NASA - National Aeronautics and Space Administration

LISA co-observes with existing passive microwave sensors to identify sources of damaging radio frequency interference (RFI)

· 1200-1700 MHz using broadbeam spiral antenna
· Spectrum analyzer for full bandwidth monitoring of power spectral density
· 14 MHz (8+8 bit @ 20 MSPS) coherent sampling capability for waveform capture and analysis
· Flexible script command language for system control & experiment automation

The LIP (Lightning Instrument Package) measures lightning, electric fields, electric field changes, air conductivity. LIP provides real time electric field data for science and operations support.

The LIP is comprised of a set of optical and electrical sensors with a wide range of temporal, spatial, and spectral resolution to observe lightning and investigate electrical environments within and above thunderstorms. The instruments provide measurements of the air conductivity and vertical electric field above thunderstorms and provide estimates of the storm electric currents. In addition, LIP will detect total storm lightning and differentiate between intracloud and cloud-to-ground discharges. This data is used in studies of lightning/storm structure and lightning precipitation relationships.

The Large Area Collectors are flown on the ER-2 in support of the NASA-Johnson Space Flight Center Cosmic Dust Program. The LACs are used to collect comparatively unaltered cosmic dust from the stratosphere at ER-2 flight altitudes of 65,000 feet and above. Sufficient quantities of extraterrestrial materials are collected to allow chemical and mineralogical compositions of individual particles to be determined. Study of these materials whose sources may be comets, asteroid collisions, planetary impacts, and meteorite ablation provide valuable information about the origin and the history of the solar system.

The JPL Laser Hygrometer (JLH) is an autonomous spectrometer to measure atmospheric water vapor from airborne platforms. It is designed for high-altitude scientific flights of the NASA ER-2 aircraft to monitor upper tropospheric (UT) and lower stratospheric (LS) water vapor for climate studies, atmospheric chemistry, and satellite validation. JLH will participate in the NASA SEAC4RS field mission this year. The light source for JLH is a near-infrared distributed feedback (DFB) tunable diode laser that scans across a strong water vapor vibrational-rotational combination band absorption line in the 1.37 micrometer band. Both laser and detector are temperature‐stabilized on a thermoelectrically-cooled aluminum mount inside an evacuated metal housing. A long optical path is folded within a Herriott Cell for sensitivity to water vapor in the UT and LS. A Herriott cell is an off-axis multipass cell using two spherical mirrors [Altmann et al., 1981; Herriott et al., 1964]. The laser beam enters the Herriott cell through a hole in the mirror that is closest to the laser. The laser beam traverses many passes of the Herriott cell and then returns through the same mirror hole to impinge on a detector.

IRIS is an ultra sensive laser spectrometer for in situ detection of the isotopic composition of water vapor in the higher tropopause and the lower stratosphere. The isotope signals may be used to quantify troposphere-stratosphere exchange, and to study the water chemistry in the stratosphere. IRIS is based on the technique of optical-feedback cavity enhanced absorption spectroscopy. It uses a room temperature infrared laser, needing no crygens. The instrument combines a low weight (< 50 kg) and volume (< 50 L) with a low power consumption (< 200 W), making it uniquely suitable for future deployment on an Unmanned Aerial Vehicle.

INFLAME provides a direct measurement of the net flux, and requires high stability with much less stringent requirements on absolute accuracy, thereby removing the major impediment of existing measurements. The INFLAME instruments, deployed on small aircraft, will provide a direct measurement of the net flux radiative, flux divergences, and heating rates in clear sky, in the presence of aerosols, and in the presence of cloud particles.

The INFLAME instrument measures the net flux by using a low-resolution Fourier transform spectrometer (FTS) to observe the upward and downward flux simultaneously using the two inputs of the same instrument. The two complementary outputs of the FTS can be transformed to produce spectra proportional to the difference between the two inputs.

The Harvard CRDS/ICOS instrument is an absorption spectrometer that uses the relatively new and highly sensitive techniques of integrated cavity output spectroscopy (ICOS) and cavity ringdown spectroscopy (CRDS) with a high-finesse optical cavity and a cw quantum cascade laser (QCL) source. The primary spectroscopic technique employed is ICOS, in which intra-cavity absorption is measured from the steady-state output of the cavity. Light from a high power, tunable, single mode, solid-state laser source is coupled into a cavity consisting of two concave, highly reflective mirrors (R ≈ 0.9999), through which air continuously flows. The laser is scanned over a spectral region of 1–2 cm-1 containing an absorption feature, and the cavity output is detected by an LN2-cooled HgCdTe detector. The resultant output approximates an absorption spectrum with an effective pathlength of > 5 km, far greater than that of standard multipass Herriott or White cells.

The Hyperspectral Thermal Emissions Spectrometer (HyTES) instrument has 512 pixels across track with pixel sizes in the range of 5 to 50 m depending on aircraft flying height and 256 spectral channels between 7.5 and 12 µm. The HyTES design is built upon a Quantum Well Infrared Photodetector (QWIP) focal plane array (FPA) , a cryo-cooled Dyson Spectrometer and a high-efficiency, concave blazed grating, produced using E-beam lithography.

HyTES will be useful for a number of applications, including high-resolution surface temperature and emissivity measurements and volcano observations. HyTES measurements will also be used to help determine scientifically optimal band locations for the thermal infrared (TIR) instrument for the Decadal HyspIRI mission.

The design of the newly developed total water instrument is based on the same principles as the water vapor instrument, and is intended to fly in conjunction with it. Conceptually, the total water instrument can be thought of as containing four subsystems:
1. An inlet through which liquid and/or solid water particles can be brought into an instrument duct without perturbing the ambient particle density.
2. A heater that efficiently evaporates the liquid/solid water before it reaches the detection axis.
3. Ducting through which the air flows to the detection axis without perturbing the (total) water vapor mixing ratio.
4. A water vapor detection axis that accurately and precisely measures the total water content of the ambient air.