Session VI: Mission Payloads

Chair: Doug Sinclair – Sinclair Interplanetary

Tuesday, August 12, 2008

4:15 p.m. WiSAR: A New Solution for High–Performance, Smallsat–Based Synthetic Aperture Radar Missions: Peter Fox, Kenneth James, Alan Thompson – MacDonald Dettwiler and Associates, Ltd.; ABSTRACT: To date, high performance Synthetic Aperture Radar (SAR) satellites have typically featured massive power generation, storage and distribution subsystems, together with complex, heavy and rigid deployable SAR antenna structures. The result is an expensive, heavy satellite. MDA’s Wireless Synthetic Aperture Radar (WiSAR™) is a new SAR payload design that offers leading-edge performance in both X- and C-band at a significantly lower cost than the conventional state of the art. The key technology breakthrough is a modular, low mass phased array antenna technology that enables high performance multi-mode SAR imaging from a smallsat platform. 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 constrained feed design of traditional high performance SAR payloads. 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 describes the WiSAR payload technology in various configurations; a High Resolution X-Band Smallsat SAR, a Dual Aperture X-Band GMTI SAR, a High Performance C-Band SAR, and a C-Band Smallsat SAR. The results of a project to build, test and operate a fully functioning C-band prototype WiSAR phased array antenna are presented, along with current developments in X-Band.

4:30 p.m.Fully–Integrated Electronic System for a Plasma Impedance Probe: Magathi Jayaram, Mohamad El Hamoui, Swadesh Patra, Chris Winstead, Edmund Spence – Utah State University; ABSTRACT: This paper describes a single-chip electronic system for a Plasma Impedance Probe (PIP) currently being developed for microsatellite instrumentation. The chip integrates all of the major analog and mixed-signal components needed to perform swept-frequency impedance measurements. By integrating these components onto a single chip, the weight and volume of the PIP instrument are drastically reduced. Unlike previous PIP designs, the integrated PIP performs direct voltage/current sampling on the probes terminal. A Fast Fourier Transform (FFT) is performed by an off-chip FPGA to compute the impedance of the probe. By performing A-to-D conversion as early as possible in the signal flow chain, the design is made less sensitive to variability in analog components. By using an FFT operation, the instrument is made less sensitive to transient spikes that proved disruptive in previous PIP designs.

4:45 p.m. Microsatellites – A Light in the Darkness: Greg Finney, Denise Morell, Mark Fowler, Dane Phillips, Michael Gulley – Digital Fusion Solutions, Inc.; Randy Buff – US Army Space and Missile Defense Command; ABSTRACT: Digital Fusion Solutions, Inc. is currently developing a microsatellite payload for the US Army Space and Missile Defense Command that will serve as an exo-atmospheric infrared calibration source for a variety of ground and airborne infrared sensors. In addition to the primary mission, it will also serve to demonstrate a low-cost satellite development approach. This mission is well-suited to microsatellites because it requires low average power, limited pointing control, and modest pointing knowledge. Challenges for this active infrared payload include achieving the required radiometric accuracy, power handling (high peak power at low duty cycle), and ensuring coverage of airborne sensors. Payload design, performance testing, and initial environmental test plans will be discussed.

5:00 p.m. A Miniature UV Imaging Spectrometer for Remote Sensing of the Atmosphere: Juan Fernandez, Craig Underwood – Surrey Space Centre; ABSTRACT: A new miniature ultraviolet (UV)-band spectral imager is proposed with the objective of monitoring important atmospheric constituents: sulphur dioxide, ozone and aerosols. Ideally the instrument will operate in a micro/nano-satellite constellation in order to provide the rapid response and dynamic requirements of a very demanding application such as volcano monitoring based on one of the most important gases they emit: sulphur dioxide (SO2).

