An optimized three-dimensional linear-electric-field time-of-flight analyzer

A Systematic Review of Product Design for Space Instrument Innovation, Reliability, and Manufacturing

The design and development of space instruments are considered to be distinct from that of other products. It is because the key considerations are vastly different from those that govern the use of products on planet earth. The service life of a space instrument, its use in extreme space environments, size, weight, cost, and the complexity of maintenance must all be considered. As a result, more innovative ideas and resource support are required to assist mankind in space exploration. This article reviews the impact of product design and innovation on the development of space instruments. Using a systematic literature search review and classification, we have identified over 129 papers and finally selected 48 major articles dealing with space instrument product innovation design. According to the studies, it is revealed that product design and functional performance is the main research focuses on the studied articles. The studies also highlighted various factors that affect space instrument manufacturing or fabrication, and that innovativeness is also the key in the design of space instruments. Lastly, the product design is important to affect the reliability of the space instrument. This review study provides important information and key considerations for the development of smart manufacturing technologies for space instruments in the future.

Invited article: Characterization of background sources in space-based time-of-flight mass spectrometers

For instruments that use time-of-flight techniques to measure space plasma, there are common sources of background signals that evidence themselves in the data. The background from these sources may increase the complexity of data analysis and reduce the signal-to-noise response of the instrument, thereby diminishing the science value or usefulness of the data. This paper reviews several sources of background commonly found in time-of-flight mass spectrometers and illustrates their effect in actual data using examples from ACE-SWICS and MESSENGER-FIPS. Sources include penetrating particles and radiation, UV photons, energy straggling and angular scattering, electron stimulated desorption of ions, ion-induced electron emission, accidental coincidence events, and noise signatures from instrument electronics. Data signatures of these sources are shown, as well as mitigation strategies and design considerations for future instruments.

A time digitizer for space instrumentation using a field programmable gate array

Space instruments such as time-of-flight (TOF) mass spectrometers and altimeters rely on time-to-digital converters (TDCs) to measure accurately times in the picosecond to microsecond range. Time-to-digital conversion is often implemented with analog circuitry or more recently with custom ASIC (Application Specific Integrated Circuit) devices. The analog approach may be costly in terms of circuit board area and parts count, while ASIC development is risky and costly when system requirements may change. Here, we present a highly flexible, accurate, and low-cost field-programmable gate array (FPGA) implementation of such TDC functionality. Compared with other technologies, this method reduces the parts count in TOF-supporting circuits and provides design flexibility in TOF instrumentation, especially for use in space or for applications with a number of sensors too small to warrant the development of a dedicated ASIC. Our technique can accommodate one or more STOP pulse measurements for each START pulse as signal reference, effectively providing measurements of multiple times-of-flight with the same start trigger. Alternatively, all pulse event edges can receive an absolute time stamp, enabling a broad set of new sensor applications. This novel design is based on the construction of a delay-line internal to the FPGA. Propagation variations due to temperature and supply voltage, which typically limit FPGA-based timing designs, are automatically compensated, allowing active signal processing 100% of the time. A methodology for the characterization of internal delay-line timing and nonlinearity has also been developed and is not specific to a particular FPGA architecture. We describe the design of this FPGA-based TDC and also describe detailed tests with a Xilinx XC2V1000. For single non-repetitive events, this design achieves 60 ps accuracy (standard deviation of error); a simplified implementation is suitable for non-reprogrammable FPGAs.