Performance evaluation of a miniature magnetic sector mass spectrometer onboard a satellite in space.

With the rapid development of space technology in China, it is urgent to use mass spectrometer to detect the space environment. In this work, a space miniature magnetic sector mass spectrometer is evaluated, which consists of three subsystems: (1) physical unit, (2) electric control unit, (3) and high voltage power. It has 90° magnetic sector-field analyzer with double trajectory, in which a trajectory measurement range is from 1 to 12 amu, the other range is from 6 to 90 amu.The mass spectrometer has two work models, one is used to measure space neutral gas when the filament of mass spectrometer ion source turned on, the other is used to measure space charged ions when the filament turned off. The absolute resolution of this device is less than 1 amu, the minimum detectable ion current is about 10-13 A, and the sensitivity is 10-6 A/Pa (N2). Its overall size is 170 mm × 165 mm × 170 mm, its weight is 4.5 kg, and its power consumption is 18 W. A series of environmental adaptability tests, including high and low temperature cycle, shock, vibration, thermal vacuum cycle, were carried out on the ground before launching, and sensitivity and peak position were also calibrated on the ground. In November 2012, the mass spectrometer was carried by an experimental satellite to 499 km sun synchronization and is still working right now. It successfully detected the atmosphere compositions both in the satellite orbit and gas-emitted from satellite, including O, He, 12CO2, 13CO2, H2, N2, O2, H2O, and so on.

Design of a Compact Time-of-Flight Mass Spectrometer for Space Application.

A miniature reflectron time-of-flight mass spectrometer (TOF MS) with orthogonal extraction coupled with electron impact (EI) ionization source can be used to perform in situ gas composition analysis in a planetary environment. However, performances such as the mass resolution, sensitivity, limit of detection, mass range, and mass accuracy are often decreased because of miniaturization. Herein, a compact instrument for space applications has been developed, and its performance has been evaluated. The mass of the TOF MS is 13.4 kg, with dimensions of 300 mm × 200 mm × 200 mm, and the power consumption is 25 W. In this paper, the design of the ion source, mass analyzer, and detector is discussed in detail. The upper limit of the mass range is greater than 500 amu, and the best resolving power obtained so far on the miniature TOF MS is around 405 at full width half maximum (FWHM); other performance indexes of the instrument are also determined, where the worst case for mass stability is 0.49%, together with a mass accuracy of 0.12% and a sensitivity of 0.6 mV/ppm.