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SSOLVE is a heterodyne spectrometer that is under development as a technology demonstration for future lunar lander missions. The system contains a heliostat to target the Sun, optics, and submillimeter-wave, and Terahertz (THz) receivers to measure the column abundance of H 2 O, OH, and HDO.

Advances in optical testing are as important as advances in fabrication because one can make only what one can measure. A high-precision metrology capability is utilized to close the gap between interferometric testing and lower precision metrology, laser radar, or contact-probe-based coordinate measuring machines (CMM) to accurately measure surfaces with large form error. This nearly universal optical testing method employs a precision CMM equipped with a non-contact, confocal probe. This technique was developed to characterize and align a broad spectrum of optical surfaces including ones with high slopes that are nearly impossible to measure using traditional interferometric testing without custom-made optics. Optical components covering a wide range of prescriptions, such as large convex conics, high-sloped aspherics, grazing-incidence x-ray optics, and highly deformed flats, were successfully measured. The resulting data were processed using custom-developed routines to determine the optic’s alignment, the departure from design surface, and the as-built prescription parameters. This information was used to verify and guide the development and fabrication of novel optics.

Laser Induced Breakdown Spectroscopy (LIBS) in the Ultra Violet/Visible/Near-IR (UVN) spectral range is a powerful analytical tool that facilitates the interpretation of Raman spectroscopic data by providing additional details in elemental chemistry. To acquire the complete information of molecular vibrations for more accurate and precise chemical bonding and structural analysis, an ideal

The surface of ice satellites with known subsurface oceans (e.g., Europa, Ganymede, Callisto, Enceladus and Titan) are likely to contain the compositional imprints of the underlying interior ocean and their radiation processed products [1][2]. For instance, the community consensus is that Europa harbors liquid water beneath an icy crust, which has raised the possibility that life, or conditions favorable for life exist. Here we present the evolution of a powerful instrument “In situ Chemistry Experiment - μscope, Photoluminescence and Raman OBservations on Icy Satellites (ICE-μPROBIS),” a derivative of an instrument [3] proposed for a past NASA ROSES ICEE-2 AO, that can detect life biosignatures. The current Europa Lander Mission concept [4] with its advanced sample collection and analysis system, will be a blueprint for future lander/rover missions to other ocean worlds. ICE-μPROBIS instrument onboard the next generation of lander or rover mission will provide the unprecedented opportunity to carry out time-resolved Raman and photoluminescence (PL) spectroscopy, of ice samples collected from the surface, to discover if present, the types and distribution of biotic and abiotic organic compounds, measure CHNOPS containing organics and minerals and correlate them to radiolysis processed and textural features. ICE-µPROBIS includes an optical microscope to provide context imaging for the spectroscopy. Here, we describe ICE-μPROBIS’s capabilities and discuss time-resolved Raman and luminescence spectra of amino acids [5], PAHs [6] and, hydrated sulfates minerals and sulfuric acid [7] on the surface and subsurface of water-ice samples. Fig. 1. ICE-μPROBIS concept and system block diagram. ICE-µPROBIS enables in situ, spatially resolved and highly sensitive detection and characterization of organics and minerals from samples collected from icy satellite surface and near subsurface. Fig. 2. ICE-μPROBIS enables measurement of Raman spectra of the four aromatic amino acids at 5 m distance, L-phenylalanine (Phe), L-tyrosine (Tyr), L-tryptophan (Trp), L-histidine (His), and one aliphatic amino acid L-proline (Pro) [5]. Fig. 3. Standoff (120 m) TR-Raman spectra of Napthalene (PAH) inside water ice. ICE-μPROBIS will provide new insight into icy satellite surface processes by obtaining detailed analyses of surface composition. It can be used to identify key radiation products and structural changes in the sample, thus providing an indication of the extent of chemical and physical change and an estimate of the resurfaced age of the ice [6]. Fig. 4. Remote TR-Raman spectra at a distance of 5 m: a) ice nodules of 1 M sulfuric acid (H2SO4), and b) particulate ice solution of 3% hydrogen peroxide (H2O2) in distilled H2O in a lighted laboratory setting [7]. [1] Brown, M. E., et al., (2013). The Astronomical Journal, 145(4) [2] Vance, S. D., et al., (2021). Journal of Geophysical Research: Planets, 126, e2020JE006736. [3] Aslam, S., et al., (2020). AGU – iPosterSessions.com. Available online: https://www.researchgate.net/publication/346654802 [4] https://www.lpi.usra.edu/opag/meetings/opag2020fall/presentations/Hand_6014.pdf [5] Acosta-Maeda, T., (2016). Ph.D. Dissertation, https://scholarspace.manoa.hawaii.edu/bitstream/10125/51470/2016-08-phd-acostamaeda_uh.pdf [6] Sharma, S. K., et al. (2020). J. Raman Spectrosc. 51, 1782-1793. https://doi.org/10.1002/jrs.5814 [7] Sandford, M., (2020). PhD Dissertation, https://www.soest.hawaii.edu/gg/academics/theses/Sandford_Dissertation.pdf

Icy worlds of the outer solar system contain tantalizing evidence of habitability and potential life. These bodies also present extra exploration challenges due to the harsh environmental conditions at the surfaces. Thus, robust and reliable detectors are necessary for the in situ spectroscopic identification of astrobiologically relevant compounds deposited on the icy surface, entrained in thick atmospheres, or rafted in plumes. In addition, the distinction between prebiotic, extant, and relict organic molecules in such environments is needed to address life detection goals. The Ultra-Violet Detector Innovation for Raman Exploration and CharacTerization (UV-DIRECT) of ocean worlds project focuses on the development SiC- avalanche photodiode (APD) technology for UV-Raman spectroscopy and Raman imaging. Si-based Single Photon Avalanche Diodes (SPADs) have been developed for time resolved Raman spectroscopy in recent years, but SiC (Silicon Carbide) APD detectors have advantages over them. Our detector is an ultra-compact, radiation and temperature tolerant, visible blind device that has high quantum efficiency (QE) in the DUV (~260 nm) but poorer performance in the near ultraviolet (NUV) between 300-340nm that is important for Raman Spectroscopy. Our approach to improve this combines a series of numerical models with laboratory testing to enhance the QE response and ultimately the single photon detection efficiency in the NUV (~340 nm). Raman spectroscopy has established itself in current missions as an information-rich, non-contact, non-destructive method for identifying and characterizing inorganic and organic compounds in a wide variety of planetary materials. UV/NUV-Raman spectroscopy is well-suited to characterizing plume materials and surface ice deposits, since it especially sensitive to organic compounds and inorganic salts improved sensitivity due to the combination of resonance effects and the lack of background fluorescence and less risk of sample damage compared to excitation with wavelengths Figure 1. UV-DIRECT is based on SiC-APD technology with the goal of pushing the capabilities of UV-Raman spectroscopy and Raman imaging for the exploration of icy worlds.

