Abstract: A method is described for selecting optical materials to use in designing color-corrected optical systems. Various dioptric, catadioptric and anamorphic optical systems are described, which use only two different types of optical materials to obtain precise axial color correction at three, four or five wavelengths (depending upon the particular optical materials), with only very small chromatic aberration occurring at wavelengths between the precisely color-corrected wavelengths. Examples of color-corrected lens systems comprising more than two glasses are also described.

Abstract: Mechanical stress applied to a crystal (10) by a procedure for forming a bond (13) between an electrical connector (12) and a metallized surface (11) of the crystal (10) is measured to obtain a quantitative indication of the quality of the bond (13). A beam of optical radiation generated by an illuminator (21) is divided by a first beamsplitter (22) into a first component and a second component. The power of the first component is measured by a first detector (23). The second component is circularly polarized by a circular polarizer (24), collimated by an imaging lens (25), and directed as an incident beam along an optical path through the crystal (10) to the metallized surface (11) in the vicinity of the bond (13). The metallized surface (11) reflects the incident beam back along the same optical path as a return beam.

Abstract: A catadioptric optical imaging system comprises a dioptric assembly (20) and a catoptric assembly (21), which are positioned with respect to each other to form an imaging system of long focal length. The dioptric assembly (20) comprises two confocal paraboloidal mirrors (22, 23) arranged to form a telescope of the Mersenne type. The catoptric assembly (21) comprises lens elements arranged in two groups, viz., a field group (25) and a relay group (26), which are coaxially disposed with respect to the dioptric assembly (20). Only two different optical materials, viz., calcium fluoride crystal and Hoya LAC7 glass, are used in making the lens elements of the dioptric assembly (20). The dioptric assembly (20) is color-corrected at five wavelengths and has only negligible secondary and higher-order spectra in a wavelength band extending from the ultraviolet region to the near infrared region of the optical spectrum.

Abstract: A method is described for selecting optical materials to use in designing color-corrected optical systems. Various dioptric, catadioptric and anamorphic optical systems are described, which use only two different types of optical materials to obtain precise axial color correction at three, four or five wavelengths (depending upon the particular optical materials), with only very small chromatic aberration occurring at wavelengths between the precisely color-corrected wavelengths. Examples of color-corrected lens systems comprising more than two glasses are also described.

Abstract: An exterior surface portion of a metal tube (30) is bonded to a surface portion of a bore (11) in a metal tubesheet (10) by detonating an explosive bonding charge (31) inside the tube (30) adjacent a front face (13) of the tubesheet (10). The bonding charge (31) consists of nitroguanidine, and is contained within a polypropylene container comprising a cup structure (21) and a header structure (22). The cup structure (21) forms a receptacle for the bonding charge (31), and positions the bonding charge (31) at the proper depth within the tube (30) to achieve the desired bonding effect. The header structure (22) overlies and shapes the bonding charge (31), and contains a transfer charge (44) and a firing charge (45) for initiating detonation of the bonding charge (31). A firing assembly for initiating detonations of firing charges (45) in tubes (30) arranged in a plurality of linear arrays comprises a corresponding plurality of firing rails (24) and an initiation rail (27).

Abstract: A method is described for selecting optical materials to use in designing color-corrected optical systems. Various dioptric, catadioptric and anamorphic optical systems are described, which use only two different types of optical materials to obtain precise axial color correction at three, four or five wavelengths (depending upon the particular optical materials), with only very small chromatic aberration occurring at wavelengths between the precisely color-corrected wavelengths. Examples of color-corrected lens systems comprising more than two glasses are also described.

Abstract: A probe (10) inductively couples radio-frequency electromagnetic energy into a test piece that is made of a multi-ply graphite-epoxy composite material whose fiber volume, ply count and/or thickness are to be measured. The probe (10) and the test piece form a system characterized by an electrical impedance vector, whose magnitude and phase are determined by the composition of the test piece. A frequency synthesizer (16) drives a compensating circuit (15), which applies the output of the frequency synthesizer (16) to the probe (10). The waveform and frequency of the frequency synthesizer (16) are selected to optimize the amount of energy coupled from the probe (10) into the test piece.

