ALBERT

Description: Real-time identification of tissue would improve procedures such as stereotactic brain biopsy (SBX), functional and implantation neurosurgery, and brain tumor excision. To standard SBX equipment has been added: (1) computer-controlled stepper motors to drive the biopsy needle/probe precisely; (2) multiple microprobes to track tissue density, detect blood vessels and changes in blood flow, and distinguish the various tissues being penetrated; (3) neural net learning programs to allow real-time comparisons of current data with a normative data bank; (4) three-dimensional graphic displays to follow the probe as it traverses brain tissue. The probe can differentiate substances such as pig brain, differing consistencies of the 'brain-like' foodstuff tofu, and gels made to simulate brain, as well as detect blood vessels imbedded in these substances. Multimodality probes should improve the safety, efficacy, and diagnostic accuracy of SBX and other neurosurgical procedures.

Description: AVIRIS is a facility consisting of a flight system, a ground data system, a calibration facility, and a full-time operations team. The facility was developed by JPL under funding from NASA. NASA also provides funding for operations and maintenance. The flight system is a whisk-broom imager that acquires data in 224 narrow, contiguous spectral bands covering the solar reflected portion of the electromagnetic spectrum. It is flown aboard the NASA high altitude ER-2 research aircraft. The ground data system is a facility dedicated to the processing and distribution of data acquired by AVIRIS. It operates year round at JPL. The calibration facility consists of a calibration laboratory at JPL and a suite of field instruments and procedures for performing inflight calibration of AVIRIS. A small team of engineers, technicians, and scientists supports a yearly operations schedule that includes 6 months of flight operations, 6 months of routine ground maintenance of the flight system, and year-round data processing and distribution. Details of the AVIRIS system, its performance history, and future plans are described.

Description: An upgraded version of AVIRIS, an airborne imaging spectrometer based on a whiskbroom-type scanner coupled via optical fibers to four dispersive spectrometers, that has been in operation since 1987 is described. Emphasis is placed on specific AVIRIS subsystems including foreoptics, fiber optics, and an in-flight reference source; spectrometers and detector dewars; a scan drive mechanism; a signal chain; digital electronics; a tape recorder; calibration systems; and ground support requirements.

Description: The use of a gyrotron for space power beaming, especially in the form of a lunar orbiting power station is discussed. The advantages of phased array power beaming, output power, and the design of a quasi-optical gyrotron are discussed.

Description: Discovery of a widespread horizon of shock-deformed volcaniclastic ejecta preserved in Late Proterozoic (approx. 600 Ma) shales in South Australia and its probable link to the Acraman impact structure in the Middle Proterozoic Gawler Range. Volcanics provide a rare opportunity to study the effects of a major terrestrial impact, including the sedimentology and distribution of an ejecta blanket and its precious-metal signature. The ejecta horizon occurs in the Bunyeroo Formation at many localities within the Adelaide Geosyncline, including the Wearing Hills, which are approx. 350 km northeast of the Acraman impact site. Following a search at the same stratigraphic level in other basins in South Australia, the ejecta has been located within the Lower Rodda beds of the Officer Basin, extending the limits of the ejecta to approx. 470 km northwest of the Acraman impact structure. The ejecta is therefore widely dispersed, and provides an important chronostratigraphic marker enabling precise correlation of Late Proterozoic sequences in southern Australia. In summary, the Bunyeroo ejecta is unique as the only known example of a widely dispersed, coarse-grained ejecta blanket that is, moreover, strongly linked to a known major impact structure. The marked Ir-PGE anomalies in the ejecta horizon provide support for the hypothesis that meteorite impact events can produce Ir anomalies interrestrial sediments. The findings also indicate that Ir can be mobilized and concentrated in sediments by low-temperature diagenetic processes. The identification of ejecta horizons in sedimentary rocks therefore should be based on the coincidence of shock-metamorphic features in the detritus and clear Ir anomalies.

Description: Results are presented of the assessment of AVIRIS performance during the 1987 flight season by the AVIRIS project and the earth scientists who were chartered by NASA to conduct an independent data quality and sensor performance evaluation. The AVIRIS evaluation program began in late June 1987 with the sensor meeting most of its design requirements except for signal-to-noise ratio in the fourth spectrometer, which was about half of the required level. Several events related to parts failures and design flaws further reduced sensor performance over the flight season. Substantial agreement was found between the assessments by the project and the independent investigators of the effects of these various factors. A summary of the engineering work that is being done to raise AVIRIS performance to its required level is given. In spite of degrading data quality over the flight season, several exciting scientific results were obtained from the data. These include the mapping of the spatial variation of atmospheric precipitable water, detection of environmentally-induced shifts in the spectral red edge of stressed vegetation, detection of spectral features related to pigment, leaf water and ligno-cellulose absorptions in plants, and the identification of many diagnostic mineral absorption features in a variety of geological settings.

Description: The AVIRIS instrument has been designed to do high spectral resolution remote sensing of the Earth. Utilizing both silicon and indium antimonide line array detectors, AVIRIS covers the spectral region from 0.41 to 2.45 microns in 10-nm bands. It was designed to fly aboard NASA's U-2 and ER-2 aircraft, where it will simulate the performance of future spacecraft instrumentation. Flying at an altitude of 20 km, it has an instantaneous field of view of 20 m and views a swath over 10 km wide. With an ability to record 40 minutes of data, it can, during a single flight, capture 500 km of flight line.

Description: A brief review is given of daily operations in the airline business, with emphasis on the decisions made by pilots and the information used to make those decisions. Various wind shears are discussed as they affect daily operations. The discussion of tools focuses on airborne reactive and predictive systems. The escape maneuver used to fly out of a severe windshear is from a pilot's point of view.