5:15 p.m. Possible Orbit Scenarios for an InSAR Formation Flying Microsatellite Mission: Erica Peterson, Robert Zee – Space Flight Laboratory/University of Toronto; Georgia Fotopoulos – University of Toronto; ABSTRACT: Multistatic interferometric synthetic aperture radar (InSAR) is a promising future payload for a small satellite constellation, providing a low-cost means of augmenting proven “large” SAR mission technology. The Space Flight Laboratory at the University of Toronto Institute for Aerospace Studies is currently designing CanX-4 and CanX-5, a pair of formation-flying nanosatellites slated for launch in 2009. Once formation flight has been demonstrated, a future multistatic InSAR formation-flying constellation can exploit sub-centimeter inter-satellite baseline knowledge for interferometric measurements, which can be used for a myriad of applications including surface deformation, digital terrain modeling, and moving target detection. This study evaluates two commonly proposed InSAR constellation configurations, namely the Cartwheel and the Cross-Track Pendulum, and considers two “large” (~kilowatt) SAR transmitters (C- and X-band) and one microsatellite transmitter (X-band, 150W). Each case is evaluated and assessed with respect to the available interferometric baselines and ground coverage. The microsatellite X-band transmitter is found to be technically feasible, although the lower available transmitter power limits the operating range. The selected transmit band determines the maximum allowable cross-track baseline between receiver satellites in the constellation. Additionally, the Cartwheel and Cross-Track Pendulum configurations offer different available baselines and ground coverage patterns, namely, the Cartwheel eliminates the near-zero cross-track baseline component that contributes to DEM height errors but adds a coupled along-track baseline, while the Cross-Track Pendulum offers the advantage of independent cross-track and along-track baseline components. Ultimately, the primary application for the InSAR data will dictate the transmit band used, the desired baselines, and the receiver constellation configuration.

5:30 p.m. High Performance Optical Imaging Payloads for Smallsat Missions: George Tyc, Wade Larson – MacDonald Dettwiler and Associates, Ltd.; Tim Butlin – Orbital Optics Ltd./Rutherford Appleton Laboratory; Nick Waltham, Nigel Morris, Ian Tosh – Rutherford Appleton Laboratory; ABSTRACT: This paper describes what we believe is a disruptive technology solution for smallsat optical imaging missions, that combines a new line of cameras that provide very high quality, high resolution imaging, with a low power Payload Controller, Processor and Memory Unit (PCPMU) that provides multi-terrabit on-board data storage and high speed data output at a uniquely low price point. Working together with the Rutherford Appleton Laboratory in the UK, MDA is developing the RALCam family of high resolution multispectral cameras, capable of up to 0.5 m GSD imaging from a 500 km altitude. Two related camera systems in the product family are described, one that provides 1.0 m GSD and the other that provides 0.5 m GSD. Key performance specifications for both cameras are given. Hardware testing results are also summarized. MDA are incorporating these cameras and payload electronics into a highly price competitive mission level solution that includes a spacecraft designed and optimized specifically for the RALCam high resolution cameras and a full ground segment that includes the satellite control & tasking, uplink and downlinks, and image processing and archiving which produces very high quality image & information products. MDA’s optical spacecraft design that incorporates the RALCam high resolution cameras is also described and key performance parameters are given. Finally, concluding remarks are provided that summarize the key technology and price point enablers. The first system could be launched as early as 2010 and we expect this will change the economics of operational class high resolution optical remote sensing.

Alternate Comparison of Results Between the Miniature FASat-Bravo Ozone Mapping Detector (OMAD) and NASA’s Total Ozone Mapping Spectrometer (TOMS): Juan Fernandez, Craig Underwood – Surrey Space Centre; ABSTRACT: The Ozone Layer Monitoring Experiment (OLME) on board the FASat-Bravo microsatellite launched in July 1992 observed backscattered UV to retrieve atmospheric ozone using two instruments: the Ozone Ultraviolet Backscatter Imager (OUBI) and the Ozone Mapping Detector (OMAD). Initial results from this experiment have shown good qualitative agreement with data from NASA’s TOMS instrument [1]. More recent studies of OMAD data have found quantitative agreement in their radiances and even indicated detection of a volcanic eruption plume from the Nyamuragira volcano [2].

Alternate ORS Payload Technologies Initiative: Joe Gherlone Jr., Christopher Huffine, Michael Hurley – Naval Research Laboratory; Thomas Doyne – Secretary of Defense / Networks and Information Integration; ABSTRACT: In 2006, the Office of Force Transformation, now organized under the Director of Defense Research & Engineering, began an initiative for the development of payload and bus technologies for Operationally Responsive Space (ORS). The Naval Research Laboratory (NRL) Naval Center for Space Technology (NCST) was requested to manage the initiative with the objectives and attributes of 1) addressing ORS-unique capabilities, 2) directed at Combatant Commander (COCOM) operational concepts and needs, 3) with primary transition to Joint TACSAT experimentation or ORS payload acquisition, and 4) to expand the ORS industrial base. NRL developed and followed a fully Joint process for solicitation, Industry Day, selection, and execution of 20 projects from a field of 75 proposals. Each potential ORS payload technology was advanced in maturity, with several already transitioning to follow-on development programs or transitioning directly into flight projects. This initiative and similar efforts are critical to developing ORS and the use of military small satellites to their full potential. Recommendations for future processes and a way ahead are offered.


