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Past Conference Papers:
Payloads and Sensors
| Paper Number RS6-2008-3001: Technology Development for Lightweight L-Band SAR | |
| Mark Webster (Ball Aerospace & Technologies Corp.), Dean Paschen (Ball Aerospace & Technologies Corp.), Mark Leifer (Ball Aerospace & Technologies Corp.), David Murphy (ATK Space Systems), Gary Heinemann (ATK Space Systems) | |
| View/Download:Presentation | Paper | |
| Abstract: The ORS Payload Development Initiative awarded 14 contracts to develop basic to complex technologies for potential TacSat missions. The largest of the complex awards, announced in February of 2007, went to Ball Aerospace and its partner ATK to perform development and risk reduction for a light-weight L-Band Synthetic Aperture Radar antenna. The program, started in April of 2007, has focused on determining the most practical and highest-performing configuration for the antenna and in reducing risk and increasing feasibility of the overall design. The motivation for this L-band SAR, which can provide worldwide coverage daily with only two satellites, is to enable perceptive monitoring of near-real-time changes over broad regions of interest. Where further investigation is required, this would be provided by tasking more focused sensors. In developing the L-Band SAR, Ball has focused on the distributed architecture design of the radiating aperture and ATK has focused on the lightweight backing structure and deployment systems. The optimized design consists of modular tiles of 2X2 radiating elements with transmit and receive functionality provided by local electronics. 416 of these “quad” module assemblies (QMAs) are mounted on stable lightweight composite panels to form a contiguous 28 m2 aperture, with linking deployment mechanization that is derivative of heritage solar array designs. The program is preparing a complete design review documentation package and building proof of concept models that will be used to validate the capabilities of the antenna in the relevant environment. The paper will review the system design and present the results of the engineering model tests. The antenna unfolds on orbit into a 2-m x 14-m array, an aperture size in line with heritage L-band SAR systems; however, operational concepts have been developed that achieve ambiguity to signal performance levels typical of a much larger system . Cost is further minimized through modularity and the extensive use of COTS components. Reliability is insured by designing for massive parallelism and graceful degradation with amplifiers, T/R switches, phase shifters, attenuators and combiner/splitters on the QMA behind the radiating elements. Use of lightweight bonded honeycomb structures for the QMAs and backing panels will keep the weight of the antenna, including cabling, and deployment structure, below 7.5 kg/m2. The approach promises high performance at low cost. A prototype T/R module has demonstrated power output of 2W/element at any selectable polarization angle from H through V, resulting in array transmit power in excess of 3 kW. | |
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| Paper Number RS6-2008-3002: OASIS; Adaptation of an Operational Airborne Sensor for Responsive Space | |
| Bill Cidzik (ISR Systems Division, Goodrich Corporation), Charles Cox (ISR Systems Division, Goodrich Corporation), David Flynn (ISR Systems Division, Goodrich Corporation), Phil Giguere (ISR Systems Division, Goodrich Corporation) | |
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| Abstract: Existing airborne ISR systems provide operationally responsive ISR to the warfighter using mature sensors and existing infrastructures for tasking and data dissemination. The world's most capable system is flown on the U2 reconnaissance aircraft, collecting high resolution multispectral imagery in the visible and infrared spectrums that is communicated via CDL and is compatible with the DCGS ground infrastructure. Under contract to NRL, Goodrich has matured an ORS version of this sensor that retains the spectral imaging capabilities and CDL/DGGS TPED compatibility. The target application for this sensor is broad area search, combining a 400 km field of regard with 13 km wide image swaths at NIIRS 4 to provide persistent sampling of regions of interest. This paper summarizes the Sensor capabilities and documents the configuration and interfaces compatible with ORS class buses and launch vehicles. It also illustrates example collection modes and data products. | |
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| Paper Number RS6-2008-3005: WiSAR: A New Solution for High-Performance, Smallsat-Based Synthetic Aperture Radar Missions | |
| Peter Fox (MDA Corporation), Kenneth James (MDA Corporation), Alan Thompson (MDA Corporation) | |
| View/Download:Presentation | Paper | |
| Abstract: Cost effective, responsive Synthetic Aperture Radar (SAR) missions will only be possible when technology-enabled breakthroughs and efficiencies in manufacturing allow SAR satellites to be rapidly deployed on low-cost launch vehicles. This will be achievable when SAR satellites can be built at substantially lower mass and for significantly lower cost than current technologies allow. The key challenge to date has been in developing low cost, low mass phased array antenna technology without compromising resolution and performance. MDA’s Wireless Synthetic Aperture Radar (WiSAR™) is a new SAR antenna technology that offers leading-edge performance in both X- and C-band at significant reductions in cost and mass over the conventional state of the art. The WiSAR solution uses proven off-the-shelf technologies from the automotive and terrestrial wireless communication industries to enable an innovative space-fed active lens architecture that replaces the heavier and bulkier traditional constrained feed design. Key elements of the WiSAR payload include: self-contained active antenna nodes; low cost RF radiators; thin, lightweight, easily deployed antenna panels; and RF ranging for dynamic antenna distortion compensation. This paper will describe the WiSAR payload technology and the results of a project to build, test and operate a fully functioning C-band prototype WiSAR phased array antenna. | |