Abstract: A method is described for selecting optical materials to use in designing color-corrected optical systems. Various dioptric, catadioptric and anamorphic optical systems are described, which use only two different types of optical materials to obtain precise axial color correction at three, four or five wavelengths (depending upon the particular optical materials), with only very small chromatic aberration occurring at wavelengths between the precisely color-corrected wavelengths. Examples of color-corrected lens systems comprising more than two glasses are also described.

Abstract: An apparatus (10) for dispensing struts (11 and 12) for use by an astronaut in erecting a truss structure in extraterrestrial space comprises a frame to which a platform (16) is attached. The astronaut anchors himself to the platform (16) while erecting the truss structure. Pairs of retainer assemblies for securing opposite ends of struts of different lengths, i.e., the pair of retainer assemblies (22 and 23) for the struts (11), and the pair of retainer assemblies (22' and 23') for the struts (12), are also attached to the frame. One retainer assembly (22 or 22') from each pair is positioned within the astronaut's reach when he is anchored to the platform (16), and the other retainer assembly (23 or 23') from each pair is positioned remote from the astronaut's reach. Each of the remote retainer assemblies (23 and 23') comprises a plurality of spring-loaded receptacles (41) for receiving one end of the corresponding struts (11 or 12).

Abstract: A catadioptric optical imaging system comprises a dioptric assembly (20) and a catoptric assembly (21), which are positioned with respect to each other to form an imaging system of long focal length. The dioptric assembly (20) comprises two confocal paraboloidal mirrors (22, 23) arranged to form a telescope of the Mersenne type. The catoptric assembly (21) comprises lens elements arranged in two groups, viz., a field group (25) and a relay group (26), which are coaxially disposed with respect to the dioptric assembly (20). Only two different optical materials, viz., calcium fluoride crystal and Hoya LAC7 glass, are used in making the lens elements of the dioptric assembly (20). The dioptric assembly (20) is color-corrected at five wavelengths and has only negligible secondary and higher-order spectra in a wavelength band extending from the ultraviolet region to the near infrared region of the optical spectrum.

Abstract: In a liquid-propellant management system for providing substantially gas-free liquid propellant to thrusters of a space vehicle, a storage tank (10) has an opening (11) through which liquid propellant is delivered via a line (13) to the thrusters. A trap (14) is secured within the tank (10) adjacent the opening (11). and an exit port (15) of the trap (14) is aligned with the opening (11) of the tank (10). A liner (16) is secured inside the trap(14) to define a volume between an interior surface portion of the trap (14) and the liner (16), which volume communicates via the exit port (15) and the opening (11) with the line (13). Liquid propellant enters into the trap (14) through an inlet window screen (27), and passes through porous windows (28) in the liner (16) into the volume between the trap (14) and the liner (16). Vanes (19) are secured to the exterior surface of the trap (14) and extend into the interior of the tank (14) and the liner (16).

Abstract: A polarizing cube beamsplitter, which is designed for infrared applications, comprises two 45.degree. prisms made of ZnSe. A first anti-reflection layer, which is a Herpin equivalent layer consisting of the triad of sublayers ZnS-ZnSe-Zns, is deposited onto the hypotenuse of a first one of the prisms. Then, a polarizing stack consisting of a plurality of pairs of thin-film layers of alternating high and low refractive indices is formed on the first anti-reflection layer. One layer in each pair of thin-film layers in the polarizing stack is a Herpin equivalent layer consisting of the triad of sub-layers Te-ZnSe-Te, and the other layer in each pair is a thin film of ZnSe. A layer of prism material ZnSe, which is thick enough to be optically polished, is then formed on the second anti-reflection layer. The hypotenuse of the second prism is likewise optically polished, and is pressed onto the optically polished layer of prism material to form a bond. The resulting beamsplitter is of cubic configuration.