		22nd Annual Conference on Small Satellites Technical Sessions Session VI: Mission Payloads Chair: Doug Sinclair – Sinclair Interplanetary Tuesday, August 12, 2008 4:15 p.m. WiSAR: A New Solution for High–Performance, Smallsat–Based Synthetic Aperture Radar Missions Peter Fox, Kenneth James, Alan Thompson – MacDonald Dettwiler and Associates, Ltd. ABSTRACT: To date, high performance Synthetic Aperture Radar (SAR) satellites have typically featured massive power generation, storage and distribution subsystems, together with complex, heavy and rigid deployable SAR antenna structures. The result is an expensive, heavy satellite. MDA’s Wireless Synthetic Aperture Radar (WiSAR™) is a new SAR payload design that offers leading-edge performance in both X- and C-band at a significantly lower cost than the conventional state of the art. The key technology breakthrough is a modular, low mass phased array antenna technology that enables high performance multi-mode SAR imaging from a smallsat platform. 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 constrained feed design of traditional high performance SAR payloads. 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 describes the WiSAR payload technology in various configurations; a High Resolution X-Band Smallsat SAR, a Dual Aperture X-Band GMTI SAR, a High Performance C-Band SAR, and a C-Band Smallsat SAR. The results of a project to build, test and operate a fully functioning C-band prototype WiSAR phased array antenna are presented, along with current developments in X-Band. 4:30 p.m.Fully–Integrated Electronic System for a Plasma Impedance Probe Magathi Jayaram, Mohamad El Hamoui, Swadesh Patra, Chris Winstead, Edmund Spence – Utah State University ABSTRACT: This paper describes a single-chip electronic system for a Plasma Impedance Probe (PIP) currently being developed for microsatellite instrumentation. The chip integrates all of the major analog and mixed-signal components needed to perform swept-frequency impedance measurements. By integrating these components onto a single chip, the weight and volume of the PIP instrument are drastically reduced. Unlike previous PIP designs, the integrated PIP performs direct voltage/current sampling on the probes terminal. A Fast Fourier Transform (FFT) is performed by an off-chip FPGA to compute the impedance of the probe. By performing A-to-D conversion as early as possible in the signal flow chain, the design is made less sensitive to variability in analog components. By using an FFT operation, the instrument is made less sensitive to transient spikes that proved disruptive in previous PIP designs. 4:45 p.m. Microsatellites – A Light in the Darkness Greg Finney, Denise Morell, Mark Fowler, Dane Phillips, Michael Gulley – Digital Fusion Solutions, Inc.; Randy Buff – US Army Space and Missile Defense Command ABSTRACT: Digital Fusion Solutions, Inc. is currently developing a microsatellite payload for the US Army Space and Missile Defense Command that will serve as an exo-atmospheric infrared calibration source for a variety of ground and airborne infrared sensors. In addition to the primary mission, it will also serve to demonstrate a low-cost satellite development approach. This mission is well-suited to microsatellites because it requires low average power, limited pointing control, and modest pointing knowledge. Challenges for this active infrared payload include achieving the required radiometric accuracy, power handling (high peak power at low duty cycle), and ensuring coverage of airborne sensors. Payload design, performance testing, and initial environmental test plans will be discussed. 5:00 p.m. A Miniature UV Imaging Spectrometer for Remote Sensing of the Atmosphere Juan Fernandez, Craig Underwood – Surrey Space Centre ABSTRACT: A new miniature ultraviolet (UV)-band spectral imager is proposed with the objective of monitoring important atmospheric constituents: sulphur dioxide, ozone and aerosols. Ideally the instrument will operate in a micro/nano-satellite constellation in order to provide the rapid response and dynamic requirements of a very demanding application such as volcano monitoring based on one of the most important gases they emit: sulphur dioxide (SO2). 5:15 p.m. Possible Orbit Scenarios for an InSAR Formation Flying Microsatellite Mission Erica Peterson, Robert Zee – Space Flight Laboratory/University of Toronto; Georgia Fotopoulos – University of Toronto ABSTRACT: Multistatic interferometric synthetic aperture radar (InSAR) is a promising future payload for a small satellite constellation, providing a low-cost means of augmenting proven “large” SAR mission technology. The Space Flight Laboratory at the University of Toronto Institute for Aerospace Studies is currently designing CanX-4 and CanX-5, a pair of formation-flying nanosatellites slated for launch in 2009. Once formation flight has been demonstrated, a future multistatic InSAR formation-flying constellation can exploit sub-centimeter inter-satellite baseline knowledge for interferometric measurements, which can be used for a myriad of applications including surface deformation, digital terrain modeling, and moving target detection. This study evaluates two commonly proposed