A document describes cryogenic test architecture for the James Webb Space Telescope (JWST) integrated science instrument module (ISIM). The ISIM element primarily consists of a mechanical metering structure, three science instruments, and a fine guidance sensor. One of the critical optomechanical alignments is the co-registration of the optical telescope element (OTE) exit pupil with the entrance pupils of the ISIM instruments. The test architecture has been developed to verify that the ISIM...
Topics: NASA Technical Reports Server (NTRS), PUPILS, JAMES WEBB SPACE TELESCOPE, DEGREES OF FREEDOM,...
The design and analysis of a hybrid diffractive/refractive achromat for optical data storage is presented, beginning with a discussion of the construction and diffraction efficiency of surface relief diffractive lenses. The phase function, which defines a diffractive lens in much the same manner as a surface sag equation defines a refractive lens, is examined. The thin lens, or Sweatt, model of a diffractive lens is discussed, and equations are provided that allow conversion to and from the...
Topics: DTIC Archive, Kubalak, David A, ROCHESTER UNIV NY INST OF OPTICS, *OPTICAL STORAGE, OPTICAL DATA,...
A method for corrections of measurements of points of interests measured by beams of radiation propagating through stratified media including performance of ray-tracing of at least one ray lunched from a metrology instrument in a direction of an apparent point of interest, calculation a path length of the ray through stratified medium, and determination of coordinates of true position of the point interest using the at least one path length and the direction of propagation of the ray.
Topics: NASA Technical Reports Server (NTRS), BEAMS (RADIATION), CORRECTION, OPTICAL RADAR, RAY TRACING,...
Three phase plates were designed to simulate the JWST segmented primary mirror wavefront at three on-orbit alignment stages: coarse phasing, intermediate phasing, and fine phasing. The purpose is to verify JWST's on-orbit wavefront sensing capability. Amongst the three stages, coarse alignment is defined to have piston error between adjacent segments being 30 m to 300 m, intermediate being 0.4 m to 10 m, and fine is below 0.4 m. The phase plates were made of fused silica, and were assembled in...
Topics: NASA Technical Reports Server (NTRS), SEGMENTED MIRRORS, SIMULATORS, CALIBRATING, ALIGNMENT,...
Lidar is a useful tool for taking metrology measurements without the need for physical contact with the parts under test. Lidar instruments are aimed at a target using azimuth and elevation stages, then focus a beam of coherent, frequency modulated laser energy onto the target, such as the surface of a mechanical structure. Energy from the reflected beam is mixed with an optical reference signal that travels in a fiber path internal to the instrument, and the range to the target is calculated...
Topics: NASA Technical Reports Server (NTRS), OPTICAL RADAR, OPTICAL MEASUREMENT, METROLOGY, RADAR...
The NASA Goddard Space Flight Center (GSFC) and its partners have broad experience in the alignment of flight optical instruments and spacecraft structures. Over decades, GSFC developed alignment capabilities and techniques for a variety of optical and aerospace applications. In this paper, we provide an overview of a subset of the capabilities and techniques used on several recent projects in a \"toolbox\" format. We discuss a range of applications, from small-scale optical alignment...
Topics: Blake, Peter N., Bos, Brent J., Coulter, Phillip, Eichhorn, William L., Genesis Engineering...
NASA's James Webb Space Telescope (JWST) is a 6.6m diameter, segmented, deployable telescope for cryogenic IR space astronomy (~40K). The JWST Observatory includes the Optical Telescope Element (OTE) and the Integrated Science Instrument Module (ISIM) that contains four science instruments (SI) and the fine guider. The SIs are mounted to a composite metering structure. The SI and guider units were integrated to the ISIM structure and optically tested at the NASA Goddard Space Flight Center as a...
Topics: AK Aerospace Technology Corp., Adnet Systems, Inc., Antonille, Scott R., Arizona Univ., Aronstein,...
