation. An aerodynamic analysis provides the lift and drag coefficient curves and indicates that the vehicle is pitch-stable. A powered flight analysis shows that an airspeed of 30 m/s can be maintained for 31 min at 55 km and 69 min at 69 km altitude.

The conceptual design of a hybrid aerial vehicle for the exploration of the upper Venus atmosphere is discussed. The vehicle is intended to be inflatable such that it fits into the aeroshell of an atmospheric entry vehicle. The vehicle will be buoyant enough to maintain altitude without expending energy. In powered forward flight, it will generate sufficient aerodynamic lift to explore interesting aspects of the atmosphere. The flow over the vehicle in forward flight was analyzed with the XFLR5, VSPAERO, and Fluent software. While XFLR5 and VSPAERO are design methods, Fluent allows for both inviscid solutions and Reynolds-averaged Navier-Stokes calculations with k-epsilon turbulence model and wall function. An inflatable scaled wind tunnel model was designed and built to gain experience with the more practical aspects of inflatable vehicles that exploit aerodynamic lift. The model was tested in the low-speed wind tunnel at New Mexico State University. Finally, two different propeller designs that mimic propellers seen on terrestrial airships, were analyzed with JBlade, which is based on blade element momentum theory.

Planetary caves are desirable environments for the search for biosignatures corresponding to extant or extinct extraterrestrial life due to the protection they offer from surface-level solar radiation and ionizing particles. Near-infrared (NIR) reflectance spectroscopy is one of a multitude of techniques that, when taken together, can provide a comprehensive understanding of the geomicrobiology in planetary subsurface regions. To that end, we developed two portable NIR spectrometers that employ acousto-optic tunable filters and demonstrated them in three geochemically distinct cave environments. The instruments were deployed both as stand-alone spectrometers positioned against the targets manually and as a component of an instrument payload mounted on a quadruped robot capable of vertical excursions of several meters. In situ measurements of calcium carbonates, sulfates, metal oxides, and microbial colonies and mats revealed spectral signatures that enable a distinction between the targets of interest and the underlying substrates. The ruggedness and portability of the instruments, and their low size, weight, and power, spectral agility, and active illumination make AOTF-based spectrometers ideally suited for studies of planetary caves.

Published near-IR spectra of the four largest classical Uranian satellites display the presence of discrete deposits of CO _2 ice, along with subtle absorption features around 2.2 μ m. The two innermost satellites, Miranda and Ariel, also possess surfaces heavily modified by past endogenic activity. Previous observations of the smallest satellite, Miranda, have not detected the presence of CO _2 ice, and a report of an absorption feature at 2.2 μ m has not been confirmed. An absorption feature at 2.2 μ m could result from exposed or emplaced NH _3 - or NH _4 -bearing species, which have a limited lifetime on Miranda’s surface, and therefore may imply that Miranda’s internal activity was relatively recent. In this work, we analyzed near-IR spectra of Miranda to determine whether CO _2 ice and the 2.2 μ m feature are present. We measured the band area and depth of the CO _2 ice triplet (1.966, 2.012, and 2.070 μ m), a weak 2.13 μ m band attributed to CO _2 ice mixed with H _2 O ice, and the 2.2 μ m band. We confirmed a prior detection of a 2.2 μ m band on Miranda, but we found no evidence for CO _2 ice, either as discrete deposits or mixed with H _2 O ice. We compared a high signal-to-noise-ratio spectrum of Miranda to synthetic and laboratory spectra of various candidate compounds to shed light on what species may be responsible for the 2.2 μ m band. We conclude that the 2.2 μ m absorption is best matched by a combination of NH _3 ice with NH _3 hydrates or NH _3 –H _2 O mixtures. NH _4 -bearing salts like NH _4 Cl are also promising candidates that warrant further investigation.

Lunar water ice can be broadly categorized as belonging to one of two populations: deep, ancient, stable deposits, and shallow, transient, recent deposits. However, a third state for lunar ice is also possible. Temporary sequestration occurs when ice is deposited into a transiently shadowed region at the lunar poles. These temporarily sequestered ice deposits are unstable over geologic time scales, but in the short term, are capable of a wide range of migration, sublimation, and retention patterns due to their thermally dependent sublimation and migration rates. We developed a model to characterize the range of possible migration and retention behaviors for temporarily sequestered ice deposits within locations with dynamic illumination conditions. We found that water ice migration, sublimation, and retention varies across the lunar polar environment, with neighboring locations experiencing different illumination and thermal conditions. We found that the residence times of temporarily sequestered ice deposits in some high latitude, non‐shadowed regions can be similar to or greater than the length of time spent above the long term stability temperature of ice during lunar winter months, leading to incomplete removal of surface or near surface ice during the day. We also found that shallowly buried, unstable ice deposits take longer to sublimate than surface deposits, leading to a temporal lag in escaping ice. This work suggests that temporary sequestration can lead to complex ice migration and retention patterns at high latitudes, with ice sublimation efficiency varying across the lunar polar environment due to local, small scale differences in illumination conditions.

