Session XI: Advanced Technologies 2

Chair: John Monahan – RT Logic

Thursday, August 14, 2008

8:30 a.m.A Miniaturized Nanosatellite VHF / UHF Communications System: Wouter Jan Ubbels, A.R. Bonnema, E.D. van Breukelen, J. Rotteveel – ISIS Innovative Solutions In Space BV; ABSTRACT: This paper outlines the design and development of a VHF / UHF communications system for application in small satellites in LEO orbit. Based on the VHF / UHF transceiver as used in the Delfi-C3 nanosatellite, the transceiver presented in this paper features full duplex capability by providing a VHF Binary Phased Keying (BPSK) downlink up to 9600 bit/s and a UHF Frequency Shift Keying (FSK) uplink up to 9600bit/s. Lower datarates can be accommodated as well. It is usable over a wide frequency range, allowing both the amateur radio and commercial frequency bands to be used. The entire transceiver is housed on a single Printed Circuit Board of 90 x 96mm, making it possible to apply the transceiver as a low rate telemetry / telecommand transceiver in spacecraft ranging from nanosatellites to microsatellites. The transmitter section includes a class E nonlinear power amplifier of which the supply voltage is modulated with envelope information in order to allow for processing of non-constant envelope (shaped) BPSK modulation while maintaining both high power and spectral efficiency. This paper discusses the design and development of the VHF / UHF transceiver, the protocol used and the accompanying ground station software defined demodulation system. Special attention is given to the design methodology used.

8:45 a.m.Protection of Communication System from Solar Flares: K. Karthik, B.Shivram – Panimalar Engineering College; ABSTRACT: Solar flares are enormous explosions on the surface of the sun and they release energy of the order of billion megatons of TNT. This energy is in the form of electromagnetic radiations such as alpha, gamma, and ultraviolet rays. When exposed to high doses of radiation like 2-15 kilorad (Si), silicon integrated circuits in satellite communication systems fail to operate properly, thus affecting the performance of communication systems. Therefore, the major issue that needs to be addressed is the protection of integrated circuits and their survivability when they are exposed to various space environmental hazards including high doses of electrons, protons, solar flares and other cosmic radiations. In this paper, we present a survey of novel approaches whose effectiveness in protecting communication systems in space against solar flares has been demonstrated. In particular, we explore high Z materials used to form a radiation shielding that acts as a grit-blasted screen and low Z carbon nanotechnology used to protect against protons. We also make observations regarding a 3D layered coating for improved shielding, the use of commercially available substances, and additional ionizing radiation resistance to virtually sensitive electronic devices.

9:00 a.m.Inorganic Polymers for Space Applications: Brandon Cesul, Shankar Mall – Air Force Institute of Technology; Lawrence Matson – Air Force Research Laboratory; Heedong Lee – UES, Inc.; ABSTRACT: Spacecraft designers need to find innovative ways to reduce satellite mass. In this direction, a new technology is being developed which has the potential payoff in the difficult subsystem of imaging payloads. A class of inorganic polymers, called geopolymers, is being tested for their use as lightweight mirror materials. Two formulations, one for use as an adhesive and the other one for use as a structural material, are under development and are being space qualified as part of this overall effort. Geopolymers have the advantages of low initial coefficient of thermal expansion, easy preparation at room temperature and atmospheric conditions, castability, and adhesion to a number of common mirror coating materials. If successful, geopolymer based optics have the potential to improve the areal densities of traditional monolithic glass mirrors by a factor of 3 or more. This paper will detail the progress on our formulations of geopolymers for developing lightweight mirrors for space applications, and the status of the space qualification testing at this time, specifically the results of ASTM outgassing tests.

9:15 a.m. Advanced Methods for Structural Machining and Solar Cell Bonding Allowing High System Integration and Their Demonstration on a Pico–Satellite: Guillaume Roethlisberger, Fabien Jordan, Anthony Servonet, Maurice Borgeaud – Ecole Polytechnique Fédérale de Lausanne (EPFL) Space Center; Renato Krpoun, Herbert Shea – Microsystems for Space Technologies Laboratory/EPFL; ABSTRACT: The constraints on mass and size imposed on pico- and nanosatellites drive spacecraft designers to seek fabrication methods allowing a large degree of integration. From a configuration point of view, as sizes decrease the notion of subsystems vanishes, the structural interfaces become unique and need to be custom-made. This paper describes the integration concept of the SwissCube pico-satellite with special focus on the state-of-the art structural machining process. It also presents a new soldering technique for solar arrays. Both technologies are well suited for pico- to small- satellite applications and introduce flexibility in the design process. The first part will introduce the configuration of the SwissCube and present the advantages of wire electrical discharge machining (EDM) to manufacture the satellites primary structure. This technique, used for the SwissCube pico-satellite, has allowed the manufacture of a complex lightweight monoblock frame that serves as primary as well as secondary structure. The frame is one of the lightest in the CubeSat community while its rigidity is very high as shown by FEA and vibration tests. The second part will focus on a new bonding technique for solar arrays. So far the common technique for solar array bonding consisted of attaching solar cells with silicon or epoxy adhesives. In the frame of the SwissCube project, an innovative assembly approach of solar cells has been investigated. It consists of soldering solar cell on a printed circuit board panel with a process of brazing. Environmental tests have been successfully performed to evaluate the reliability of this process. Non destructives tests were also done to evaluate the quality of the solder pads.

