Session X: Thinking Outside the Box

Chair: John Hines – NASA Ames Research Center; Steve Buckley – Air Force Research Laboratory

Wednesday, August 13, 2008

3:45 p.m. NanoSail–D: The First Flight Demonstration of Solar Sails for NanoSatellites: Mark Whorton, Andy Heaton, Robin Pinson – NASA Marshall Space Flight Center; Greg Laue – ManTech SRS Technologies; Charles Adams – Gray Research, Inc.; ABSTRACT: The “NanoSail–D” mission is currently scheduled for launch onboard a Falcon Launch Vehicle in the late June 2008 timeframe. The NanoSail–D, a CubeSat–class satellite, will consist of a sail subsystem stowed in a Cubesat 2U volume integrated with a CubeSat 1U volume bus provided by the NASA Ames Research Center (ARC). Shortly after deployment of the NanoSail–D from a Poly Picosatellite Orbital Deployer (P–POD) ejection system, the solar sail will deploy and mission operations will commence. This demonstration flight has two primary mission objectives: 1) to successfully stow and deploy the sail and 2) to demonstrate de–orbit functionality. Given a near–term opportunity for launch, the project was met with the challenge of delivering the flight hardware in approximately six months, which required a significant constraint on flight system functionality. As a consequence, passive attitude stabilization will be achieved using permanent magnets to de–tumble and orient the body with the magnetic field lines and then rely on atmospheric drag to passively stabilize the sailcraft in an essentially maximum drag attitude. This paper will present an introduction to solar sail propulsion systems, overview the NanoSail–D spacecraft, describe the performance analysis for the passive attitude stabilization, and present a prediction of flight data results from the mission.

4:00 p.m.Large Constellation Development Using Small Satellites: Bryan Bingham, Quinn Young – Space Dynamics Laboratory; Stephen Whitmore – Utah State University; ABSTRACT: Many natural phenomena of interest occur on a global scale. Accurately measuring and studying these phenomena require creating a network of globally spaced sensors a constellation of satellites allows for simultaneous global measurements, but has been traditionally viewed as cost prohibitive. Recent developments in small satellite technology have made it possible to create a global constellation while maintaining the cost at reasonable level. This paper describes the practical development of a global constellation of 90 pico-satellites that will be used for distributed ionospheric diagnostics. The constellation is created using one standard low-cost launch vehicle with an adept final insertion stage. The satellite design is based on the readily available and well-established pico-satellite technology developed by the Cubesat community. A single science sensor is highly integerated with the pico-satellite bus design. This “sensor-sat” design approach minimizes volume and mass, allowing for 90 sensor-sats to be launched and deployed from a single launch vehicle. The novel constellation design presented in this paper clearly identifies the platform upon which the next generation of space science and space weather needs can be effectively met using current small satellite technology.

4:15 p.m.MISC™—A Novel Approach to Low–Cost Imaging Satellites: Andrew Kalman, Adam Reif – Pumpkin, Inc.; Dan Berkenstock, Julian Mann, James Cutler – Stanford University; ABSTRACT: By severely limiting satellite size and weight, the popular CubeSat nanosatellite standard realizes noticeable cost savings over traditional satellites in the areas of design, manufacture, launch and operations. To date, there has been limited commercial utilization of CubeSat systems due to the widespread perception in industry that a 10 cm x 10 cm x 30 cm form factor is too constrained for payloads in support of useful missions. In this paper, we argue against this perception by presenting MISC™, a 3U CubeSat capable of providing 7.5 m GSD multispectral imagery from a circular orbit of 540 km. Over an anticipated operational lifetime of 18 months, each MISC will be able to image over 75 million km2, equivalent to approximately half the Earths landmass. MISCs novel design combines a robust miniature imager module payload with an existing CubeSat Kit-based bus and a distributed ground station architecture. With anticipated order-of-magnitude cost savings when compared to current commercial offerings, MISC's lifetime system cost should represent an extremely attractive proposition to consumers of satellite imagery that wish to own and operate their own assets. MISC satellites will be available for commercial purchase in mid-2009.

4:30 p.m.Tinyscope — The Feasibility of a 3–Axis Stabilized Earth Imaging Cubesat from LEO

Allen Blocker, Chance Litton, Jason Hall, Marcello Romano – Naval Postgraduate School

ABSTRACT: The idea of a nano-sat for tactical imaging applications from LEO is explored. On the battlefield, not every tactical situation requires something as high-tech as an FA-18 dropping a GPS-guided weapon within a couple of meters of the target to get the desired results - sometimes a grenade or a mortar will do the trick. In the same way, a nano-sat imaging from LEO may be a better solution than a national imaging asset for some applications. These spacecraft may be used as short-term low-cost independent elements, for instance; or perhaps in support of traditional large imaging space systems as free-flying targeting telescopes. They may also be deployed as elements of a LEO constellation or cluster (think swarm), which would allow for quick re-targeting opportunities over a large portion of the Earth.