A proof-of-concept, compact, portable Fourier Ptychographic Microscope (FPM) to perform wide field-of-view, high spatial resolution imaging (

Raman spectroscopy and laser induced breakdown spectroscopy (LIBS) are complementary techniques that together can provide a comprehensive characterization of geologic environments. For landed missions with constrained access to target materials on other planetary bodies, discerning signatures of life and habitability can be daunting, particularly where the preservation of organic compounds that contain the building blocks of life is limited. The main challenge facing any spectroscopy measurements of natural samples is the complicated spectra that often contain signatures for multiple components, particularly in rocks that are composed of several minerals with surfaces colonized by microbes. The goal of this study was to use the combination of Raman spectroscopy and LIBS to discern different environmental regimes based on the identification of minerals and biomolecules in rocks and sediments. Iceland is a terrestrial volcano-glacial location that offers a range of planetary analog environments, including volcanically active regions, extensive lava fields, geothermal springs, and large swaths of ice-covered terrain that are relevant to both rocky and icy planetary bodies. We combined portable VIS (532 nm) and NIR (785 nm) Raman spectroscopy, VIS micro-Raman spectroscopic mapping, and UV/VIS/NIR (200 – 1000 nm) and Mid-IR (5.6 – 10 μm, 1785 – 1000 cm−1) laser induced breakdown spectroscopy (LIBS) to characterize the mineral assemblages, hydrated components, and biomolecules in rock and sediment samples collected from three main sites in the volcanically active Kverkfjoll-Vatnajokull region of Iceland: basalt and basalt-hosted carbonate rind from Hveragil geothermal stream, volcanic sediments from the base of Vatnajokull glacier at Kverkfjoll, and lava from the nearby Holuhraun lava field. With our combination of techniques, we were able to identify major mineral polytypes typical for each sample set, as well as a large diversity of biomolecules typical for lichen communities across all samples. The anatase we observed using micro-Raman spectroscopic mapping of the lava compared with the volcanic sediment suggested different formation pathways: lava anatase formed authigenically, sediment anatase could have formed in association with microbial weathering. Mn-oxide, only detected in the carbonate samples, seems to have two possible formation pathways, either by fluvial or microbial weathering or both. Even with our ability to detect a wide diversity of biomolecules and minerals in all of the samples, there was not enough variation between each set to distinguish different environments based on the limited measurements done for this study.

A systematic calibration approach is presented to correlate the digital output of an infrared camera and the scene temperature. Aided by the optoelectronic properties of the camera, as few as two experimental data points are needed to establish this correlation. This approach can readily include the effects of atmospheric transmission, scene emissivity, and different background subtractions. Hence, the temperature conversion in flight can be reliably obtained from laboratory calibration. The conversion function can also be used to identify the camera’s thermal sensitivity and temperature resolution, which are important information in different space missions. In applying this calibration procedure to a laboratory camera and the compact thermal imager onboard the International Space Station, its validity is confirmed.

Multispectral snapshot imagers are capable of producing 2-D spatial images with a single exposure at selected, numerous wavelengths using the same camera, therefore, operate differently from push broom or whiskbroom imagers. They are payloads of choice in multi-angular, multi-spectral imaging missions that use small satellites flying in controlled formation, to retrieve Earth science measurements dependent on the target’s bidirectional reflectance-distribution function. Narrow fields of view are needed to capture images with moderate spatial resolution. This paper quantifies the dependencies of the imager’s optical system, spectral elements, and camera on the requirements of the formation mission and their impact on performance metrics, such as spectral range, swath, and signal-to-noise ratio (SNR). All variables and metrics have been generated from a comprehensive, payload design tool. The baseline optical parameters selected (a diameter of 7 cm, a focal length of 10.5 cm, a pixel size of $20~\mu \text{m}$ , and a field of view of 1.15°) and snapshot imaging technologies are available. The spectral components shortlisted were waveguide spectrometers, acousto-optic tunable filters (AOTF), electronically actuated Fabry–Perot interferometers, and integral field spectrographs. Qualitative evaluation favored AOTFs, because of their low weight, small size, and flight heritage. Quantitative analysis showed that the waveguide spectrometers perform better in terms of achievable swath (10–90 km) and SNR (>20) for 86 wavebands, but the data volume generated will need very high bandwidth communication to downlink. AOTFs meet the external data volume caps well as the minimum spectral (wavebands) and radiometric (SNR) requirements, therefore, are found to be currently feasible and design changes to improve swath suggested.

The design of an advanced Net Flux Radiometer (NFR), for inclusion as a payload on a future Ice Giants probe mission, is given. The Ice Giants NFR (IG-NFR) will measure the upward and downward radiation flux (hence net radiation flux), in seven spectral bands, spanning the range from solar to far infra-red wavelengths, each with a 5° Field-Of-View (FOV) and in five sequential view angles (±80°, ±45°, and 0°) as a function of altitude. IG-NFR measurements within either Uranus or Neptune’s atmospheres, using dedicated spectral filter bands will help derive radiative heating and cooling profiles, and will significantly contribute to our understanding of the planet’s atmospheric heat balance and structure, tropospheric 3-D flow, and compositions and opacities of the cloud layers. The IG-NFR uses an array of non-imaging Winston cones integrated to a matched thermopile detector Focal Plane Assembly (FPA), with individual bandpass filters, housed in a diamond windowed vacuum micro-vessel. The FPA thermopile detector signals are read out in parallel mode, amplified and processed by a multi-channel digitizer application specific integrated circuit (MCD ASIC) under field programmable gate array (FPGA) control. The vacuum micro-vessel rotates providing chopping between FOV’s of upward and downward radiation fluxes. This unique design allows for small net flux measurements in the presence of large ambient fluxes and rapidly changing ambient temperatures during the probe descent to ≥10 bar pressure.

