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System for Observing Dynamic Atmospheric Phenomena

System has drastically increased transmitter capability at much reduced cost. NASA’s Jet Propulsion Laboratory, Pasadena, California Existing observing systems are inadequate to measure a variety of dynamic atmospheric processes. Ground-based or airborne systems do not observe over sufficiently large regions to capture the context or time history of many phenomena. Space-based systems do not observe a specific region over sufficient duration with sufficient spatial resolution to capture the essential features of the phenomena. Radar systems are limited in what they can observe because of the need for scattering sources to be present in the observed volume.

Posted in: Briefs

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Covariance Analysis of Astrometric Alignment Estimation Architectures for Precision Dual-Spacecraft Formation Flying

A paper highlights analysis of proposed navigation systems and architectures for achieving precise dual-spacecraft astrometric alignment. The dynamics of dual-spacecraft relative motion, within a restricted n-body problem framework, are shown to reduce to a simple linear form for use in estimation filter design and error analysis for a deep space mission application, such as MASSIM (Milli-Arc-Second Structure Imager). This model is augmented with simplified measurement process models of relevant measurement types. These include inertial sensors, such as accelerometers and rate gyros, as well as optical alignment sensors, such as star and laser beacon trackers. A consider-state covariance analysis tool is developed from these process models and used to study the performance of proposed estimation architectures for the MASSIM application. This work develops a generic analysis methodology for evaluation of dual-spacecraft relative navigation systems and architectures for precise dual-spacecraft astrometric alignment.

Posted in: Briefs, TSP

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Automated Purgatoid Identification

An algorithm was developed that automatically processes images captured by the HiRISE camera on the Mars Reconnaissance Orbiter to identify and locate the presence of purgatoids in monochrome images.

Posted in: Briefs, TSP

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Interplanetary CubeSats

A report describes upgraded CubeSat satellite elements for the interplanetary environment, with solar sail propulsion and the interplanetary superhighway for navigation and maneuvering. They can host small, capable instruments and optical telecommunications on a mission to map the composition of a sequence of near-Earth asteroids and planetary bodies.

Posted in: Briefs, TSP

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Novel Hemispherical Dynamic Camera for EVAs

A novel optical design for imaging systems is able to achieve an ultra-wide field of view (UW-FOV) of up to 208°. The design uses an integrated optical design (IOD). The UW-FOV optics design reduces the wasted pixels by 49% when compared against the baseline fisheye lens. The IOD approach results in a design with superior optical performance and minimal distortion.

Posted in: Briefs

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Technique for Finding Retro-Reflectors in Flash LIDAR Imagery

Orbital rendezvous and docking of two spacecraft is a topic of continued interest to NASA. For crewed missions, it is frequently the case that the target is cooperative (i.e., is equipped with some sort of navigation aid). If one of the relative navigation instruments is a Flash LIDAR, then this aid may be a suite of retro-reflectors. One of the most difficult aspects of this problem (especially at close range) is finding the retro-reflectors in a Flash LIDAR image amongst a substantial amount of clutter.

Posted in: Briefs

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Spacecraft Line-of- Sight Stabilization Using LWIR Earth Signature

Applications could include remote science and planetary science missions, Earth surveillance and reconnaissance, and deep space optical communication. Until the time of this reporting, when a space vehicle required a reference signal for inertial pointing, the choices were a signal beacon from an Earth location, the Earth radiance in the visible spectrum, or a star tracker. However, limitations can arise from using these techniques. For example, the signal beacon suffers from limited signal power (either in RF or optical) and will constrain the application to limited ranges, errors due to stray-light and centroiding limit the accuracy of a star tracker, and the spatial/temporal variability of the Earth’s albedo and its illumination by the Sun introduces limitations when used in the visible or near infrared light.

Posted in: Briefs

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