Tactical Imaging Nano-sat Yielding Small-Cost Operations and Persistent Earth-coverage (TINYSCOPE) is a preliminary investigation using analytical modeling and laboratory experimentation to determine the potential performance and the feasibility of using a 5-U CubeSat as an imager. Emphasis is placed on three-axis attitude stabilization and slewing (for target acquisition and tracking) and performance of various optics hardware configurations. Numerical simulations will be conducted to support the study, in particular on spacecraft dynamics and control.

4:45 p.m.Integrating Lithium Polymer Charging and Peak Power Tracking on a CubeSat Class Satellite: Dan Kaste, Will Holmes, Dan Brinks, Joel Gegner, Jim Moore, Hugh Whit – Taylor University; ABSTRACT: Every satellite must regulate incoming power from solar cells, charge batteries and regulate satellite power to maintain satellite health. The power system should be as light, small, and efficient as possible to allow a maximum of resources to satellite systems while minimizing complexity, and meeting CubeSat mechanical and thermal requirements. This paper describes a modular power system, which integrates peak power tracking, battery charging, and power regulation. In addition, it describes the entire power design of a CubeSat power system. This system includes the modular power system described above together with solar cells, and lithium polymer batteries. Due to a limited budget and limited efficiency of solar cells, there is very little power to supply the satellite. Therefore, the power system achieves good efficiency and low mass/volume by implementing a bang-bang peak power tracking system with integrated battery charging. This system will use a PWM buck-boost converter to control the current drawn from the solar cells as well as regulate the charging of the lithium polymer batteries. A micro-controller tracks the feedback from the peak power / charging system and adjusts the regulator accordingly. In addition to the peak power tracker, a power management scheme insures longer operating periods and a reliable downlink transmission. This design results in a highly integrated power system.

5:00 p.m. A Low–Power Dual–Processor Computing System for Advanced NanoSatellite Missions: Nathaniel Colson, Paul Moonjelly, David Filmer – Purdue University; ABSTRACT: This paper discusses the design of the Flight Computing System for PurdueSat—a 2–U CubeSat being developed at the School of Aeronautics & Astronautics, Purdue University. The satellite employs sophisticated attitude determination algorithms and autonomous attitude control using magnetorquers as the only actuators, which requires substantial computation at runtime. To meet these computational demands, we have developed a unique dual–processor computing system that is capable of handling computationally intense algorithms, while still maintaining ultra–low levels of power consumption. These characteristics are achieved by the optimal combination of two highly energy–efficient computers—a Digital Signal Processor geared towards large matrix multiplications, and an ultra-low power “host computer” that can duty–cycle its counterpart and perform all the housekeeping functions onboard the satellite.

AlternateFlight Results of the Delfi–C3 Satellite Mission: Wouter Jan Ubbels – ISIS Innovative Solutions In Space BV; C.J.M. Verhoeven, R. J. Hamann, E. Gill, J. Bouwmeester – Delft University of Technology; ABSTRACT: Delfi-C3 is a 3-unit CubeSat nanosatellite developed at Delft University of Technology by students and staff from the faculty of Aerospace Engineering and the faculty of Electrical Engineering, Mathematics and Computer Science with engineering support from ISIS—Innovative Solutions In Space BV. The project started in December 2004 and the satellite was launched on April 28th 2008 with a Polar Satellite Launch Vehicle from India. The prime mission objective of Delfi-C3 is to act as a technology test bed for two payloads: Thin Film Solar Cells, as developed by the company Dutch Space, and an Autonomous Wireless Sun Sensor developed by the Dutch research institute TNO, demonstrating on-board wireless sensor capability. The satellite bus implements a number of novel design concepts. One of which is the fact that the satellite does not incorporate a battery for energy storage since neither of the two payloads require operations in eclipse. In this paper, some preliminary flight results of Delfi-C3 are discussed with an emphasis on the overall in-orbit performance of the satellite itself. Furthermore, results characterizing the payload and its operations are presented. Finally, the status and summary of operational results of the distributed ground segment is provided. Delfi-C3 is the first of a series of nanosatellites from Delft University of Technology, designed for technology demonstration, as part of the MISAT research program. An outlook is given to a follow-up mission, which is currently in its conceptual design phase.

