Mass Spectrometers in Space!

Exploration of our solar system over several decades has benefitted greatly from the sensitive chemical analyses offered by spaceflight mass spectrometers. When dealing with an unknown environment, the broadband detection capabilities of mass analyzers have proven extremely valuable in determining the composition and thereby the basic nature of space environments, including the outer reaches of Earth s atmosphere, interplanetary space, the Moon, and the planets and their satellites. Numerous mass analyzer types, including quadrupole, monopole, sector, ion trap, and time-of-flight have been incorporated in flight instruments and delivered robotically to a variety of planetary environments. All such instruments went through a rigorous process of application-specific development, often including significant miniaturization, testing, and qualification for the space environment. Upcoming missions to Mars and opportunities for missions to Venus, Europa, Saturn, Titan, asteroids, and comets provide new challenges for flight mass spectrometers that push to state of the art in fundamental analytical technique. The Sample Analysis at Mars (SAM) investigation on the recently-launch Mars Science Laboratory (MSL) rover mission incorporates a quadrupole analyzer to support direct evolved gas as well as gas chromatograph-based analysis of martian rocks and atmosphere, seeking signs of a past or present habitable environment. A next-generation linear ion trap mass spectrometer, using both electron impact and laser ionization, is being incorporated into the Mars Organic Molecule Analyzer (MOMA) instrument, which will be flown to Mars in 2018. These and other mass spectrometers and mission concepts at various stages of development will be described

Tandem Mass Spectrometry on a Miniaturized Laser Desorption Time-of-Flight Mass Spectrometer

Tandem mass spectrometry (MSMS) is a powerful and widely-used technique for identifying the molecular structure of organic constituents of a complex sample. Application of MSMS to the study of unknown planetary samples on a remote space mission would contribute to our understanding of the origin, evolution, and distribution of extraterrestrial organics in our solar system. Here we report on the realization of MSMS on a miniaturized laser desorption time-of-flight mass spectrometer (LD-TOF-MS), which is one of the most promising instrument types for future planetary missions. This achievement relies on two critical components: a curved-field reflectron and a pulsed-pin ion gate. These enable use of the complementary post-source decay (PSD) and laser-assisted collision induced dissociation (L-CID) MSMS methods on diverse measurement targets with only modest investment in instrument resources such as volume and weight. MSMS spectra of selected molecular targets in various organic standards exhibit excellent agreement when compared with results from a commercial, laboratory-scale TOF instrument, demonstrating the potential of this powerful technique in space and planetary environments

Probing the Composition of Primitive Solar System Materials with a Compact Laser Mass Spectrometer

To contribute to and complement our understanding of the processes governing the formation,distribution, and evolution of primitive materials throughout the solar system, it will be critical toform connections between broad remote sensing spectroscopic surveys, laboratorymeasurements of analogs and samples delivered to Earth, and in situ measurements of thesurface composition on future primitive body missions. Recently, a laboratory prototypeemploying resonance two-step laser mass spectrometry [Getty et al., 2012] has been coupledto a cryogenic sample stage to enable measurements of analog samples that are relevant tothese fundamental questions. Analyses of mineral-aromatic mixtures and meteorite powderswill be presented. Our goals are twofold: (1) to conduct laboratory studies on solar systemanalog, meteoritic, and potentially returned samples to elucidate composition, and (2) toprovide a compact but capable analytical instrument for discovery-driven in situ interrogationof surface chemistry on a future mission, such as to a Trojan asteroid, comet, or icy moon

Characterization of a Carbon Nanotube Field Emission Electron Gun for the VAPoR Miniaturized Pyrolysis-Time-of-Flight Mass Spectrometer

We are developing the VAPoR (Volatile Analysis by Pyrolysis of Regolith) instrument towards studying soil composition, volatiles, and trapped noble gases in the polar regions of the Moon. VAPOR will ingest a soil sample and conduct analysis by pyrolysis and time-of-flight mass spectrometry (ToF-MS). Here, we describe miniaturization efforts within this development, including a carbon nanotube (CNT) field emission electron gun that is under consideration for use as the electron impact ionization source for the ToF-MS

Development of a Low Power Gas Chromatograph-Mass Spectrometer for In-Situ Detection of Organics in Martian Soil

The Mars Organic Molecule Analyzer (MOMA) is a joint venture by NASA and the European Space Agency (ESA) to develop a sensitive, light-weight, low-power mass spectrometer for chemical analysis on Mars. MOMA is a key analytical instrument aboard the 2018 ExoMars rover mission seeking signs of past or present life. The current prototype was built to demonstrate operation of gas chromatography (OC) and laser desorption (LD) mass spectrometry under martian ambient conditions (5-7 Torr of CO2-rich atmosphere). Recent reports have discussed the MO MA concept, design and performance. Here, we update the current prototype performance, focusing specifically on the GCMS mode

Two-step Laser Time-of-Flight Mass Spectrometry to Elucidate Organic Diversity in Planetary Surface Materials.