9:30 a.m. Affordable Rad–Hard — An Impossible Dream?: David Alexander, Ken Hunt, Marc Owens, James Lyke Air Force Research Laboratory; ABSTRACT: Affordable electronics and radiation-hardened electronics have often been mutually exclusive terms. Recent activities at the Air Force Research Laboratory (AFRL) and other government organizations are focused on vastly improving the availability and affordability of high-performance rad-hard electronics to put them into the price range of small satellites. The projects include the development of an advanced FPGA, structured ASICs, 16-MbitS RAMs, and hardened versions of commercial devices such as a Texas Instrument 1394 chipset.

9:45 a.m.Initial Development of Embedded Low–Power Parallel Processing for On–Orbit Spacecraft Anomaly Management: Christopher Kitts, Paul Toledo, Mike Rasay Robotic Systems Laboratory/Santa Clara University; ABSTRACT: Maintaining the health of a spacecraft is a critical element of satellite operations, typically driving operations costs and often requiring standing armies of highly trained operations staff. An important aspect of this work is anomaly management (AM), which is the detection, diagnosis and resolution of anomalous conditions. Research in this area ranges from the development of robust reasoning techniques to the design of highly-performance flight processors able to implement these techniques on-orbit. Our recent work in this area focuses on the composition of advanced model-based reasoning (MBR) algorithms for AM that can be efficiently executed on a new generation of low-power, low-cost multi-core embedded processors. These processors provide a parallel-processing capability that can potentially revolutionize the performance of highly accurate but deliberative and computationally expensive MBR algorithms while still being suitable for space vehicle applications. In this paper, we will describe our latest theoretical and algorithmic contributions to MBR-based AM. We will discuss how our successfully demonstrated algorithms are being recast for parallel processing, and how these newly formed algorithms are being prototyped using new low-power multi-core embedded processors. Finally, we will discuss testbeds for this technology ranging from ground engineering units to simple student-based flight experiments.

10:00 a.m.Tunable Microstrip Bandpass Filters Based on Planner Split Ring Resonators: Alper Genc, Reyhan Baktur – Utah State University; ABSTRACT: A tunable bandpass microstrip filter based on varactor loaded Split Ring Resonators (SRRs) is presented. The filter is designed such a way that it has one transmission zero at the right hand side of the passband. Silicon tuning diode, of which capacitance is controlled by DC bias voltage, is used as the varactor element and it is placed between two concentric split rings of SRR to tune SRRs resonance frequency. Single module of the tuning filter is designed and simulated using Momentum 2006C software. The size of the SRR is chosen to have passband located at 2.8 GHz. And, it is fabricated on Rogers RO4003 high frequency laminate.

10:15 a.m.Advanced Antenna Design for a NASA Small Satellite Mission: Jason Lohn – Carnegie Mellon University; Derek Linden – JEM Engineering, LLC; Gregory Hornby – UC Santa Cruz; ABSTRACT: Current methods of designing and optimizing antennas by hand are time and labor intensive, limit complexity, and require significant expertise and experience. Evolutionary design techniques can overcome these limitations by searching the design space and automatically finding effective solutions that would not ordinarily be found. In recent years, evolutionary algorithms have shown great promise in finding practical solutions in large, complex design spaces. We present our work in using evolutionary algorithms to automatically design X-band antennas for a NASA small satellite mission called Space Technology 5 (ST5). The highest performing antennas produced were fabricated and tests showed they outperformed a traditionally-designed antenna produced by the antenna contractor for the mission. Subsequent changes to the spacecraft orbit resulted in a change in requirements for the spacecraft antenna. By adjusting our algorithm we were able to rapidly re-evolve a new set of requirements-compliant antennas in less than a month. One of these new antenna designs was built, tested and approved for deployment on the three ST5 spacecraft, which were successfully launched into space on March 22, 2006. Our three evolved antennas performed flawlessly during the three-month mission. These evolved antennas are the first computer-evolved antenna designs to be deployed for any application and are the first computer-evolved hardware in space.


