The miniature time-of-flight mass spectrometer (TOF-MS) is a crucial instrument for detecting water ice in Chinese Lunar Exploration Program, so it is necessary to compare its detection results for pure water vapor and water vapor-binary gas (such as H2O-N2, H2O-CH4, and H2O-Ar) to evaluate its water detection performance. The throughput must be calculated using the measured conductance to test the miniature TOF-MS. According to the V Delta p method, the p Delta t method, whose uncertainty is less than 14.2%, is proposed to measure orifice conductance for water vapor-binary gas, and an apparatus was developed based on those two methods. The orifice conductance of four kinds of pure gases (N2, H2O, CH4, and Ar) was measured using those two methods separately, and the measurement results allowed the conductance of the water vapor-binary gas to be calculated through the Equivalent Single Gas method. The conductance of the water vapor-binary gas was measured using the p Delta t method, and the difference between the calculated and measured results is less than 7%. Hence, the measured conductance allows the miniature TOF-MS to be tested for the water vapor-binary gas. As throughput is from 10-9 to 10-6 Pa m3 s-1, the difference between the test signals of water vapor-binary gas and pure water vapor is less than 40%.

The study of volatiles and the search for water are the primary objectives of the Luna-27 mission, which is planned to land on the south pole of the Moon in 2028. Here we present the tunable Diode Laser Spectrometer (DLS-L) that will be onboard the lander. The DLS-L will perform isotopic analysis of volatiles that are pyrolytically evolved from regolith. This article dives into the design of the spectrometer and the characterisation of isotopic signature retrieval. We look forward to expanding our knowledge of Lunar geochemistry by measuring D/H, 18O/17O/16O, 13C/12C ratios in situ, which would be the one-of-a-kind direct study of the lunar soil isotopy without sample contamination.

Among the essential tools to address global environmental information requirements are the Earth-Observing (EO) satellites with free and open data access. This paper reviews those EO satellites from international space programs that already, or will in the next decade or so, provide essential data of importance to the environmental sciences that describe Earth's status. We summarize factors distinguishing those pioneering satellites placed in space over the past half century, and their links to modern ones, and the changing priorities for spaceborne instruments and platforms. We illustrate the broad sweep of instrument technologies useful for observing different aspects of the physio-biological aspects of the Earth's surface, spanning wavelengths from the UV-A at 380 nanometers to microwave and radar out to 1 m. We provide a background on the technical specifications of each mission and its primary instrument(s), the types of data collected, and examples of applications that illustrate these observations. We provide websites for additional mission details of each instrument, the history or context behind their measurements, and additional details about their instrument design, specifications, and measurements.

Determining the abundance, origin, movement, and storage of water on the Moon with far greater certainty is an ongoing primary goal of lunar exploration. Essential constraints would come from measuring water absorption features repeatedly over the same swaths as a function of time of day from a nearly polar orbit with equatorial periapsis, the goal proposed for BIRCHES (Broadband InfraRed Compact High Resolution Exploration Spectrometer) on the original Lunar Ice Cube mission. Establishing these constraints would be the goal of CLEW, Compact Lunar Explorer for Water, the instrument described in this paper. CLEW has mass, volume, and power requirements comparable but performance, including imaging capability, greatly improved relative to BIRCHES. High heritage CLEW would utilize the NASA GSFC Compact Thermal Imager (CTI), state of the art self-calibrating focal plane array combined with SIDECAR ASIC instrument electronics, combined with an active cooling system and optics similar to CLuHME (Compact Lunar Hydration and Mineralogy Experiment). The platform would likely be significantly more robust and 'roomy', due to availability of high-performance thermal protection components and a larger 12U platform. Planned addition of a compact context camera would enhance image interpretation.

CHandra's Atmospheric Composition Explorer-2 (CHACE-2) is a neutral gas mass spectrometer aboard Chandrayaan-2 orbiter. CHACE-2 is a quadrupole based mass spectrometer which detects neutral atoms/molecules in the mass range of 1-300 amu. The data product from CHACE-2 observations provide the partial pressure for different masses that essentially constitute the mass spectra. CHACE-2 scans different masses using suitable voltages such that each mass is contributed by nine mass bins, known as samples. Each spectrum (mass along x -axis and partial pressure along y-axis) is constructed based on these 9 samples, where the fifth sample is expected to be at the center of the peaks. During the actual measurements in space, mass shifts have been observed such that the center of the peaks doesn't coincide with the expected mass bin, but rather shifted to either lower or higher mass bins. Also, the 9 samples that determines the peak shape need not follow the expected pattern. Suitable criteria have been arrived at in order to verify the quality of each spectrum. In view of the large data sets, an algorithm has been developed to determine and calibrate the mass shift, verify the quality of the spectrum based on the criteria and generate suitable flags in the output file. The algorithm is referred to as 'Peak Filter Algorithm'. The output of the algorithm has been validated and the output has been found to be matching with that expected. The details of the algorithm along with the validation results are presented in this paper. The output of the algorithm is significant for the scientific analysis of CHACE-2 data, and also useful for the analysis of data from instruments similar to that of CHACE-2 in future missions.

