Spectral properties of the Shroud of Turin.

Spectrophotometric results from the 1978 investigation of the Shroud of Turin are presented. The goals of the investigation were to characterize spectrally the body image in a region extending from the near UV to the near IR, to determine if the blood stains are actually blood, and to recommend storage parameters to prevent further degradation of the image. The bloodstained areas have the spectral characteristics of human hemoglobin. The image shows monotonically increasing (featureless) absorption with decreasing wavelength. The contrast is low: R(550 nm) = 0.85 of that for the background linen. Simulated aging by air baking reproduced the color of the background linen. Simultaneously, an invisible deposit of perspiration plus skin oils became visible and displayed a reflection spectrum closely resembling that of the body image. Lightly scorched areas on the Shroud are also somewhat similar spectrally, suggesting that a similar resultant chemistry is possible for dissimilar causes. A likely cause for the bo y image is cellulose degradation stimulated locally by natural or applied substances transferred to the Shroud.

Scattering defects in silver mirror coatings.

Scatter centers common to protected silver have been investigated on a variety of space flight quality mirrors. The defects have been characterized as to number density, size, location within the film layer structure, and dependence on illumination angle. In addition the total integrated scatter values as a function of wavelength, humidity test soak time, and temperature have been determined for some mirrors. These submicrometer sized defects are believed to be the precursors of silver corrosion spots. A mechanism for their generation is proposed, and measures to reduce their occurrence are suggested.

Beam splitter and reflection reducing coatings on ZnSe for 3-14 microm.

Achromatic coatings to provide wideband amplitude division and reflection reduction at 45 degrees incidence have been developed for the 3-14-microm region on CVD ZnSe. The application is directed toward interferometer spectrometers operating in environments that include spaceflight as well as laboratory. Results in good agreement with theoretical designs have been obtained.

Radiation induced transmission loss in optical materials.

Results are presented for a number of window materials, color filter glasses, birefringent crystals, and optical fibers. The transmission loss caused by exposure to Co(60) gamma or 10-MeV electron radiation is tabulated over the 400-900-nm wavelength region. The transmission loss is greatest at the shorter wavelengths, and its rate is maximum for most materials at dosages greater than 10(5) rad (Si).

Pioneer imaging photopolarimeter optical system.

The imaging photopolarimeter aboard the Pioneer 10 spacecraft en route to the vicinity of Jupiter is described. This instrument is capable of moderate resolution spin-scan imaging and high precision polarimetric and photometric mapping of Jupiter in red and blue light. The field of view can be selectively changed from 0.50 mrad square to 40 mrad square to accommodate resolution and radiance combinations ranging from the zodiacal background to that of Jupiter. The dynamic range (radiance) of the instrument is greater than 10(8). Optical materials were chosen to survive, with minimum degradation, the rigors of a nearly 2-year journey to Jupiter including transit through the Jovian trapped radiation belts. The optics are described in detail, and the operational system is outlined. The procedures for preflight and in-flight calibration are described, and some performance characteristics and preliminary flight results are presented.

Polarizing properties of pulverized materials with special reference to the lunar surface.

A review is presented of the application of polarimetry to the determination of the properties of the lunar surface layer by comparison with laboratory surfaces, from the time of Arago to the Apollo 11 sampling. The polarizing properties of pulverized volcanogenic products and chemicals, as they are determined by wavelength, particle size, phase angle, state of compaction, and composition, are studied. It is learned, through the study of the slope of the polarization/wavelength curve in the near uv, that the lunar surface must contain a large component of translucent rather than totally opaque particles. The lunar particles are basalt in composition, are less than 50 microm in size, and comprise a loosely arranged surface structure. Earth-based determinations are in good agreement with the Apollo 11 sampling results; thus these remote-sensing techniques are applicable to the studies of other planetary surfaces. Comparison between the surfaces of Mercury, some asteroids, and the moon is made.

An automatic polarimeter for space applications.

Under a NASA contract, a compact automatic polarimeter was developed as a pilot model for lunar and planetary missions by spacecraft. The polarimeter simultaneously analyzes linearly polarized light into four intensities from which the Stokes parameters I, Q, and U can be determined. The measurements are made automatically by an electronic observation sequencer and an automatic gain selector. Five wavelength bands between 1900 A and 6000A can be used, and each measurement is calibrated automatically. The successful operation during three high altitude balloon flights indicates that the design is sound, and that with modifications for rocket vibration it can be used in space missions. The feature of making simultaneous measurements makes it particularly useful on planetary scans with fly-by probes. Preliminary results on the wavelength dependence of the polarization of the whole lunar disk, obtained ground-based, between 2850 A and 5100 A are presented.

Solid organic filters for 2000 A to 3000 A.

Earlier work on the development of organic, narrow bandpass solution filters with transmittance maxima in the 2000-3000-A range is extended to the fabrication of solid filters using a polymethyl siloxane resin as the host material. Three transmission filters are described having maxima at 2250 A, 2265 A, and 2840 A, respectively, with bandwidths