We describe a novel mission architecture to investigate the lower atmosphere of Saturn's moon, Titan. Titan is the only moon in the solar system to possess a dense atmosphere, which has important similarities to, and differences from, the Earth. Like Earth, Titan has lakes and seas on its surface [1] - although these are composed of liquid hydrocarbons and not water [2], [3]. The proposed mission concept is comprised of two elements: (1) A small satellite module (PCV, Probe Carrier Vehicle) that is deployed from a host Saturn system mission spacecraft, which can be a NASA small or medium class mission (either Discovery or New Frontiers mission class) and acts as a carrier and data relay for the entry probes; (2) Four atmospheric entry probes (EP), one per $\sim 10^{\mathrm{o}}$ latitude from 60-90 °N, that aerobrake and descend under parachute from $\sim 135$ km to the surface, measuring profiles of temperature, winds and gas composition during the descent. Multiple probes at different latitudes are required to constrain the spatial variation in cloud formation, precipitation and the implications for lake composition. The mission concept would require a ride-share to reach the Saturn system. Currently three of the seven anticipated New Frontiers mission destinations are in the Saturn System: Saturn Probe, Enceladus and Titan itself. The TEAM (Titan Exploration Atmospheric Microprobes) mission concept is designed to be largely independent once deployed in the Saturn system, however the prime mission spacecraft (either New Frontiers or Discovery class mission) will provide the data relay from the PCV to the Earth. Key mission challenges include thermal management and probe release and navigation.

Here we describe the Primitive Object Volatile Explorer (PrOVE), a smallsat mission concept to study the surface structure and volatile inventory of comets in their perihelion passage phase when volatile activity is near peak. CubeSat infrastructure imposes limits on propulsion systems, which are compounded by sensitivity to the spacecraft disposal state from the launch platform and potential launch delays. We propose circumventing launch platform complications by using waypoints in space to park a deep space SmallSat or CubeSat while awaiting the opportunity to enter a trajectory to flyby a suitable target. In our Planetary Science Deep Space SmallSat Studies (PSDS3) project, we investigated scientific goals, waypoint options, potential concept of operations (ConOps) for periodic and new comets, spacecraft bus infrastructure requirements, launch platforms, and mission operations and phases. Our payload would include two low-risk instruments: a visible image (VisCAM) for 5-10 m resolution surface maps; and a highly versatile multispectral Comet CAMera (ComCAM) will measure 1) H2O, CO2, CO, and organics non-thermal fluorescence signatures in the 2-5 μm MWIR, and 2) 7-10 and 8-14 μm thermal (LWIR) emission. This payload would return unique data not obtainable from ground-based telescopes and complement data from Earth-orbiting observatories. Thus, the PrOVE mission would (1) acquire visible surface maps, (2) investigate chemical heterogeneity of a comet nucleus by quantifying volatile species abundance and changes with solar insolation, (3) map the spatial distribution of volatiles and determine any variations, and (4) determine the frequency and distribution of outbursts.

Ground-based heterodyne spectroscopy is used to observe the night side of Venus by probing single pressure broadened CO2 absorption lines. From the pressure induced line broadening, the predominant temperature at different altitude layers can be deduced. It is found, that heterodyne spectroscopy is sensitive to probe the mesosphere between ~ 60 km and 90 km with an altitude resolution of ~ 4.5 km . During two observing campaigns in March and May 2012, four different locations on the planet were investigated. Herein, we report on the retrieval of vertical temperature profiles in the nightside atmosphere of Venus. Retrieval of atmospheric parameters is based on a Levenberg–Marquard χ2 optimization that iteratively compares observed data to telluric transmittance corrected Venus׳ top-of-atmosphere spectra calculated using a radiative transfer algorithm. The deduced profiles are compared to the Venus International Reference Atmosphere and some found to be in satisfactory agreement. Sub-Doppler resolution Infrared heterodyne observations can provide temperature measurements that complement existing sub-mm and space based observations.

Terrestrial groundbased spectroscopy of Mars at subsolar latitude in October 2007 (southern summer, Mars year 28) reveals variability in the depth of a spectral absorption feature from a carbon dioxide isotopologue, 16O12C18O (‘628 CO2’), which correlates with increasing surface temperature in the early afternoon of the Martian sol. The correlation suggests a fractionation process that depletes isotopically heavy CO2 from the atmosphere by surface adsorption at night and restores atmospheric enrichment during the day through thermal desorption. Measurements reported here yield a depleted condition at noon, with 18O depleted to −92 ± 23‰ relative to a terrestrial isotopic standard (VSMOW, Vienna Standard Mean Ocean Water), increasing to +71 ± 18‰ at 13:19 LST, over a temperature increase from 266.9 K to 275.4 K. The average is +9 ± 14‰, consistent with results from landers and remote spectroscopy that averaged data collected over a broad range of daylight local times to obtain an average close to the terrestrial standard. Past measurements of CO2 isotopologues have been inconsistent with each other and in some cases inconsistent with predicted enrichment in heavy isotopes, with some measurements even slightly depleted in heavy isotopes. Local solar time of a measurement thus may skew this important constraint on estimating the density of the primordial atmosphere, although seasonal polar temperature variation also may have a substantial influence.