InSAR constellation configurations, namely the Cartwheel and the Cross-Track Pendulum, and considers two “large” (~kilowatt) SAR transmitters (C- and X-band) and one microsatellite transmitter (X-band, 150W). Each case is evaluated and assessed with respect to the available interferometric baselines and ground coverage. The microsatellite X-band transmitter is found to be technically feasible, although the lower available transmitter power limits the operating range. The selected transmit band determines the maximum allowable cross-track baseline between receiver satellites in the constellation. Additionally, the Cartwheel and Cross-Track Pendulum configurations offer different available baselines and ground coverage patterns, namely, the Cartwheel eliminates the near-zero cross-track baseline component that contributes to DEM height errors but adds a coupled along-track baseline, while the Cross-Track Pendulum offers the advantage of independent cross-track and along-track baseline components. Ultimately, the primary application for the InSAR data will dictate the transmit band used, the desired baselines, and the receiver constellation configuration. 5:30 p.m. High Performance Optical Imaging Payloads for Smallsat Missions George Tyc, Wade Larson – MacDonald Dettwiler and Associates, Ltd.; Tim Butlin – Orbital Optics Ltd./Rutherford Appleton Laboratory; Nick Waltham, Nigel Morris, Ian Tosh – Rutherford Appleton Laboratory ABSTRACT: This paper describes what we believe is a disruptive technology solution for smallsat optical imaging missions, that combines a new line of cameras that provide very high quality, high resolution imaging, with a low power Payload Controller, Processor and Memory Unit (PCPMU) that provides multi-terrabit on-board data storage and high speed data output at a uniquely low price point. Working together with the Rutherford Appleton Laboratory in the UK, MDA is developing the RALCam family of high resolution multispectral cameras, capable of up to 0.5 m GSD imaging from a 500 km altitude. Two related camera systems in the product family are described, one that provides 1.0 m GSD and the other that provides 0.5 m GSD. Key performance specifications for both cameras are given. Hardware testing results are also summarized. MDA are incorporating these cameras and payload electronics into a highly price competitive mission level solution that includes a spacecraft designed and optimized specifically for the RALCam high resolution cameras and a full ground segment that includes the satellite control & tasking, uplink and downlinks, and image processing and archiving which produces very high quality image & information products. MDA’s optical spacecraft design that incorporates the RALCam high resolution cameras is also described and key performance parameters are given. Finally, concluding remarks are provided that summarize the key technology and price point enablers. The first system could be launched as early as 2010 and we expect this will change the economics of operational class high resolution optical remote sensing. Alternate Comparison of Results Between the Miniature FASat-Bravo Ozone Mapping Detector (OMAD) and NASA’s Total Ozone Mapping Spectrometer (TOMS) Juan Fernandez, Craig Underwood – Surrey Space Centre ABSTRACT: The Ozone Layer Monitoring Experiment (OLME) on board the FASat-Bravo microsatellite launched in July 1992 observed backscattered UV to retrieve atmospheric ozone using two instruments: the Ozone Ultraviolet Backscatter Imager (OUBI) and the Ozone Mapping Detector (OMAD). Initial results from this experiment have shown good qualitative agreement with data from NASA’s TOMS instrument [1]. More recent studies of OMAD data have found quantitative agreement in their radiances and even indicated detection of a volcanic eruption plume from the Nyamuragira volcano [2]. Alternate ORS Payload Technologies Initiative Joe Gherlone Jr., Christopher Huffine, Michael Hurley – Naval Research Laboratory; Thomas Doyne – Secretary of Defense / Networks and Information Integration ABSTRACT: In 2006, the Office of Force Transformation, now organized under the Director of Defense Research & Engineering, began an initiative for the development of payload and bus technologies for Operationally Responsive Space (ORS). The Naval Research Laboratory (NRL) Naval Center for Space Technology (NCST) was requested to manage the initiative with the objectives and attributes of 1) addressing ORS-unique capabilities, 2) directed at Combatant Commander (COCOM) operational concepts and needs, 3) with primary transition to Joint TACSAT experimentation or ORS payload acquisition, and 4) to expand the ORS industrial base. NRL developed and followed a fully Joint process for solicitation, Industry Day, selection, and execution of 20 projects from a field of 75 proposals. Each potential ORS payload technology was advanced in maturity, with several already transitioning to follow-on development programs or transitioning directly into flight projects. This initiative and similar efforts are critical to developing ORS and the use of military small satellites to their full potential. Recommendations for future processes and a way ahead are offered.