Hand-Held Devices Detect Explosives and Chemical Agents
- Friday, 01 January 2010
Smaller, with enhanced capabilities. Less expensive, while providing improved performance. Energy efficient, without sacrificing capabilities. Smaller, less expensive, and energy efficient—but still highly durable under some of the most extreme conditions known.
Contradictions like these are commonplace when designing sensor instruments for spacecraft. The Curiosity Mars Science Laboratory, for example, is set to launch in 2011 with an anticipated 10 instruments onboard that must endure the launch, an 8-month journey to Mars, landing, and the unfriendly environment of the Red Planet. Packing that much scientific punch into a single, reliable, one-shot package requires the most advanced technology available.
Given the high cost of development and launch; the need for consistent, high-level operation in harsh conditions and without the possibility of maintenance; and the limited real estate available on a spacecraft; NASA continually seeks ways both to develop new sensor technology and to advance existing devices to meet the demands of space exploration—in many cases through collaboration with private industry. Sometimes, the effort results in smaller, less expensive, more energy efficient, and highly durable products for use on Earth, as well.
NASA’s Astrobiology Science and Technology Instrument Development (ASTID) program encourages the development of innovative instruments equally capable of fulfilling astrobiology science requirements on space missions or related science objectives on Earth. Through ASTID and the Small Business Innovation Research (SBIR) program, Ion Applications Inc., of West Palm Beach, Florida, worked to meet NASA’s need for a miniature version of a powerful sensor technology known as an ion mobility spectrometer (IMS).
Ion mobility spectrometry is a fast, highly sensitive method for separating and identifying gaseous molecules. In an IMS device, ionized molecules sampled from the air travel through a drift tube containing a buffer gas. The speed of travel is influenced by the ion’s mass, size, shape, and charge. By measuring how quickly the ions migrate through the tube, IMS can identify a significant variety of molecules with part-per-billion sensitivity. The instrument displays lesser sensitivity toward other molecules, such as light hydrocarbons and noble gasses, under normal operating conditions.
“An IMS can basically detect almost anything, from heavyweight compounds all the way down to permanent gasses like hydrogen,” says Alex Lowe, Ion Applications’ vice president of sales and marketing. This capability makes IMS an obviously valuable detection instrument; in particular, it has been the technology of choice for explosives and chemical warfare agent detection since the 1960s and is in widespread use for airport security and military applications.
NASA had already developed a gas chromatograph ion mobility spectrometer (GC-IMS) called the mini-Cometary Ice and Dust Experiment (miniCIDEX). The device combines gas chromatography with ion mobility spectrometry to provide highly sensitive gas analysis for astrobiology missions. While the GC device had been successfully miniaturized, the IMS component needed to be smaller and capable of producing accurate readings with a reduced sample size. With SBIR support from Ames Research Center, Ion Applications developed a unique, miniature, Kovar (an alloy) and ceramic IMS cell; simplified electronics; and software for control and spectra acquisition.
The resulting Mini-Cell IMS proved to be a more sensitive, reliable, and rugged tool than existing IMS technology. For NASA, the improved IMS device could be used for future missions to planets, moons, and comets, or as a space-saving tool to monitor air quality on the International Space Station. On Earth, the applications are proving even more varied and beneficial.