The design of a versatile dual-telescope thermal-infrared radiometer spanning the spectral wavelength range 8–200 µm, in five spectral pass bands, for outer planet fly-by missions is described. The dual-telescope design switches between a narrow-field-of-view and a wide-field-of-view to provide optimal spatial resolution images within a range of spacecraft encounters to the target. The switchable dual-field-of-view system uses an optical configuration based on the axial rotation of a source-select mirror along the optical axis. The optical design, spectral performance, radiometric accuracy, and retrieval estimates of the instrument are discussed. This is followed by an assessment of the surface coverage performance at various spatial resolutions by using the planned NASA Europa Mission 13-F7 fly-by trajectories as a case study.

We report temperatures in Venus’ upper mesosphere/lower thermosphere, deduced from reanalyzing very high resolution infrared spectroscopy of CO2 emission lines acquired in 1990 and 1991. Kinetic temperatures at ∼110 km altitude (0.15 Pa) are derived from the Doppler width of fully-resolved single line profiles measured near 10.4 μm wavelength using the NASA GSFC Infrared Heterodyne Spectrometer (IRHS) at the NASA IRTF on Mauna Kea, HI, close to Venus inferior conjunction and two Venus solstices. Measured temperatures range from ∼200 to 240 K with uncertainty typically less than 10 K. Temperatures retrieved from similar measurement in 2009 using the Cologne Tuneable Heterodyne Infrared Spectrometer (THIS) at the NOAO McMath Telescope at Kitt Peak, AZ are 10–20 K lower. Temperatures retrieved more recently from the SOIR instrument on Venus EXpress are consistent with these results when the geometry of observation is accounted for. It is difficult to compare ground-based sub-mm retrievals extrapolated to 110 km due to their much larger field of view, which includes the night side regions not accessible to infrared heterodyne observations. Temperature variability appears to be high on day-to-day as well as longer timescales. Observed short term and long term variability may be attributed to atmospheric dynamics, diurnal variability and changes over solar activity and seasons. The Venus International Reference Atmosphere (VIRA) model predicts cooler temperatures at the sampled altitudes in the lower thermosphere/upper mesosphere and is not consistent with these measurements.

NASA's EPOXI mission observed the disc-integrated Earth and Moon to test techniques for reconnoitering extrasolar terrestrial planets, using the Deep Impact flyby spacecraft to observe Earth at the beginning and end of Northern Hemisphere spring, 2008, from a range of ∼1/6 to 1/3 AU. These observations furnish high-precision and high-cadence empirical photometry and spectroscopy of Earth, suitable as "ground truth" for numerically simulating realistic observational scenarios for an Earth-like exoplanet with finite signal-to-noise ratio. Earth was observed at near-equatorial sub-spacecraft latitude on 18-19 March, 28-29 May, and 4-5 June (UT), in the range of 372-4540 nm wavelength with low visible resolving power (λ/Δλ=5-13) and moderate IR resolving power (λ/Δλ=215-730). Spectrophotometry in seven filters yields light curves at ∼372-948 nm filter-averaged wavelength, modulated by Earth's rotation with peak-to-peak amplitude of ≤20%. The spatially resolved Sun glint is a minor contributor to disc-integrated reflectance. Spectroscopy at 1100-4540 nm reveals gaseous water and carbon dioxide, with minor features of molecular oxygen, methane, and nitrous oxide. One-day changes in global cloud cover resulted in differences between the light curve beginning and end of ≤5%. The light curve of a lunar transit of Earth on 29 May is color-dependent due to the Moon's red spectrum partially occulting Earth's relatively blue spectrum. The "vegetation red edge" spectral contrast observed between two long-wavelength visible/near-IR bands is ambiguous, not clearly distinguishing between the verdant Earth diluted by cloud cover versus the desolate mineral regolith of the Moon. Spectrophotometry in at least one other comparison band at short wavelength is required to distinguish between Earth-like and Moon-like surfaces in reconnaissance observations. However, measurements at 850 nm alone, the high-reflectance side of the red edge, could be sufficient to establish periodicity in the light curve and deduce Earth's diurnal period and the existence of fixed surface units.

Infrared spectroscopy sensitive to thermal emission from Jupiter’s stratosphere reveals effects persisting 23 days after the impact of a body in late July 2009. Measurements obtained on 2009 August 11 UT at the impact latitude of 56°S (planetocentric), using the Goddard Heterodyne Instrument for Planetary Wind and Composition mounted on the NASA Infrared Telescope Facility, reveal increased ethane abundance and the effects of aerosol opacity. An interval of reduced thermal continuum emission at 11.744 μm is measured ∼60–80° towards planetary east of the impact site, estimated to be at 305° longitude (System III). Retrieved stratospheric ethane mole fraction in the near vicinity of the impact site is enhanced by up to ∼60% relative to quiescent regions at this latitude. Thermal continuum emission at the impact site, and somewhat west of it, is significantly enhanced in the same spectra that retrieve enhanced ethane mole fraction. Assuming that the enhanced continuum brightness near the impact site results from thermalized aerosol debris blocking contribution from the continuum formed in the upper troposphere and indicating the local temperature, then continuum emission by a haze layer can be approximated by an opaque surface inserted at the 45–60 mbar pressure level in the stratosphere in an unperturbed thermal profile, setting an upper limit on the pressure and therefore a lower limit on the altitude of the top of the impact debris at this time. The reduced continuum brightness east of the impact site can be modeled by an opaque surface near the cold tropopause, which is consistent with a lower altitude of ejecta/impactor-formed opacity. The physical extent of the observed region of reduced continuum implies a minimum average velocity of 21 m/s transporting material prograde (planetary east) from the impact.