		22nd Annual Conference on Small Satellites Technical Sessions Session XI: Advanced Technologies 2 Chair: John Monahan – RT Logic Thursday, August 14, 2008 8:30 a.m.A Miniaturized Nanosatellite VHF / UHF Communications System Wouter Jan Ubbels, A.R. Bonnema, E.D. van Breukelen, J. Rotteveel – ISIS Innovative Solutions In Space BV ABSTRACT: This paper outlines the design and development of a VHF / UHF communications system for application in small satellites in LEO orbit. Based on the VHF / UHF transceiver as used in the Delfi-C3 nanosatellite, the transceiver presented in this paper features full duplex capability by providing a VHF Binary Phased Keying (BPSK) downlink up to 9600 bit/s and a UHF Frequency Shift Keying (FSK) uplink up to 9600bit/s. Lower datarates can be accommodated as well. It is usable over a wide frequency range, allowing both the amateur radio and commercial frequency bands to be used. The entire transceiver is housed on a single Printed Circuit Board of 90 x 96mm, making it possible to apply the transceiver as a low rate telemetry / telecommand transceiver in spacecraft ranging from nanosatellites to microsatellites. The transmitter section includes a class E nonlinear power amplifier of which the supply voltage is modulated with envelope information in order to allow for processing of non-constant envelope (shaped) BPSK modulation while maintaining both high power and spectral efficiency. This paper discusses the design and development of the VHF / UHF transceiver, the protocol used and the accompanying ground station software defined demodulation system. Special attention is given to the design methodology used. 8:45 a.m.Protection of Communication System from Solar Flares K. Karthik, B.Shivram – Panimalar Engineering College ABSTRACT: Solar flares are enormous explosions on the surface of the sun and they release energy of the order of billion megatons of TNT. This energy is in the form of electromagnetic radiations such as alpha, gamma, and ultraviolet rays. When exposed to high doses of radiation like 2-15 kilorad (Si), silicon integrated circuits in satellite communication systems fail to operate properly, thus affecting the performance of communication systems. Therefore, the major issue that needs to be addressed is the protection of integrated circuits and their survivability when they are exposed to various space environmental hazards including high doses of electrons, protons, solar flares and other cosmic radiations. In this paper, we present a survey of novel approaches whose effectiveness in protecting communication systems in space against solar flares has been demonstrated. In particular, we explore high Z materials used to form a radiation shielding that acts as a grit-blasted screen and low Z carbon nanotechnology used to protect against protons. We also make observations regarding a 3D layered coating for improved shielding, the use of commercially available substances, and additional ionizing radiation resistance to virtually sensitive electronic devices. 9:00 a.m.Inorganic Polymers for Space Applications Brandon Cesul, Shankar Mall – Air Force Institute of Technology; Lawrence Matson – Air Force Research Laboratory; Heedong Lee – UES, Inc. ABSTRACT: Spacecraft designers need to find innovative ways to reduce satellite mass. In this direction, a new technology is being developed which has the potential payoff in the difficult subsystem of imaging payloads. A class of inorganic polymers, called geopolymers, is being tested for their use as lightweight mirror materials. Two formulations, one for use as an adhesive and the other one for use as a structural material, are under development and are being space qualified as part of this overall effort. Geopolymers have the advantages of low initial coefficient of thermal expansion, easy preparation at room temperature and atmospheric conditions, castability, and adhesion to a number of common mirror coating materials. If successful, geopolymer based optics have the potential to improve the areal densities of traditional monolithic glass mirrors by a factor of 3 or more. This paper will detail the progress on our formulations of geopolymers for developing lightweight mirrors for space applications, and the status of the space qualification testing at this time, specifically the results of ASTM outgassing tests. 9:15 a.m. Advanced Methods for Structural Machining and Solar Cell Bonding Allowing High System Integration and Their Demonstration on a Pico–Satellite Guillaume Roethlisberger, Fabien Jordan, Anthony Servonet, Maurice Borgeaud – Ecole Polytechnique Fédérale de Lausanne (EPFL) Space Center; Renato Krpoun, Herbert Shea – Microsystems for Space Technologies Laboratory/EPFL ABSTRACT: The constraints on mass and size imposed on pico- and nanosatellites drive spacecraft designers to seek fabrication methods allowing a large degree of integration. From a configuration point of view, as sizes decrease the notion of subsystems vanishes, the structural interfaces become unique and need to be custom-made. This paper describes the integration concept of the SwissCube pico-satellite with special focus on the state-of-the art structural machining process. It also presents a new soldering technique for solar arrays. Both technologies are well suited for pico- to small- satellite applications and introduce flexibility in the design process. The first part will introduce the configuration of the SwissCube and present the advantages of wire electrical discharge machining (EDM) to manufacture the satellites primary structure. This