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The current status of III-V semiconductor diode lasers emitting between 1 -5 μm wavelengths to be used as light sources for absorption spectroscopy is reviewed. The emission wavelength of the laser is chosen to coincide with the primary absorption line of a molecule or one of its many overtones. The lasers, with a single longitudinal mode emission, are wavelength tuned over several angstroms by modulating the drive current of the device. This sweeping of the wavelength leads to the nomenclature tunable diode laser or TDL. Single mode distributed feedback (DFB) strained layer InGaAs(P) lasers grown on InP substrates with emission wavelengths from 1.2 to 2.06 μm have been developed at JPL, and several devices will be used for planetary atmospheric studies for the first time.

ChemCam is one of the 10 instrument suites on the Mars Science Laboratory, a martian rover being built by Jet Propulsion Laboratory, for the next NASA mission to Mars (MSL 2009). ChemCam is an instrument package consisting of two remote sensing instruments: a Laser-Induced Breakdown Spectrometer (LIBS) and a Remote Micro-Imager (RMI). LIBS provides elemental compositions of rocks and soils, while the RMI places the LIBS analyses in their geomorphologic context. Both instruments rely on an autofocus capability to precisely focus on the chosen target, located at distances from the rover comprised between 1 and 9 m for LIBS, and 2 m and infinity for RMI. ChemCam will help determine which samples, within the vicinity of the MSL rover, are of sufficient interest to use the contact and in-situ instruments for further characterization.

A microhygrometer has been developed at JPL's Microdevices Laboratory based on the principle of dewpoint/frostpoint detection. The surface acoustic wave device used in this instrument is approximately two orders of magnitude more sensitive to condensation than the optical sensor used in chilled-mirror hygrometers. In tests in the laboratory and on the NASA DC8, the SAW hygrometer has demonstrated more than an order of magnitude faster response than commercial chilled-mirror hygrometers, while showing comparable accuracy under steady-state conditions. Current development efforts are directed toward miniaturization and optimization of the microhygrometer electronics for flight validation experiments on a small radiosonde balloon.

An Electronic Nose is being developed at JPL and Caltech for use in environmental monitoring in the International Space Station. The Electronic Nose (ENose) is an array of 32 polymer film conductometric sensors; the pattern of response may be deconvoluted to identify contaminants in the environment. An engineering test model of the ENose was used to monitor the air of the Early Human Test experiment at Johnson Space Center for 49 days. Examination of the data recorded by the ENose shows that major excursions in the resistance recorded in the sensor array may be correlated with events recorded in the Test Logs of the Test Chamber.