The Cassini Huygens mission provides a unique opportunity to combine ground-based and spacecraft investigations to increase our understanding of chemical and dynamical processes in Titan’s atmosphere. Spectroscopic measurements from both vantage points enable retrieving global wind structure, temperature structure, and atmospheric composition. An updated analysis of Titan data obtained with the NASA Goddard Space Flight Center’s Infrared Heterodyne Spectrometer (IRHS) and Heterodyne Instrument for Planetary Wind and Composition (HIPWAC) prior to and during the Cassini Huygens mission is compared to retrievals from measurements with the Cassini Composite Infrared Spectrometer (CIRS). IRHS/HIPWAC results include the first direct stratospheric wind measurements on Titan, constraints on stratospheric temperature, and the study of atmospheric molecular composition. These results are compared to CIRS retrievals of wind and temperature profile from thermal mapping data and ethane abundance at 10–15° South latitude, near the equatorial region. IRHS/HIPWAC wind results are combined with other direct techniques, stellar occultation measurements, and CIRS results to explore seasonal variability over nearly one Titan year and to provide an empirical altitude profile of stratospheric winds, varying from ∼50 to 210 m/s prograde. The advantage of fully resolved line spectra in species abundance measurements is illustrated by comparing the possible effect on retrieved ethane abundance by blended spectral features of other molecular constituents, e.g., acetylene (C2H2), ethylene (C2H4), allene (C3H4), and propane (C3H8), which overlap the ν9 band of ethane, and are not resolved at lower spectral resolution. IR heterodyne spectral resolution can discriminate weak spectral features that overlap the ν9 band of ethane, enabling ethane lines alone to be used to retrieve abundance. Titan’s stratospheric mean ethane mole fraction (8.6±3 ppmv) retrieved from IRHS/HIPWAC emission line profiles (resolving power λ⧸Δλ∼106) is compared to past values obtained from lower resolution spectra and from CIRS measurements (resolving power λ⧸Δλ∼2×103) and more compatible recent analysis. Results illustrate how high spectral resolution ground-based studies complement the spectral and spatial coverage and resolution of moderate spectral resolution space-borne spectrometers.

We have obtained high-resolution spectra of Jupiter's Great Red Spot (GRS) between 4.6 and 5.4 microns using telescopes on Mauna Kea in order to derive gas abundances and to constrain its cloud structure between 0.5 and 5~bars. We used line profiles of deuterated methane CH3D at 4.66 microns to infer the presence of an opaque cloud at 5+/-1 bar. From thermochemical models this is almost certainly a water cloud. We also used the strength of Fraunhofer lines in the GRS to obtain the ratio of reflected sunlight to thermal emission. The level of the reflecting layer was constrained to be at 570+/-30 mbar based on fitting strong ammonia lines at 5.32 microns. We identify this layer as an ammonia cloud based on the temperature where gaseous ammonia condenses. We found evidence for a strongly absorbing, but not totally opaque, cloud layer at pressures deeper than 1.3 bar by combining Cassini/CIRS spectra of the GRS at 7.18 microns with ground-based spectra at 5 microns. This is consistent with the predicted level of an NH4SH cloud. We also constrained the vertical profile of water and ammonia. The GRS spectrum is matched by a saturated water profile above an opaque water cloud at 5~bars. The pressure of the water cloud constrains Jupiter's O/H ratio to be at least 1.1 times solar. The ammonia mole fraction is 200+/-50ppm for pressures between 0.7 and 5 bar. Its abundance is 40 ppm at the estimated pressure of the reflecting layer. We obtained 0.8+/-0.2 ppm for PH3, a factor of 2 higher than in the warm collar surrounding the GRS. We detected all 5 naturally occurring isotopes of germanium in GeH4 in the Great Red Spot. We obtained an average value of 0.35+/-0.05 ppb for GeH4. Finally, we measured 0.8+/-0.2 ppb for CO in the deep atmosphere., 24 pages, 22 figures

We present time series photometry of the M dwarf transiting exoplanet system GJ 436 obtained with the the EPOCh (Extrasolar Planet Observation and Characterization) component of the NASA EPOXI mission. We conduct a search of the high-precision time series for additional planets around GJ 436, which could be revealed either directly through their photometric transits, or indirectly through the variations these second planets induce on the transits of the previously known planet. In the case of GJ 436, the presence of a second planet is perhaps indicated by the residual orbital eccentricity of the known hot Neptune companion. We find no candidate transits with significance higher than our detection limit. From Monte Carlo tests of the time series, we rule out transiting planets larger than 1.5 R_Earth interior to GJ 436b with 95% confidence, and larger than 1.25 R_Earth with 80% confidence. Assuming coplanarity of additional planets with the orbit of GJ 436b, we cannot expect that putative planets with orbital periods longer than about 3.4 days will transit. However, if such a planet were to transit, we rule out planets larger than 2.0 R_Earth with orbital periods less than 8.5 days with 95% confidence. We also place dynamical constraints on additional bodies in the GJ 436 system. Our analysis should serve as a useful guide for similar analyses for which radial velocity measurements are not available, such as those discovered by the Kepler mission. These dynamical constraints on additional planets with periods from 0.5 to 9 days rule out coplanar secular perturbers as small as 10 M_Earth and non-coplanar secular perturbers as small as 1 M_Earth in orbits close in to GJ 436b. We present refined estimates of the system parameters for GJ 436. We also report a sinusoidal modulation in the GJ 436 light curve that we attribute to star spots. [Abridged], Comment: 29 pages, 8 figures, 3 tables, accepted for publication in ApJ

We present the discovery of a new vibrational band system of isotopic CO 2 (carbon dioxide) near 3.3 μm, with multiple strong P, Q and R lines in the prime spectral region used to search for Mars CH 4 (methane). The band system was discovered on Mars using high-resolution spectrometers ( λ / δ λ > 40 , 000 , CSHELL and NIRSPEC) at telescopes (NASA-IRTF and Keck-2) atop Mauna Kea, HI. The observed line intensities and frequencies agree very well with values predicted by a vibrational band model that we developed using known parameters for the molecular levels involved. Using this model, we synthesized spectra for different observing conditions (from Space and ground-based telescopes) and for different spectral resolving powers (5000 to 40 , 000 ). Although the total atmospheric burden on Mars is more than 150 times smaller than on Earth, the greater mixing ratio of CO 2 ensures that its column abundance on Mars is almost 20 times greater than on Earth. Thus, weak telluric CO 2 band systems appear much stronger on Mars. Many molecules of possible biological and geothermal interest have strong signatures at these wavelengths, in particular hydrocarbons owing to their strong ro-vibrational C H stretching modes. For example, the new isotopic CO 2 band-system encompasses lines of CH 4 , C 2 H 6 (ethane), CH 3 OH (methanol) and H 2 O (water). Implications for previous and future searches of biomarker gases are presented.

