The JPL Electronic Nose (ENose) is designed as an event or incident monitor to provide rapid, early identification and quantification of changes in the atmosphere caused by leaks or spills of analytes (chemical species) to which it has been trained. With minimal crew interfacing, the autonomous ENose Sensor Unit will monitor the quality of the recycled air in the ISS by continuously sampling air and documenting events where potentially trained-for chemical substances have been released.
The ENose Sensor Unit uses an array of non-specific chemical sensors controlled and analyzed electronically, mimicking the mammalian nose. The pattern of sensor response across the array is recorded; the data are analyzed, and the identity and quantity of the chemical species provoking the response is calculated, using a data analysis program designed for this task. JPL has developed a platform which forms the Sensor Unit of an electronic nose. When the electronic nose is coupled with microprocessors for device control, data acquisition, data analysis and external communication; with power conditioning and with input/output connections for data and power, a fully functional electronic nose is formed. In the laboratory, the Sensor Unit is coupled with a desktop or laptop computer.
The 1st generation ENose Sensor Unit flight experiment, which flew aboard the STS-95 (1998), used an HP-200LX Palmtop Computer for device control and data acquisition; data were collected and analyzed after landing. In the 2nd Generation ENose Sensor Unit, the unit was coupled with a desktop and/or laptop computer for lab experiments. A Personal Data Assistant (PDA), as shown in the photograph, may be used for device control and data collection, with the data analyzed later. The objective of this project is to prepare the ENose Sensor Unit as a technology demonstration on board the International Space Station (ISS). The project will deliver an ENose at the Technology Readiness Level 6 (TRL 6-system/subsystem model or prototype demonstration in a relevant environment, ground or space) for extensive testing and validation in microgravity on the ISS. A modified 2nd Generation ENose Sensor Unit coupled with an Interface Unit will become the 3rd Generation ENose. A number of industrial partners teamed with JPL in the fabrication of the 3rd Generation ENose.
The ENose technology demonstration will run continuously without crew intervention and will be capable of detecting and identifying 10 analytes at concentrations determined by the Health and Environ¬mental Factors Office at Johnson Space Center in Houston, TX. The ENose technology demonstration will be installed on an EXPRESS (EXpedite The PRocessing of Experiments to Space Station) Rack, a standardized payload rack system that transports, stores and supports experiments aboard the ISS, and will conform to requirements for operation.