Lance M. Simms

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.

Autonomous subpixel satellite track end point determination for space-based images.

An algorithm for determining satellite track end points with subpixel resolution in spaced-based images is presented. The algorithm allows for significant curvature in the imaged track due to rotation of the spacecraft capturing the image. The motivation behind the subpixel end point determination is first presented, followed by a description of the methodology used. Results from running the algorithm on real ground-based and simulated spaced-based images are shown to highlight its effectiveness.

Optical payload for the STARE 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 imaging payload are being developed and deployed to demonstrate the main elements of the STARE concept. In this paper, we first give an overview of the STARE program. We then describe the details of the optical imaging payload for the STARE pathfinder CubeSats, including the optical design and the sensor characterization. Finally, we discuss the track detection algorithm that will be used on the images acquired by the payload.

CXBN: A Blueprint for an Improved Measurement of the Cosmological X-Ray Background

A precise measurement of the Cosmic X-ray Background (CXB) is crucial for constraining models of the evolution and composition of the universe. While several large, expensive satellites have measured the CXB as a secondary mission, there is still disagreement about normalization of its spectrum. The Cosmic X-ray Background NanoSat (CXBN) is a small, low-cost satellite whose primary goal is to measure the CXB over its two-year lifetime. Benefiting from a low instrument-induced background due to its small mass and size, CXBN will use a novel, pixelated Cadmium Zinc Telluride (CZT) detector with energy resolution < 1 keV over the range 1-60 keV to measure the CXBN with unprecedented accuracy. This paper describes CXBN and its science payload, including the GEANT4 model that has been used to predict overall performance and the backgrounds from secondary particles in Low Earth Orbit. It also addresses the strategy for scanning the sky and calibrating the data, and presents the expected results over the two-year mission lifetime.