We describe a technique for analysis of high resolution thermal IR spectra measured with a finite beam (field of view) on the target planetary atmosphere. The model developed allows a beam integrated radiative transfer calculation over the varying line-of-sight velocity, temperature, and species abundance distributed over the field of view, thus recovering information on atmospheric composition, dynamics, and thermal structure. The modeling procedure is comprises four primary aspects: segmentation of the projected observational beam to a grid of beam elements; determining the geometrical properties of the planetary atmospheric region associated with each beam element; calculating the spectrum emergent from the top of the atmosphere of each element; and weighting the ensemble of spectra with the characteristic observational beam response profile and accumulating the contributions. This prescription results in a beam integrated spectrum—a more accurate representation of fully resolved IR rotation–vibration molecular spectra of planetary atmospheres observed with finite aperture telescopes. The method is implemented as a numerical code appropriate for modeling the spectroscopic observations. This paper describes the basic formalism for beam integrated radiation transfer of planetary atmospheres, discusses the salient points of the modeling process, and quantifies limitations. Application of this technique will be illustrated using high resolution atmospheric molecular spectral line measurements of Titan obtained by infrared heterodyne spectroscopy to extract zonal wind field, temperature and C2H6 abundance.

We present new measurements of vibrational band systems of isotopic carbon dioxide (CO2) with multiple strong lines in the wavelength region 3.3–3.7 μm. In our ground-based searches for methane (CH4) and other biomarker gases on Mars, we discovered two new vibrational band systems that we identify as the previously unknown ν2+ν3 band of 16O12C18O and the 2ν1 band of the rare isotope 16O13C18O. We also extended and provide refined spectroscopic constants for the 2ν1 band of 16O12C17O, detecting 38 new lines. The newly discovered 2ν1 band of 16O13C18O at 3.7 μm and the 2ν1 band of 16O12C17O at 3.6 μm extend over the prime spectral region used when searching for deuterated water (HDO) and formaldehyde (H2CO) on Mars. The ν2+ν3 band of 16O12C18O at 3.3 μm interferes with the ν3 band of CH4 at 3.3 μm. If unrecognized, even weak bands of CO2 can obscure searches for trace gases on Mars, so it is important to quantify them. Here, we report molecular parameters from the measured line positions that agree well with values calculated from the known energy levels of these isotopologues, and we provide absolute band strengths for each system.

Ozone is an important observable tracer of martian photochemistry, including odd hydrogen (HOx) species important to the chemistry and stability of the martian atmosphere. Infrared heterodyne spectroscopy with spectral resolution ⩾106⩾106 provides the only ground-based direct access to ozone absorption features in the martian atmosphere. Ozone abundances were measured with the Goddard Infrared Heterodyne Spectrometer and the Heterodyne Instrument for Planetary Wind and Composition at the NASA Infrared Telescope Facility on Mauna Kea, Hawai'i. Retrieved total ozone column abundances from various latitudes and orbital positions (LS=40°LS=40°, 74°, 102°, 115°, 202°, 208°, 291°) are compared to those predicted by the first three-dimensional gas phase photochemical model of the martian atmosphere [Lefevre, F., Lebonnois, S., Montmessin, F., Forget, F., 2004. J. Geophys. Res. 109, doi:10.1029/2004JE002268. E07004]. Observed and modeled ozone abundances show good agreement at all latitudes at perihelion orbital positions (LS=202°LS=202°, 208°, 291°). Observed low-latitude ozone abundances are significantly higher than those predicted by the model at aphelion orbital positions (LS=40°LS=40°, 74°, 115°). Heterogeneous loss of odd hydrogen onto water ice cloud particles would explain the discrepancy, as clouds are observed at low latitudes around aphelion on Mars.

We report 8- to 13-micron spectral observations of Neptune and Uranus from the NASA Infrared Telescope Facility spanning more than a decade. The spectroscopic data indicate a steady increase in Neptune's mean atmospheric 12-micron ethane emission from 1985 to 2003, followed by a slight decrease in 2004. The simplest explanation for the intensity variation is an increase in stratospheric effective temperature from 155 +/- 3 K in 1985 to 176 +/- 3 K in 2003 (an average rate of 1.2 K/year), and subsequent decrease to 165 +/- 3 K in 2004. We also detected variation of the overall spectral structure of the ethane band, specifically an apparent absorption structure in the central portion of the band; this structure arises from coarse spectral sampling coupled with a non-uniform response function within the detector elements. We also report a probable direct detection of ethane emission on Uranus. The deduced peak mole fraction is approximately an order of magnitude higher than previous upper limits for Uranus. The model fit suggests an effective temperature of 114 +/- 3 K for the globally-averaged stratosphere of Uranus, which is consistent with recent measurements indicative of seasonal variation., Accepted for publication in ApJ. 16 pages, 10 figures, 2 tables

Ethane spectral lines were observed in emission from Titan in August 1993, October 1995, and September 1996, at a spectral resolution of λ/Δλ≈10 6 , at wavelength 11.7−11.9 μm using the Goddard Infrared Heterodyne Spectrometer at the NASA Infrared Telescope Facility on Mauna Kea, Hawaii. The ethane mole fraction is determined to be (8.8±2.2)×10 −6 (68.3% confidence limits, “1σ”), averaging the retrievals from each observing run obtained using the “recommended” thermal profile of R. V. Yelle, D. Strobel, E. Lellouch, and D. Gautier (1997, in Huygens: Science, Payload, and Mission (J.-P. Lebreton, Ed.), pp. 243–256, European Space Agency SP-1177).