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| Paper Number RS6-2008-4007: Very High Resolution Imaging Using Small Satellites | |
| Stuart Eves (Surrey Satellite Technology) | |
| View/Download:Presentation | Paper | |
| Abstract: The paper will discuss the techniques required to deliver sub metre imaging from a small satellite, (with a total mass of less than 500 kg), commencing with an analysis of the trade-off between orbit height, image resolution and the lifetime of the system. This initial trade-off is required to identify the most appropriate operational altitudes associated with different orbit maintenance strategies. Also included in the discussion will be the high-level optical system design, showing how simpler, on-axis optical designs can achieve the required performance without involving the complexities, time constraints, and associated higher costs, of aspherical, off-axis mirror designs. Some of the trade-offs associated with detector design will also be addressed, including the potential need for active attitude control during imaging to control the read-out rate required from the sensor. The paper will cover the mechanical engineering challenges of flying a sophisticated optical bench into orbit, and the modes of operation that can be supported using such a concept. The paper will also indicate the sort of performance that could be derived from a similar satellite designed to operate in the IR rather than the optical spectrum. | |
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| Paper Number RS6-2008-6001: Spacecraft-to-Spacecraft Subsystem Modularization for Operationally Responsive Space | |
| Manny Nimelman (MDA), Andrew Allen (MDA ), Catherine Erkorkmaz (MDA), Andrew Ogilvie (MDA) | |
| View/Download:Presentation | Paper | |
| Abstract: This paper discusses the need for a modular and reconfigurable architecture for rendezvous, proximity operations, docking, and spacecraft servicing operations to support Operationally Responsive Space (ORS) missions. The motivation for ORS is be able to respond quickly to new satellite needs, either through rapid exploitation of existing assets in orbit, or through rapid assembly and launch of satellites with requisite payloads while exercising the bare minimum of commissioning and check-out of the integrated flight configuration. Many ORS missions will have tactical needs that include situational awareness, inspection, and close-range proximity operations with other spacecraft, and even docking and servicing operations to support upgrades of existing satellites and assets in support of ORS mission operations. These missions have a spectrum of requirements for fault tolerance, imaging capability, range-to-target, accuracy, and cost, but they can share a common set of sensor systems, avionics, physical interfaces, and numerous other spacecraft subsystems. As a specific example, ORS would greatly benefit from a common modular and reconfigurable architecture permitting users to select payloads from a common pool of plug-and-play elements to support rendezvous, proximity operations, inspection (passive or active), and/or docking. The paper discusses the requirements of an ORS reconfigurable architecture, focusing on the modules required for this particular set of operations. The starting point for this architecture is a spacecraft infrastructure that includes standardized interfaces for power, data, video, and standardized operating protocols for architecture elements. MDA has identified necessary elements for this architecture which include standard satellite navigation and attitude control sensors including GPS, startrackers, IMUs/IRUs, range and pose sensor solutions, imaging systems, fault-tolerant avionics, and physical interfaces for docking and servicing. The architecture is extensible to include different configurations of a given sensor, with a baseline solution and a set of plug-and-play upgrades based on required sensor capabilities. This paper also presents technologies developed through MDA programs that support this architecture and identifies areas requiring further technology development. MDA capabilities combine demonstrated spaceflight experience in the design of high reliability, mission critical systems with experience in decoupling system functions in order to package avionics and sensor systems as modular Orbital Replacement Units (ORUs) and in designing standardized, non-proprietary interfaces. These capabilities can address both the ORS objectives of quickly integrating new satellites, and being able to adapt existing on-orbit assets. In addition, MDA’s experience in the development of many high-TRL sensor solutions promising benefits for ORS missions will be used to illustrate the ORU design process. Finally, the paper addresses a concept for a high fidelity plug-and-play simulator that would allow for rapid prototyping and straightforward integration and test of different payload configurations. Such a simulator would allow a set of launch-ready subsystems to be integrated, verified, and launched in minimal time. | |
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