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%.

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.

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 high-spatial-resolution distributions of the mass concentration and chemical composition of submicron particulate matter (PM1) across four different functional districts in Lanzhou, a typical northwestern city in China, were studied during the winter haze pollution period using an on-road real-time mobile monitoring system. The purpose of this study is to characterize the spatial variation in the sources and chemical formation of aerosols at the intra-urban scale. A higher PM1 mass concentration (63.0 mu g m(-3)) was observed in an industrially influenced district (XG) with major contributions (70.4%) from three secondary inorganic species (sulfate, nitrate, and ammonium) and two oxygenated organic aerosol (OOA) components with different oxygenation levels. Compared with the densely populated district (CG), sulfate and more-oxidized OOA were the two most distinct contributors to the elevated PM1 mass in XG during the daytime (30.9% in XG vs. 17.5% in CG), whereas nitrate and less-oxidized OOA dominated (41.4% in XG vs. 30.6% in CG) during the nighttime. A lower PM1 mass (44.3 mu g m(-3)) was observed in CG and was contributed predominantly by primary organic aerosols emitted from traffic, cooking, and heating activities. The chemical formation mechanisms of secondary PM1 species in the two different districts during the daytime and nighttime are further examined, which indicated the important photochemical formations of nitrate in CG but sulfate in XG during the day-time, whereas favorable aqueous-phase formations of nitrate and LO-OOA in both districts during the nighttime. The stronger atmospheric oxidation capability might be a key factor leading to the more significant formations of secondary species in XG than CG. These results illustrate city-scale aerosol loading and chemical processes and are useful for local policy makers to develop differentiated and efficient mitigation strategies for the improvement of air quality in Lanzhou.

The CHandra's Atmospheric Composition Explorer-2 (CHACE-2) experiment aboard Chandrayaan-2 orbiter will study in situ, the composition of the lunar neutral exosphere in the mass range 1-300 amu with mass resolution of 0.5 amu. It will address the spatial and temporal variations of the lunar exosphere, and examine water vapour as well as heavier species in it. In this article, results of the major characterization and calibration experiments of CHACE-2 are presented, with an outline of the qualification tests for both the payload and ground segment.

In-Situ Resource Utilization (ISRU) is a key NASA initiative to exploit resources at the site of planetary exploration for mission-critical consumables, propellants, and other supplies. The Resource Prospector mission, part of ISRU, is scheduled to launch in 2020 and will include a rover and lander hosting the Regolith & Environment Science and Oxygen & Lunar Volatile Extraction (RESOLVE) payload for extracting and analyzing lunar resources, particularly low molecular weight volatiles for fuel, air, and water. RESOLVE contains the Lunar Advanced Volatile Analysis (LAVA) subsystem with a Gas Chromatograph-Mass Spectrometer (GC-MS). RESOLVE subsystems, including the RP'15 rover and LAVA, are in NASA's Engineering Test Unit (ETU) phase to assure that all vital components of the payload are space-flight rated and will perform as expected during the mission. Integration and testing of LAVA mass spectrometry verified reproducibility and accuracy of the candidate MS for detecting nitrogen, oxygen, and carbon dioxide. The RP'15 testing comprised volatile analysis of water-doped simulant regolith to enhance integration of the RESOLVE payload with the rover. Multiple tests show the efficacy of the GC to detect 2% and 5% water-doped samples.

Radiative forcing by aerosol particles containing black carbon (BC) may be positive or negative depending on specific atmospheric conditions. Black carbon itself absorbs solar radiation and thereby heats the surrounding environment. On the other hand, as a result of atmospheric aging, BC-containing particles may become hydrophilic due to oxidation, condensation, and/or coagulation of water-soluble material. The aged particles can act as cloud condensation nuclei (CCN) and contribute to cloud formation that may result either in cooling or heating. In this work, through a series of laboratory experiments, we investigate the transformation of soot particles from hydrophobic to hydrophilic and estimate the atmospheric residence time required for this transformation. Ethylene flame-generated soot particles were size-selected and exposed to OH radicals in a Potential Aerosol Mass flow reactor. Aging was simulated via OH exposures equivalent to atmospheric lifetimes over a range from hours to multiple days. The chemical composition of the organic coatings as a function of OH exposure was monitored with an Aerodyne Aerosol Mass Spectrometer. The CCN activity of the aged soot particles was measured as a function of OH exposure and chemical composition. Experimental measurements indicate that heterogeneous OH oxidation of initially CCN-inactive nascent soot produces CCN-active particles. Critical supersaturations at integrated OH exposures equivalent to 0.4, 2, and 10 days are 2.1%, 0.82%, and 0.40%. Corresponding values for the effective hygroscopicity parameter, K-eff,, ranged from K-eff < 8 x 10(-4) to K-eff = 0.09 as a function of OH exposure. Condensation of hydrophilic organic or inorganic coatings (produced from oxidation of gas-phase precursors introduced to the flow reactor) on soot particles speeds up the CCN activation by a factor of 6-50 depending on the nature and thickness of the coating. The results suggest that CCN activation of atmospheric BC-containing particles is primarily due to secondary coatings. (C) 2014 Elsevier Ltd. All rights reserved.

The Lunar Volatile Resources Analysis Package (L-VRAP) has been conceived to deliver some of the objectives of the proposed Lunar Lander mission currently being studied by the European Space Agency. The purpose of the mission is to demonstrate and develop capability; the impetus is very much driven by a desire to lay the foundations for future human exploration of the Moon. Thus, L-VRAP has design goals that consider lunar volatiles from the perspective of both their innate scientific interest and also their potential for in situ utilisation as a resource. The device is a dual mass spectrometer system and is capable of meeting the requirements of the mission with respect to detection, quantification and characterisation of volatiles. Through the use of appropriate sampling techniques, volatiles from either the regolith or atmosphere (exosphere) can be analysed. Furthermore, since L-VRAP has the capacity to determine isotopic compositions, it should be possible for the instrument to determine the sources of the volatiles that are found on the Moon (be they lunar per se, extra-lunar, or contaminants imparted by the mission itself). (C) 2012 Elsevier Ltd. All rights reserved.

We present the Volatile Analysis by Pyrolysis of Regolith (VAPoR) instrument design and demonstrate the validity of an in situ pyrolysis mass spectrometer for evolved gas analyses of lunar and planetary regolith samples. In situ evolved gas analyses of the lunar regolith have not yet been carried out and no atmospheric or evolved gas measurements have been made at the lunar poles. VAPoR is designed to do both kinds of measurements, is currently under development at NASA's Goddard Space Flight Center, and will be able to heat powdered regolith samples or rock drill fines up to 1400 degrees C in vacuo. To validate the instrument concept, evolved gas species released from different planetary analogs were determined as a function of temperature using a laboratory breadboard. Evolved gas measurements of an Apollo 16 regolith sample and a fragment of the carbonaceous meteorite Murchison were made by VAPoR and our results compared with existing data. The results imply that in situ evolved gas measurements of the lunar regolith at the polar regions by VAPoR will be a very powerful tool for identifying water and other volatile signatures of lunar or exogenous origin as potential resources for future human exploration. (C) 2010 Elsevier Ltd. All rights reserved.