Infrared emission lines of stratospheric ammonia (NH 3 ) were observed following the collisions of the fragments of Comet Shoemaker–Levy 9 with Jupiter in July of 1994 at the impact sites of fragments G and K. Infrared heterodyne spectra near 10.7 μm were obtained by A. Betz et al. (in Abstracts for Special Sessions on Comet Shoemaker-Levy 9, The 26th Meeting of the Division for Planetary Sciences, Washington DC, 31 Oct.–4 Nov. 1994 , p. 25) using one of the Infrared Spatial Interferometer telescope systems on Mount Wilson. Lineshapes of up to three different NH 3 emission lines were measured at a resolving power of ∼10 7 at multiple times following the impacts. We present here our radiative transfer analysis of the fully resolved spectral lineshapes of the multiple rovibrational lines. This analysis provides information on temperature structure and NH 3 abundance distributions and their temporal changes up to 18 days after impact. These results are compared to photochemical models to determine the role of photochemistry and other mechanisms in the destruction and dilution of NH 3 in the jovian stratosphere after the SL9 impacts. One day following the G impact, the inferred temperature above 0.001 mbar altitude is 283±13 K, consistent with a recent plume splashback model. Cooling of the upper stratosphere to 204 K by the fourth day and to quiescence after a week is consistent with a simple gray atmosphere radiative flux calculation and mixing with cold jovian air. During the first 4 days after impact, NH 3 was present primarily at altitudes above 1 mbar with a column density of (7.7±1.6)×10 17 cm −2 after 1 day and (3.7±0.8)×10 17 cm −2 after 4 days. (Errors represent precision.) We obtained >2.5 times more NH 3 than can be supplied by nitrogen from a large cometary fragment, suggesting a primarily jovian source for the NH 3 . By 18 days postimpact, a return to quiescent upper stratospheric temperature is retrieved for the G region, with an NH 3 column density of 7.3×10 17 cm −2 or more in the lower stratosphere, possibly supplied by NH 3 upwelling across an impact-heated and turbulent tropopause, which may have been masked by initial dust and haze. Above the 1-mbar level, the maximum retrieved column density decreased to 6.5×10 16 cm −2 . Comparison to photochemical models indicates that photolysis alone is not sufficient to account for the loss of NH 3 above 1 mbar by that time, even when chemical reformation of NH 3 is ignored. We speculate that the dispersion of plume material at high altitudes (above 1 mbar) is responsible for the change in the spectra observed a few days postimpact. Data on the K impact region provide qualitatively consistent results.

Infrared heterodyne spectroscopy (λ/Δλ⩾106) enabled the precision measurement of lineshapes of 168 ethylene absorption transitions for 12C2H4 and 88 absorption transitions for 13 C 12 CH 4 . Of the 168 12C2H4 transitions, 96 are assigned to ν7, 17 to ν10, 10 to ν4, and 45 to hotband transitions. The 88 13 C 12 CH 4 transitions have not been assigned. Measurements were made at gas temperatures in the range of 293– 297 K and at pressures in the range of 0.05– 0.5 Torr . Absolute line frequencies and line intensities were retrieved for each of the transitions. Frequencies and absolute intensities of unblended strong lines were determined to better than 5×10 −5 cm −1 and 10%, respectively.

Self- and nitrogen (N2) broadening of ethylene (C2H4) have been measured for the ν 10 20 11,10 ←19 10,9 ethylene transition at 927.01879 cm −1 . The measurements were made using infrared heterodyne spectroscopy with a spectral resolution of ∼1.7×10−4cm−1. At 296 K , the retrieved self-broadening coefficient for the observed transition is 0.1244(92) cm −1 / atm ; the nitrogen-broadening coefficient is 0.0757(99) cm −1 / atm . These results represent the most conservative treatment of experimental and statistical errors. A different purely statistical approach provides consistent values with uncertainties of only a few percent.

We report on the development and testing of the building blocks of a possible compact heterodyne setup in the mid-infrared, which becomes particularly relevant for flight instrumentation. The local oscillator is a Quantum Cascade Laser (QCL) source at 8.6 μm operable at room temperature. The beam combination of the source signal and the local oscillator will occur by means of integrated optics for the 10 μm range, which was characterized in the lab. In addition we investigate the use of superlattice detectors in a heterodyne instrument. This work shows that these different new components can become valuable tools for a compact heterodyne setup.

We report the first direct measurement of wind velocity in the atmosphere of Titan, one of only two examples in our solar system of a slowly-rotating body with a dense atmosphere and a prime target of the Cassini mission. Zonal wind velocity was determined from Doppler shift of ethane lines emitted from Titan's stratosphere (∼0.1–7 mbar) measured by infrared heterodyne spectroscopy near 12 µm (λ/Δ λ ≥ 106). Prograde zonal circulation, in the direction of global rotation, is established with 94% statistical confidence. Results provide information regarding Titan meteorology constraining dynamical theories for slowly-rotating bodies, provide otherwise unobtainable data to optimize the Cassini Huygens Probe investigations, and demonstrate the capability for remotely measuring winds on a small, distant object.

Ethane (C2H6) abundance in Titan's stratosphere is determined from recent ground based high spectral resolution measurements of individual ethane emission line spectra. Lines near 12 μm in the ν9 band of C2H6 were measured at a resolving power of λ/Δλ ∼ 106 with infrared heterodyne spectroscopy at the NASA Infrared Telescope Facility (IRTF). Globally averaged constant-with-height C2H6 mole fractions are retrieved for various possible thermal profiles on Titan. A range of possible stratospheric temperatures is investigated with respect to the data and a corresponding range of acceptable globally averaged ethane mole fractions is retrieved. The data and physical constraints imposed by the observations limit the temperatures in Titan's upper stratosphere to 160–180 K. Corresponding acceptable mole fractions can range from 4 × 10−6 to 1.6 × 10−5 depending on the thermal profile used. For a currently “recommended” thermal profile a mole fraction of 9.4(−4.7, +9.4) × 10−6 is retrieved, some-what lower than previous results, but centrally placed in the acceptable temperature-abundance parameter space.

