Browse Topic: Telescopes
The purpose of this work was to develop and demonstrate technologies for a next-generation, efficient, swath-mapping space laser altimeter. The Lidar Surface Topography (LIST) mission concept allows simultaneous measurements of 5-meter-spatial-resolution topography and vegetation vertical structure with decimeter vertical precision in an elevationimaging swath several kilometers wide from a 400-km-altitude Earth orbit. To advance and demonstrate needed technologies for the LIST mission, the Airborne LIST Simulator (ALISTS) pathfinder instrument was developed. ALISTS is a micropulse, single photon-sensitive waveform recording system based on a new and highly efficient laser measurement approach utilizing emerging laser transmitter and detector technologies.
The Integrated Science Instrument Module (ISIM) Ground Support System (IGSS) Equation Processor (IEP) allows for the general production of “derived” telemetry products in the Raytheon Eclipse ground system used to support the James Webb Space Telescope (JWST) project. The IEP works alongside the Raytheon-provided equation-processing system but provides for support of string data types that the existing equation processing does not support. The string data type production is required to support the manipulation of JWST string telemetry data types, and for the production of string data types to produce readable time conversions from a binary value to year, day, hour, minute, second format that can be directly viewed on real-time telemetry display pages. The user writes equation scripts using the Tool Command Language (TCL) and specifies as part of the definition how the equation is triggered and what the results should look like. The TCL scripting language provides for a fully featured
The Neo-Geography Toolkit (NGT) is a collection of open-source software tools for the automated processing of geospatial data, including images and maps. It can process raw raster data from remote sensing instruments and transform it into useful cartographic products such as visible image base maps, topographic models, etc. It can also perform data processing on extremely large geospatial data sets (up to several tens of terabytes) via parallel processing pipelines. Finally, it can transform raw metadata, vector data, and geo-tagged datasets into standard Neo-Geography data formats such as KML.
Space-based interferometry missions have the potential to revolutionize imaging and astrometry, providing observations of unprecedented accuracy. Realizing the full potential of these interferometers poses several significant technological challenges. These include the efficient maneuvering of multiple collectors to various baselines to make the requisite observations; regulating the path-length of science light from the collecting telescopes to the combining instrument with nanometer accuracy, despite the presence of vibration induced by internal and external disturbance sources; and demonstrating through hardware-in-the-loop simulation that the numerous spacecraft (SC) subsystems can be coordinated to perform such challenging observations in a precise, efficient, and robust manner.
This technology enables accurate calibration of a large Computer Generated Hologram (CGH) fabricated without great accuracy, such that the CGH still measures an aspheric surface to an excellent accuracy of a couple of nm rms. The goal is the creation of software for generating a calibration map, and the fabrication of a couple of 9-in. (≈22.5-cm)-diameter CGHs to experimentally verify the technology. Use of CGHs in testing aspheric surfaces provides many advantages, such as better imaging, lower mapping distortion, and much higher-quality substrates.
Orbiting a large number of satellites in fixed formations will be critical to many future space missions, especially large-scale interferometers, telescopes, antennas, and gravity wave detectors. Consequently, extensive research has been devoted over the last 20 years to formation flying architectures, concentrating not only on the mission objective, but also on the technologies required to achieve a stable satellite formation. Several proposals have been suggested for determining the location of the satellites, but the more difficult problem is developing a system that can hold the satellites at those desired locations and orientations. The two most common solutions are to use microthrusters, though these require propellant and will eventually be depleted, or to choose orbital patterns that minimize relative perturbations, but for highly precise positioning, this is not adequate. Neither of these approaches solves the problem for long-duration missions such as a multi-element
Wafer-level integration was employed to mount the microshutter array for the James Webb Space Telescope (JWST) and the detector-read-out hybrid for TIRS (Thermal Infrared Sensor). In the case of the JWST substrate, two conductors (polysilicon and aluminum) separated by a silicon oxide insulating layer were fabricated on a roughly 85-mm-square silicon wafer. The size of the substrate, the density and length of the conductive traces, and the requirement of zero shorts and zero opens on the finished device necessitated nearly impossible cleanroom requirements. Techniques were developed to repair the inevitable shorts and opens created during the wafer fabrication process. The wafers were repaired to zero shorts and zero opens without degradation of device performance.
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