Abstract: A plurality of sample beam wavefronts derived from selected portions of a wide-aperture outgoing optical beam wavefront enter an entrance pupil (11) located adjacent a focal surface (12) on which the sample beams are individually focussed. A relay lens system (13) transmits the sample beams to a beam splitter (14), which divides each of the sample beams into an undeviated component and a diviated component. The undeviated components of the various sample beams image the entrance pupil (11) on a first scanning mirror (15), and the deviated components image the entrance pupil (11) on a second scanning mirror (16). The focal surface (12) is reimaged by the relay lens system (13) onto focal planes (17 and 18), respectively, so that the foci of the individual sample beams appear as spots on the focal planes (17 and 18).

Abstract: A lens doublet comprising a positive lens element made of calcium fluoride crystal and a negative lens element made of Schott infrared transmitting glass IRGN6 enables an object to be imaged at four wavelengths in the visible region, or at four wavelengths in the near-infrared region, or at five wavelengths in a band extending from the visible to the near-infrared region of the electromagnetic spectrum. The doublet has practically negligible secondary and higher-order spectra throughout these spectral regions.

Abstract: A compact antenna for an extra-atmospheric vehicle is sufficiently rugged to withstand the rigors of atmospheric re-entry, and is capable of transmitting and receiving radio-frequency signals with selectable polarizations over a broad frequency bandwidth.

Abstract: A method is described for selecting optical materials to use in designing color-corrected optical systems. Various dioptric, catadioptric and anamorphic optical systems are described, which use only two different types of optical materials to obtain precise axial color correction at three, four or five wavelengths (depending upon the particular optical materials), with only very small chromatic aberration occurring at wavelengths between the precisely color-corrected wavelengths. Examples of color-corrected lens systems comprising more than two glasses are also described.

Abstract: Three different embodiments are shown of a photographic objective comprising only six lens elements, which is made of three different optical glasses, and which is well-corrected for both monochromatic and chromatic aberrations and has only negligible secondary and higher-order spectra in a wavelength band extending from the visible to the near infrared regions of the electromagnetic spectrum. The photographic objective is also color-corrected at four widely separated wavelengths in that band. The first embodiment is optimized for a 200 mm focal length at a relative aperture of f/4 over a 12.degree. field of view. The second embodiment is optimized for a 200 mm focal length at a relative aperture of f/5 over a 20.degree. field of view. The third embodiment is optimized for a 200 mm focal length at a relative aperture of f/4 over a 12.degree. field of view.

Abstract: A method is described for selecting optical materials to use in designing color-corrected optical systems. Various dioptric, catadioptric and anamorphic optical systems are described, which use only two different types of optical materials to obtain precise axial color correction at three, four or five wavelengths (depending upon the particular optical materials), with only very small chromatic aberration occurring at wavelengths between the precisely color-corrected wavelengths. Examples of color-corrected lens systems comprising more than two glasses are also described.

Abstract: A scan-shear interferometer comprises a beamsplitter (11) for dividing an optical beam into a transmitted component I and a reflected component II, which are propagated in opposite directions along a triangular portion of an optical path defined by mirrors (12) and (13) back to the beamsplitter (11), from which the beam component I is transmitted and the beam component II is reflected to a mirror (14), which reflects the beam components I and II coincidentally to form pupils on an interference plane at a photodetector device (15). A rotating prism (16) is positioned so that each of the beam components I and II makes a double pass through the prism (16) before reaching the interference plane. Rotation of the prism (16) causes the pupil formed by the beam component II to remain stationary, and causes the pupil formed by the beam component I to move across the stationary pupil along a scan axis on the interference plane.

Abstract: A photographic objective comprising six lens elements is well-corrected for both monochromatic and chromatic aberrations, and is color-corrected at four wavelengths in a band extending from the visible to the near infrared regions of the electromagnetic spectrum with only negligible secondary and high-order spectra at wavelength between those for which color correction is achieved. The design form for the objective has been optimized for a focal length of 200 mm at an aperture ratio of f/4 and a field of view of 12.degree. without vignetting.