The EPOXI Discovery Mission of Opportunity reused the Deep Impact flyby spacecraft to obtain spatially and temporally resolved visible photometric and moderate resolution near-infrared (NIR) spectroscopic observations of Earth. These remote observations provide a rigorous validation of whole-disk Earth model simulations used to better understand remotely detectable extrasolar planet characteristics. We have used these data to upgrade, correct, and validate the NASA Astrobiology Institute's Virtual Planetary Laboratory three-dimensional line-by-line, multiple-scattering spectral Earth model. This comprehensive model now includes specular reflectance from the ocean and explicitly includes atmospheric effects such as Rayleigh scattering, gas absorption, and temperature structure. We have used this model to generate spatially and temporally resolved synthetic spectra and images of Earth for the dates of EPOXI observation. Model parameters were varied to yield an optimum fit to the data. We found that a minimum spatial resolution of ∼100 pixels on the visible disk, and four categories of water clouds, which were defined by using observed cloud positions and optical thicknesses, were needed to yield acceptable fits. The validated model provides a simultaneous fit to Earth's lightcurve, absolute brightness, and spectral data, with a root-mean-square (RMS) error of typically less than 3% for the multiwavelength lightcurves and residuals of ∼10% for the absolute brightness throughout the visible and NIR spectral range. We have extended our validation into the mid-infrared by comparing the model to high spectral resolution observations of Earth from the Atmospheric Infrared Sounder, obtaining a fit with residuals of ∼7% and brightness temperature errors of less than 1 K in the atmospheric window. For the purpose of understanding the observable characteristics of the distant Earth at arbitrary viewing geometry and observing cadence, our validated forward model can be used to simulate Earth's time-dependent brightness and spectral properties for wavelengths from the far ultraviolet to the far infrared. Key Words: Astrobiology—Extrasolar terrestrial planets—Habitability—Planetary science—Radiative transfer. Astrobiology 11, 393–408.

We present time series photometry and constraints on additional planets in five of the exoplanetary systems studied by the EPOCh (Extrasolar Planet Observation and Characterization) component of the NASA EPOXI mission: HAT-P-4, TrES-3, TrES-2, WASP-3, and HAT-P-7. We conduct a search of the high-precision time series for photometric transits of additional planets. We find no candidate transits with significance higher than our detection limit. From Monte Carlo tests of the time series using putative periods from 0.5 days to 7 days, we demonstrate the sensitivity to detect Neptune-sized companions around TrES-2, sub-Saturn-sized companions in the HAT-P-4, TrES-3, and WASP-3 systems, and Saturn-sized companions around HAT-P-7. We investigate in particular our sensitivity to additional transits in the dynamically favorable 3:2 and 2:1 exterior resonances with the known exoplanets: if we assume coplanar orbits with the known planets, then companions in these resonances with HAT-P-4b, WASP-3b, and HAT-P-7b would be expected to transit, and we can set lower limits on the radii of companions in these systems. In the nearly grazing exoplanetary systems TrES-3 and TrES-2, additional coplanar planets in these resonances are not expected to transit. However, we place lower limits on the radii of companions that would transit if the orbits were misaligned by 2.0 degrees and 1.4 degrees for TrES-3 and TrES-2, respectively., Comment: 20 pages, 5 figures, accepted for publication in ApJ

The Extrasolar Planet Observation Characterization and the Deep Impact Extended Investigation missions (EPOXI) are currently observing the transits of exoplanets, a comet nucleus at short range, and Earth using the High Resolution Instrument (HRI) - a 0.3 m f/35 telescope - on the Deep Impact flyby spacecraft. The HRI is in a permanently defocused state with the instrument point of focus about 0.6 cm before the focal plane due to the use of a reference flat mirror that became a powered optic due to thermal warping during ground thermal-vacuum testing. Consequently, the point spread function (PSF) covers approximately nine pixels FWHM and is characterized by a patch with three-fold symmetry due to the three-point support structures of the primary and secondary mirrors. The PSF is also strongly color dependent varying in shape and size with change in filtration and target color. While defocus is highly desirable for exoplanet transit observations to limit sensitivity to intra-pixel variation, it is suboptimal for observations of spatially resolved targets. Consequently, all images used in our analysis of such objects were deconvolved with an instrument PSF. The instrument PSF is also being used to optimize transit analysis. We discuss development and usage of an instrument PSF for these observations.

As part of the NASA EPOXI Mission of Opportunity, we observed seven known transiting extrasolar planet systems in order to construct time series photometry of extremely high phase coverage and precision. Here we present the results for four "hot-Jupiter systems" with near-solar stars - HAT-P-4, TrES-3, TrES-2 and WASP-3. We observe ten transits of HAT-P-4, estimating the planet radius Rp = 1.332 \pm 0.052 RJup, the stellar radius R \star = 1.602 \pm 0.061 R \odot, the inclination i = 89.67 \pm 0.30 degrees and the transit duration from first to fourth contact T = 255.6 \pm 1.9 minutes. For TrES-3, we observe seven transits, and find Rp = 1.320 \pm 0.057 RJup, R\star = 0.817 \pm 0.022 R\odot, i = 81.99 \pm 0.30 degrees and T = 81.9 \pm 1.1 minutes. We also note a long term variability in the TrES-3 light curve, which may be due to star spots. We observe nine transits of TrES-2, and find Rp = 1.169 \pm 0.034 RJup, R\star = 0.940 \pm 0.026 R\odot, i = 84.15 \pm 0.16 degrees and T = 107.3 \pm 1.1 minutes. Finally we observe eight transits of WASP-3, finding Rp = 1.385 \pm 0.060 RJup, R\star = 1.354 \pm 0.056 R\odot, i = 84.22 \pm 0.81 degrees and T = 167.3 \pm 1.3 minutes. We present refined orbital periods and times of transit for each target. We state 95% confidence upper limits on the secondary eclipse depths in our broadband visible bandpass centered on 650 nm. These limits are 0.073% for HAT-P-4, 0.062% for TrES-3, 0.16% for TrES-2 and 0.11% for WASP-3. We combine the TrES-3 secondary eclipse information with the existing published data and confirm that the atmosphere likely does not have a temperature inversion., Comment: 34 pages, 21 figures, accepted by ApJ