Shannon P. Jackson

Sensor Web for in situ exploration of gaseous biosignatures

A Sensor Web is a system of intra-communicating spatially distributed sensor pods that can be deployed to monitor and explore new environments. By its very nature, the Sensor Web provides spatio-temporal data in a form consistent with that needed for environment modeling and represents a new paradigm for in situ monitoring and exploration. For example, a wireless web of scattered sensor pods on the Martian surface is an ideal way to pursue gaseous biosignature searches. Sensor Web climate and agricultural monitoring on Earth (particularly when coupled with remote measurements) characterize significant commercial opportunities for this technology. Recent laboratory demonstrations at the Jet Propulsion Laboratory (JPL) have shown the potential of current Sensor Web technology, These demonstrations are leading to a JPL effort to field a Sensor Web in Baja California to examine gaseous biosignatures from the microbial mats there.

Operation of an Electronic Nose Aboard the Space Shuttle and Directions for Research for a Second Generation Device

A flight experiment to test the operation of an Electronic Nose developed and built at JPL and Caltech was done aboard STS-95 in October-November, 1998. This ENose uses conductometric sensors made of insulating polymer-carbon composite films; it has a volume of 1.7 liters, weighs 1.4 kg including the operating computer and operates on 1.5 W average power. In the flight experiment, the ENose was operated continuously for 6 days and recorded the sensors’ response to changes in air in the mid-deck of the orbiter. The ENose had been trained to identify and quantify ten common contaminants at the 24-hour Spacecraft Maximum Allowable Concentration (SMAC) level. Most SMACs are on the order of 10-100 ppm. The experiment was controlled by collecting air samples daily and analyzing them using standard analytical techniques after the flight. The device is microgravity insensitive.

Monitoring Space Shuttle Air for Selected Contaminants Using an Electronic Nose

A miniaturized electronic nose has been constructed at JPL in collaboration with Caltech. This array of conductometric sensors has been trained to detect and quantify the presence of vapors in the air; the compounds detected have been found as contaminants in shuttle air. This device has potential application as a miniature, distributed device for monitoring and controlling the constituents in air.

Development of sample verification system for sample return missions

This paper describes the development of a proof-of-concept sample verification system (SVS) for in-situ mass measurement of planetary rock and soil sample in future robotic sample return missions. Our proof-of-concept SVS device contains a 10 cm diameter pressure sensitive elastic membrane placed at the bottom of a sample canister. The membrane deforms under the weight of accumulating planetary sample. The membrane is positioned in proximity to an opposing substrate with a narrow gap. The deformation of the membrane makes the gap to be narrower, resulting in increased capacitance between the two nearly parallel plates. Capacitance readout circuitry on a nearby printed circuit board (PCB) transmits data via a low-voltage differential signaling (LVDS) interface. The fabricated SVS proof-of-concept device has successfully demonstrated approximately 1pF/gram capacitance change.1, 2