Alexander J. Pertica

Space-based telescopes for actionable refinement of ephemeris pathfinder mission

The Space-based Telescopes for Actionable Refinement of Ephemeris (STARE) program will collect the information needed to help satellite operators avoid collisions in space by using a network of nano- satellites to determine more accurate trajectories for selected space objects orbiting the Earth. In the first phase of the STARE program, two pathfinder cube-satellites (CubeSats) equipped with an optical ima- ging payload are being developed and deployed to demonstrate the main elements of the STARE concept. We first give an overview of the STARE program. The details of the optical imaging payload for the STARE pathfinder CubeSats are then described, followed by a description of the track detection algorithm that will be used on the images it acquires. Finally, simulation results that highlight the effectiveness of the mission are presented.

Intelligent sensor tasking for space collision mitigation

Orbital collisions pose a hazard to space operations. Using a high performance computer modeling and simulation environment for space situational awareness, we explore a new paradigm for improving satellite conjunction analysis by obtaining more precise orbital information only for those objects that pose a collision risk greater than a defined threshold to a specific set of satellites during a specified time interval. In particular, we assess the improvement in the quality of the conjunction analysis that can be achieved using a distributed network of ground-based telescopes.

Absolute intensity, high resolution spectrum of the Vortek arc lamp and its spectral match to Nd:YAG bands

The high-resolution absolute-intensity spectrum of a Vortek-arc lamp is obtained in order to evaluate the lamp as a candidate for a pump source for crystal-laser amplifiers. Spectra are also obtained at lower resolution for Ar-Kr and Ar-Xe mixtures. These spectra are convolved with the Nd:YAG absorption cross section assuming YAG crystal thickness of 0.5 cm and doping of 2 x 10 to the 20th/cu cm. Emphasis is placed on wavelength and intensity calibrations, assembling the spectral regions, and low-resolution spectra. A spectral overlap with Nd:YAG bands is discussed, as well as pulsed operation, lamp-tube filtering, and electrical efficiency. It is noted that pulsing of the lamp should be possible and may provide further improvements in laser operation.