The role of atmospheric aerosols in earth's radiative balance is crucial. A thorough knowledge about the spectral optical properties of various types of aerosols is necessary to quantify the net radiative forcing produced by aerosol-light interactions. In this study, we exploited an open-source inverse algorithm based on the Python-PyMieScatt survey iteration method, to retrieve the wavelength dependent Mie-equivalent complex refractive indices of ambient aerosols. This method was verified by obtaining the broadband complex refractive indices of monodisperse polystyrene latex spheres and polydisperse common salt aerosols, using laboratory data collected with a supercontinuum broadband cavity enhanced extinction spectrometer operating in the 420-540 nm wavelength range. Field measurements of ambient aerosol were conducted using a similar cavity enhanced extinction spectrometer (IBBCEES) operating in the wavelength range of 400-550 nm, a multi-wavelength aethalometer, and a scanning mobility particle sizer, in Changzhou city, People's Republic of China. The absorption coefficients for the entire wavelength range were retrieved using the absorption Angstrom exponents calculated from a pair of measured absorption coefficients at known wavelengths. The survey iteration method takes scattering and absorption coefficients, wavelength, and size distributions as inputs; and it calculates the Mie-equivalent wavelength dependent complex refractive index (RI = n +/- ik) and estimated errors. The retrieved field RI values ranged from 1.66 <= n <= 1.80 to 1.65 <= n <= 1.86 and from 0.036 <= k <= 0.038 to 0.062 <= k <= 0.067 in the wavelength range (400-550 nm), for low and high aerosol loading conditions, respectively. Additionally, we derived the spectral dependencies of scattering and absorption coefficients along with the n and k Angstrom exponents (AE). The nAE and kAE estimated values suggest a stronger wavelength dependence for aerosol light scattering compared to absorption, and a decreasing trend for the spectrally dependent single scattering albedo during both loading conditions. The extremum of errors in the retrieved n and k values were quantified by considering (a) uncertainties in input parameters in the broad spectral region (400-550 nm), (b) using CAPS extinction values at 530 nm and (c) an estimated size distribution incorporating the coarse particles (at 530 nm).

The High-resolution Volatiles and Minerals Moon Mapper (HVM3) is a pushbroom shortwave infrared (SWIR) imaging spectrometer developed at NASA's Jet Propulsion Laboratory (JPL), California Institute of Technology, for the Lunar Trailblazer mission. The mission, a part of NASA's Small Innovative Missions for Planetary Exploration (SIMPLEx) program, pairs HVM3 with University of Oxford's Lunar Thermal Mapper (LTM) to determine the form, abundance, and distribution of water on the Moon, while providing a potential reconnaissance opportunity for future landed missions. The HVM3 optical design utilizes heritage from NASA's Moon Mineralogy Mapper (M-3), and maintains a compact form while extending to longer wavelengths. Operating at F/3.4 with a spatial resolution of 70 meters per pixel and a spectral resolution of 10 nm over the 0.6 to 3.6 microns spectral range, HVM3 is optimized for the detection of volatiles to map OH, bound H2O, and water ice at the Moon, including the Moon's permanently shadowed regions (PSRs). We discuss the optical specifications, optical design, alignment, and initial measured laboratory performance of the HVM3 instrument.

Planetary volatiles refer to material components that can be separated from a solid sample as a gas phase via physical processes such as impact and heating. On the one hand, these materials are crucial for studying the formation of the solar system and the evolution of planets and their satellites. On the other hand, they provide resources for deep space exploration. Along with the exploration of deep space in recent decades, the detection of volatiles has also advanced our understanding of the cosmos. For example, the discovery of the Moon's polar ice has changed the impression that the Moon seriously lacks volatiles, the discovery of suspected biogenic methane on Mars has rekindled people's hope that Mars may once have harbored life, and studies of the hydrogen isotopes in comet 67P have suggested that most of the water on Earth had come from asteroids instead of comets. The combination of pyrolysis in a high-temperature furnace with mass spectrometry is the main method used to extract and analyze volatiles from deep space. This paper summarizes the extraction methods used and the functional parameters of volatile extraction payloads in deep space exploration and compares the performance indexes of the mass spectrometers used for volatile analysis. Furthermore, this paper introduces some volatiles payloads that may be extracted and analyzed in future deep space exploration missions.

The PLanetary extreme Ultraviolet Spectrometer (PLUS) is a project funded by the Italian Space Agency focused on the development of an extreme (EUV) and far-ultraviolet (FUV) high-performance spectrograph, which adopts a dual channel optical scheme. Thanks to an optimized layout based on the use of Variable Line Space (VLS) gratings in an off-Rowland configuration, high spectral and spatial resolution are achieved. The efficiency improvement is obtained by the optimization of the coatings on the optical components. Improved detection limit, shorter observations integration time and unprecedented performance in terms of dynamic range will be achieved by the use of high resolution/dynamic range solar blind photon counting detectors. The photon counting detectors will be based on a Micro-Channel Plate (MCP) coupled with an Application Specific Integrated Circuit (ASIC) read out system.

The JUICE (JUpiter ICy moons Explorer) mission by ESA aims to explore the emergence of habitable worlds around gas giants and the Jupiter system as an archetype of gas giants. MAJIS (Moons and Jupiter Imaging Spectrometer) is the visible to near-infrared imaging spectrometer onboard JUICE which will characterize the surfaces and exospheres of the icy moons and perform monitoring of the Jupiter atmosphere. The launch is scheduled for 2023 with the first MAJIS observations inside the Jovian system occurring more than 8 years later. The MAJIS optical head is equipped with two Teledyne H1RG detectors, one for each of the two spectrometer channels (VIS-NIR and IR). This paper describes the characterization of the VIS-NIR Focal Plane Unit. These detectors will be operated in a non-standard way, allowing near/full-frame retrieval over short integration times (<< 1 sec) while maintaining good noise performance. After a quick description of the characterization strategy that was designed to evaluate the performances of the VIS-NIR detector according to the MAJIS operational specifications, the paper will address the data analyses and the main results of the characterization campaign. The major performance parameters such as dark current, linearity, noise, quantum efficiency, and operability will be presented and compared with the requirements.