GPS Micro Navigation and Communication System for Clusters of Micro and Nanosatellites

Formation flying will quickly revolutionize the way science, remote sensing and surveillance missions are performed in space, enabling a whole new range of applications for small satellites. Currently, there are numerous missions in the planning stages involving formation flying of a constellation of micro or nanosatellites. However, to truly achieve the goals of these formation-flying missions, an accurate means of relative ranging, determining time and position measurements, inter-satellite communications, and controlling the formation states is becoming critical. Today, while there are very expensive products available for positioning and attitude determination, none of them are capable of meeting the precise positioning accuracy and attitude determination requirements of formation flying, let alone the mass and power restrictions of these tiny space vehicles. This paper will address the needs of future formation flying missions by discussing a technology with integrated capabilities for communicating, relative ranging, and exchanging precise timing among spacecraft within the constellation. This system is being developed by integrating a Carrier Phase Differential GPS (CDGPS) navigation and attitude sensor with a low power, inexpensive, compact ranging and communications system. The result of this integration is a low-cost, robust, secure GPS micro navigation and communication system for micro and nanosatellite constellations

Cyanobacterial Harmful Algal Blooms: Chapter 1: An Overview of the Interagency, International Symposium on Cyanobacterial Harmful Algal Blooms (ISOC-HAB): Advancing the Scientific Understanding of Freshwater Harmful Algal Blooms

There is growing evidence that the spatial and temporal incidence of harmful algal blooms is increasing, posing potential risks to human health and ecosystem sustainability. Currently there are no US Federal guidelines, Water Quality Criteria and Standards, or regulations concerning the management of harmful algal blooms. Algal blooms in freshwater are predominantly cyanobacteria, some of which produce highly potent cyanotoxins. The US Congress mandated a Scientific Assessment of Freshwater Harmful Algal Blooms in the 2004 reauthorization of the Harmful Algal Blooms and Hypoxia Research and Control Act. To further the scientific understanding of freshwater harmful algal blooms, the US Environmental Protection Agency (EPA) established an interagency committee to organize the Interagency, International Symposium on Cyanobacterial Harmful Algal Blooms (ISOC-HAB). A theoretical framework to define scientific issues and a systems approach to implement the assessment and management of cyanobacterial harmful algal blooms were developed as organizing themes for the symposium. Seven major topic areas and 23 subtopics were addressed in Workgroups and platform sessions during the symposium. The primary charge given to platform presenters was to describe the state of the science in the subtopic areas, whereas the Workgroups were charged with identifying research that could be accomplished in the short- and long-term to reduce scientific uncertainties. The proceedings of the symposium, published in this monograph, are intended to inform policy determinations and the mandated Scientific Assessment by describing the scientific knowledge and areas of uncertainty concerning freshwater harmful algal blooms

Henry Watterson, The Coincidental Redeemer

The major conclusion of this thesis is that Henry Watterson, while representative of the Redeemer element, was the product of a Jacksonian, rather than a Whig, heritage which had an ideology quite similar to the Redeemer appeal. In determining his exact philosophy the study shows that the editor was quite different from his contemporaries in the New South in both the substance and integrity of his beliefs

Product Platform Concepts Applied to Small Satellites: A New Multipurpose Radio Concept by AeroAstro Inc.

AeroAstro Inc., with the development of their new multipurpose radio platform, has solved many of the communication problems faced by spacecraft system designers. With each new satellite application, engineering teams repeatedly address several communication requirements that are common to all satellite application. As part of a U.S. Air Force sponsored effort, AeroAstro’s Space Frame initiative is implementing product platform concepts to develop a family of radios that are modular, based on standard interfaces, and use an open architecture. The new multipurpose radio uses standard core modules that can be configured to meet a wide range of spacecraft radio applications. For example, modules for a receiver, a transmitter, a baseband processor and a power amplifier will be designed. Some of these modules will have differentiators, or selectable parameters. Once the design of these modules is mature, the design of a particular satellite radio is simply a matter of selecting the correct modules with the right parameters and interconnecting them. The new multipurpose radio reduces the time and cost required to meet the communication requirements of multiple spacecraft applications. This paper describes the new product platform approach and some of the subsystem functions imbedded in this multipurpose radio

AeroAstro’s X-Band Transponder – Meeting the Communication Needs of Tomorrow’s Small Spacecraft

This paper will discuss a number of technologies and design philosophies leveraged from commercial industry that AeroAstro has applied to the development of a new spacecraft communications subsystem. Although there has been a recent push toward reducing spacecraft mass and cost, there is no commercially available communications equipment that will significantly contribute to that reduction. While spacecraft mass has dropped more than an order of magnitude in the past ten years, radios have not followed this trend. AeroAstro is developing a highly integrated, power-efficient, low operating voltage X-Band telemetry transponder for small satellite applications. This design leverages emerging technology from the telecommunications industry, using RF component technology developed for digital wireless communications and Direct Broadcast Entertainment. By making use of these advances, and continuing development in a few key areas, AeroAstro’s transponder is designed specifically to provide low-cost, low-voltage, and low-mass earth-to-space communications. The X-Band radio under development includes a high scale of integration, a very low mass and volume, a high level of power efficiency, and the ability to operate from low voltage supplies. Flexibility is key to the design philosophy, and the communications equipment can be configured to satisfy a wide variety of missions