In this work we present the results of a spectral observing campaign of Pluto to search for temporal changes in surface composition on 1- to 3-year timescales. Near-infrared spectra of Pluto were obtained from June 2014 to August 2017 with the TripleSpec cross-dispersed spectrograph at the Apache Point Observatory's 3.5-meter Astrophysical Research Consortium (ARC) telescope. Observations were requested in order to obtain spectra of approximately the same sub-observer hemisphere ∼14 months apart, thus removing the effects of viewing geometry and rotation phase. Comparison of the CH4 (methane) band areas and band center shifts between each component of these "matched pairs" revealed a surface in transition. Band areas for the 1.66 and 1.72μm CH4 absorption features exhibited a >5-σ increase between 2014-06-17 and 2015-08-19, corresponding to a sub-observer hemisphere centered at ∼280°E, with the latter date only 1 month after the New Horizons flyby of Pluto. The majority of matched pairs were obtained of the anti-Charon hemisphere, home to the bright, volatile-rich Sputnik Planitia, and did not present statistically significant changes in CH4 band areas. CH4 band center shifts, which provide information on the mixing state of CH4 and N2 in solid solution, were calculated between components of each matched pair, with no significant band shifts detected. The favored explanation for these combined results is the sublimation of more-volatile N2 from the northern latitudes of Pluto in the lead-up to northern hemisphere summer solstice in 2029, leading to an increase in CH4 concentration.

Europa’s surface composition and evidence for cryovolcanic activity can provide insight into the properties and composition of the subsurface ocean, allowing the evaluation of its potential habitability. One promising avenue for revealing the surface processing and subsurface activity are the relative fractions of crystalline and amorphous water-ice observed on the surface, which are influenced by temperature, charged particle bombardment, vapor deposition, and cryovolcanic activity. The crystallinity observed on Europa’s leading hemisphere cannot be reproduced by thermophysical and particle flux modeling alone, indicating that there may be additional processes influencing the surface. We performed a spectral mixture analysis on hyperspectral image cubes from the Galileo Near-Infrared Mapping Spectrometer (NIMS) to identify how surface crystallinity is influenced by physical processing at a high spatial resolution scale. We focus specifically on two image cubes, 15e015 closer to the equator and 17e009 closer to the south pole, both on the leading hemisphere. We performed a nonnegative least-squares spectral mixture analysis to reveal both the non-ice composition and the water-ice crystallinity of the surface. We found that amorphous water-ice dominates the spectrum at the equator and the south pole. We estimated a mean crystallinity of ∼35% within the 15e015 NIMS cube and a mean crystallinity of ∼15% within the 17e009 NIMS cube, which is consistent with ground-based spectroscopically derived crystallinities. We also identified a correlation of magnesium sulfate, magnesium chloride, and hydrated sulfuric acid with lineae and ridges, which may provide evidence for surface processing by upwelling subsurface material.

While there have been far fewer missions to the outer Solar System than to the inner Solar System, spacecraft destined for the giant planets have conducted a wide range of fundamental investigations, returning data that continues to reshape our understanding of these complex systems, sometimes decades after the data were acquired. These data are preserved and accessible from national and international planetary science archives. For all NASA planetary missions and instruments the data are available from the science discipline nodes of the NASA Planetary Data System (PDS). Looking ahead, the PDS will be the primary repository for giant planets data from several upcoming missions and derived datasets, as well as supporting research conducted to aid in the interpretation of the remotely sensed giant planets data already archived in the PDS.

This archive contains the raw data and data products from observations of the 2009-10-09 impact of the Lunar CRater Observation and Sensing Satellite (LCROSS) spacecraft on the Moon by the StellaCam instrument on the Apache Point Observatory NMSU 1m telescope. Full details about the raw data are available in Chanover, N. J. et al. Results from the NMSU-NASA Marshall Space Flight Center LCROSS observational campaign. J. Geophys. Res. (Planets) 116, E08003 (2011). https://doi.org/10.1029/2010JE003761 We use principal component analysis (PCA) filtering both to coregister the raw time series and to effectively remove a static background signal that is spatially and temporally modified by atmospheric and instrumental effects. We iteratively remove principal components from the data through cumulative sequential elimination (CSE) resulting in a non-detection of the LCROSS ejecta plume signal. Full details are available in the published journal article: Strycker, Paul D., Nancy J. Chanover, Ruth L. Temme, Jonathan M. Schotte, Payton L. Mueller, and Emily L. Karls. 2023. "Time Series Analysis Methods and Detectability Factors for Ground-Based Imaging of the LCROSS Impact Plume" Remote Sensing 15, no. 1: 37. https://doi.org/10.3390/rs15010037 This work was supported by NASA’s Lunar Data Analysis Program through grant number NNX15AP92G.