technique, used for the SwissCube pico-satellite, has allowed the manufacture of a complex lightweight monoblock frame that serves as primary as well as secondary structure. The frame is one of the lightest in the CubeSat community while its rigidity is very high as shown by FEA and vibration tests. The second part will focus on a new bonding technique for solar arrays. So far the common technique for solar array bonding consisted of attaching solar cells with silicon or epoxy adhesives. In the frame of the SwissCube project, an innovative assembly approach of solar cells has been investigated. It consists of soldering solar cell on a printed circuit board panel with a process of brazing. Environmental tests have been successfully performed to evaluate the reliability of this process. Non destructives tests were also done to evaluate the quality of the solder pads. 9:30 a.m. Affordable Rad–Hard — An Impossible Dream? David Alexander, Ken Hunt, Marc Owens, James Lyke Air Force Research Laboratory ABSTRACT: Affordable electronics and radiation-hardened electronics have often been mutually exclusive terms. Recent activities at the Air Force Research Laboratory (AFRL) and other government organizations are focused on vastly improving the availability and affordability of high-performance rad-hard electronics to put them into the price range of small satellites. The projects include the development of an advanced FPGA, structured ASICs, 16-MbitS RAMs, and hardened versions of commercial devices such as a Texas Instrument 1394 chipset. 9:45 a.m.Initial Development of Embedded Low–Power Parallel Processing for On–Orbit Spacecraft Anomaly Management Christopher Kitts, Paul Toledo, Mike Rasay Robotic Systems Laboratory/Santa Clara University ABSTRACT: Maintaining the health of a spacecraft is a critical element of satellite operations, typically driving operations costs and often requiring standing armies of highly trained operations staff. An important aspect of this work is anomaly management (AM), which is the detection, diagnosis and resolution of anomalous conditions. Research in this area ranges from the development of robust reasoning techniques to the design of highly-performance flight processors able to implement these techniques on-orbit. Our recent work in this area focuses on the composition of advanced model-based reasoning (MBR) algorithms for AM that can be efficiently executed on a new generation of low-power, low-cost multi-core embedded processors. These processors provide a parallel-processing capability that can potentially revolutionize the performance of highly accurate but deliberative and computationally expensive MBR algorithms while still being suitable for space vehicle applications. In this paper, we will describe our latest theoretical and algorithmic contributions to MBR-based AM. We will discuss how our successfully demonstrated algorithms are being recast for parallel processing, and how these newly formed algorithms are being prototyped using new low-power multi-core embedded processors. Finally, we will discuss testbeds for this technology ranging from ground engineering units to simple student-based flight experiments. 10:00 a.m.Tunable Microstrip Bandpass Filters Based on Planner Split Ring Resonators Alper Genc, Reyhan Baktur – Utah State University ABSTRACT: A tunable bandpass microstrip filter based on varactor loaded Split Ring Resonators (SRRs) is presented. The filter is designed such a way that it has one transmission zero at the right hand side of the passband. Silicon tuning diode, of which capacitance is controlled by DC bias voltage, is used as the varactor element and it is placed between two concentric split rings of SRR to tune SRRs resonance frequency. Single module of the tuning filter is designed and simulated using Momentum 2006C software. The size of the SRR is chosen to have passband located at 2.8 GHz. And, it is fabricated on Rogers RO4003 high frequency laminate. 10:15 a.m.Advanced Antenna Design for a NASA Small Satellite Mission Jason Lohn – Carnegie Mellon University; Derek Linden – JEM Engineering, LLC; Gregory Hornby – UC Santa Cruz ABSTRACT: Current methods of designing and optimizing antennas by hand are time and labor intensive, limit complexity, and require significant expertise and experience. Evolutionary design techniques can overcome these limitations by searching the design space and automatically finding effective solutions that would not ordinarily be found. In recent years, evolutionary algorithms have shown great promise in finding practical solutions in large, complex design spaces. We present our work in using evolutionary algorithms to automatically design X-band antennas for a NASA small satellite mission called Space Technology 5 (ST5). The highest performing antennas produced were fabricated and tests showed they outperformed a traditionally-designed antenna produced by the antenna contractor for the mission. Subsequent changes to the spacecraft orbit resulted in a change in requirements for the spacecraft antenna. By adjusting our algorithm we were able to rapidly re-evolve a new set of requirements-compliant antennas in less than a month. One of these new antenna designs was built, tested and approved for deployment on the three ST5 spacecraft, which were successfully launched into space on March 22, 2006. Our three evolved antennas performed flawlessly during the three-month mission. These evolved antennas are the first computer-evolved antenna designs to be deployed for any application and are the first computer-evolved hardware in space.