Laser desorption/ionization time-of-flight mass spectrometry (LD-TOF-MS) holds promise to be a low-mass, compact in situ analytical capability for future landed missions to planetary surfaces. The ability to analyze a solid sample for both mineralogical and preserved organic content with laser ionization could be compelling as part of a scientific mission pay-load that must be prepared for unanticipated discoveries. Targeted missions for this instrument capability include Mars, Europa, Enceladus, and small icy bodies, such as asteroids and comets

Evaluation of Pulse Counting for the Mars Organic Mass Analyzer (MOMA) Ion Trap Detection Scheme

The Mars Organic Mass Analyzer is being developed at Goddard Space Flight Center to identify organics and possible biological compounds on Mars. In the process of characterizing mass spectrometer size, weight, and power consumption, the use of pulse counting was considered for ion detection. Pulse counting has advantages over analog-mode amplification of the electron multiplier signal. Some advantages are reduced size of electronic components, low power consumption, ability to remotely characterize detector performance, and avoidance of analog circuit noise. The use of pulse counting as a detection method with ion trap instruments is relatively rare. However, with the recent development of high performance electrical components, this detection method is quite suitable and can demonstrate significant advantages over analog methods. Methods A prototype quadrupole ion trap mass spectrometer with an internal electron ionization source was used as a test setup to develop and evaluate the pulse-counting method. The anode signal from the electron multiplier was preamplified. The an1plified signal was fed into a fast comparator for pulse-level discrimination. The output of the comparator was fed directly into a Xilinx FPGA development board. Verilog HDL software was written to bin the counts at user-selectable intervals. This system was able to count pulses at rates in the GHz range. The stored ion count nun1ber per bin was transferred to custom ion trap control software. Pulse-counting mass spectra were compared with mass spectra obtained using the standard analog-mode ion detection. Prelin1inary Data Preliminary mass spectra have been obtained for both analog mode and pulse-counting mode under several sets of instrument operating conditions. Comparison of the spectra revealed better peak shapes for pulse-counting mode. Noise levels are as good as, or better than, analog-mode detection noise levels. To artificially force ion pile-up conditions, the ion trap was overfilled and ions were ejected at very high scan rates. Pile-up of ions was not significant for the ion trap under investigation even though the ions are ejected in so-called 'ion-micro packets'. It was found that pulse counting mode had higher dynamic range than analog mode, and that the first amplification stage in analog mode can distort mass peaks. The inherent speed of the pulse counting method also proved to be beneficial to ion trap operation and ion ejection characterization. Very high scan rates were possible with pulse counting since the digital circuitry response time is so much smaller than with the analog method. Careful investigation of the pulse-counting data also allowed observation of the applied resonant ejection frequency during mass analysis. Ejection of ion micro packets could be clearly observed in the binned data. A second oscillation frequency, much lower than the secular frequency, was also observed. Such an effect was earlier attributed to the oscillation of the total plasma cloud in the ion trap. While the components used to implement pulse counting are quite advanced, due to their prevalence in consumer electronics, the cost of this detection system is no more than that of an analog mode system. Total pulse-counting detection system electronics cost is under $25

In Situ Detection of Organic Molecules on the Martian Surface With the Mars Organic Molecule Analyzer (MOMA) on Exomars 2018

The Mars Organic Molecule Analyzer (MOMA) investigation on the 2018 ExoMars rover will examine the chemical composition of samples acquired from depths of up to two meters below the martian surface, where organics may be protected from radiative and oxidative degradation. The MOMA instrument is centered around a miniaturized linear ion trap (LIT) that facilitates two modes of operation: i) pyrolysisgas chromatography mass spectrometry (pyrGC-MS); and, ii) laser desorptionionization mass spectrometry (LDI-MS) at ambient Mars pressures. The LIT also enables the structural characterization of complex molecules via complementary analytical capabilities, such as multi-frequency waveforms (i.e., SWIFT) and tandem mass spectrometry (MSMS). When combined with the complement of instruments in the rovers Pasteur Payload, MOMA has the potential to reveal the presence of a wide range of organics preserved in a variety of mineralogical environments, and to begin to understand the structural character and potential origin of those compounds

Excess of L-Alanine in Amino Acids Synthesized in a Plasma Torch Generated by a Hypervelocity Meteorite Impact Reproduced in the Laboratory

We present a laboratory reproduction of hypervelocity impacts of a carbon containing meteorite on a mineral substance representative of planetary surfaces. The physical conditions of the resulting impact plasma torch provide favorable conditions for abiogenic synthesis of protein amino acids: We identified glycine and alanine, and in smaller quantities serine, in the produced material. Moreover, we observe breaking of alanine mirror symmetry with L excess, which coincides with the bioorganic world. Therefore the selection of L-amino acids for the formation of proteins for living matter could have been the result from plasma processes occurring during the impact meteorites on the surface. This indicates that the plasma torch from meteorite impacts could play an important role in the formation of biomolecular homochirality. Thus, meteorite impacts possibly were the initial stage of this process and promoted conditions for the emergence of a living matter