Alternate Bridging the Gap: Collaboration using Nanosat and CubeSat Platforms through the Texas 2–STEP (2 Satellite Targeting Experimental Platform) Mission: Cinnamon Wright, Dax Garner, Jessica Williams, Henri Kjellberg, E. Glenn Lightsey – University of Texas at Austin; ABSTRACT: The Texas 2-STEP (2-Satellite Targeting Experimental Platform) mission is the University of Texas at Austin's (UT-Austin) entry into the University Nanosat-5 (UNP-5) competition, a program sponsored by the Air Force Research Laboratory (AFRL), NASA and the American Institute of Aeronautics and Astronautics. The 2-STEP mission is to perform an autonomous rendezvous and formation flight demonstration using an innovative and inexpensive GN&C system. Two vehicles will be launched in a joined configuration but will perform a separation maneuver on-orbit to drift apart to a distance of 3 kilometers. When commanded, the larger, actively controlled Chaser nanosatellite will autonomously maneuver back to within 100 meters of the smaller, passively controlled Target. The Target vehicle is designed based on the CubeSat platform, a design solution that merges the Nanosat and CubeSat programs in a unique collaboration that has not been previously demonstrated. A standard CubeSat platform has been designed using commercial hardware which can be adapted for a 1U (1-Unit), 2U or 3U CubeSat mission. Use of the CubeSat standard is a responsive space solution that incorporates a modular vehicle design for use in multiple university missions. Adoption of this standard also promotes collaboration between Satellite Design Laboratory programs at UT-Austin. This paper will review the Texas 2-STEP mission and highlight how the Target vehicle is bridging a gap between the Nanosat and CubeSat communities. Elements of vehicle design as well as Chaser-Target team cooperation will also be covered.


		22nd Annual Conference on Small Satellites Technical Sessions Session X: Thinking Outside the Box Chair: John Hines – NASA Ames Research Center; Steve Buckley – Air Force Research Laboratory Wednesday, August 13, 2008 3:45 p.m. NanoSail–D: The First Flight Demonstration of Solar Sails for NanoSatellites Mark Whorton, Andy Heaton, Robin Pinson – NASA Marshall Space Flight Center; Greg Laue – ManTech SRS Technologies; Charles Adams – Gray Research, Inc. ABSTRACT: The “NanoSail–D” mission is currently scheduled for launch onboard a Falcon Launch Vehicle in the late June 2008 timeframe. The NanoSail–D, a CubeSat–class satellite, will consist of a sail subsystem stowed in a Cubesat 2U volume integrated with a CubeSat 1U volume bus provided by the NASA Ames Research Center (ARC). Shortly after deployment of the NanoSail–D from a Poly Picosatellite Orbital Deployer (P–POD) ejection system, the solar sail will deploy and mission operations will commence. This demonstration flight has two primary mission objectives: 1) to successfully stow and deploy the sail and 2) to demonstrate de–orbit functionality. Given a near–term opportunity for launch, the project was met with the challenge of delivering the flight hardware in approximately six months, which required a significant constraint on flight system functionality. As a consequence, passive attitude stabilization will be achieved using permanent magnets to de–tumble and orient the body with the magnetic field lines and then rely on atmospheric drag to passively stabilize the sailcraft in an essentially maximum drag attitude. This paper will present an introduction to solar sail propulsion systems, overview the NanoSail–D spacecraft, describe the performance analysis for the passive attitude stabilization, and present a prediction of flight data results from the mission. 4:00 p.m.Large Constellation Development Using Small Satellites Bryan Bingham, Quinn Young – Space Dynamics Laboratory; Stephen Whitmore – Utah State University ABSTRACT: Many natural phenomena of interest occur on a global scale. Accurately measuring and studying these phenomena require creating a network of globally spaced sensors a constellation of satellites allows for simultaneous global measurements, but has been traditionally viewed as cost prohibitive. Recent developments in small satellite technology have made it possible to create a global constellation while maintaining the cost at reasonable level. This paper describes the practical development of a global constellation of 90 pico-satellites that will be used for distributed ionospheric diagnostics. The constellation is created using one standard low-cost launch vehicle with an adept final insertion stage. The satellite design is based on the readily available and well-established pico-satellite technology developed by the Cubesat community. A single science sensor is highly integerated with the pico-satellite bus design. This “sensor-sat” design approach minimizes volume and mass, allowing for 90 sensor-sats to be launched and deployed from a single launch vehicle. The novel constellation design presented in this paper clearly identifies the platform upon which the next generation of space science and space weather needs can be effectively met using current small satellite technology. 4:15 p.m.MISC™—A Novel Approach to Low–Cost Imaging Satellites Andrew Kalman, Adam Reif – Pumpkin, Inc.; Dan Berkenstock, Julian Mann, James Cutler – Stanford University ABSTRACT: By severely limiting satellite size and weight, the popular CubeSat nanosatellite standard realizes noticeable cost savings over traditional satellites in the areas of design, manufacture, launch and operations. To date, there has been limited commercial utilization of CubeSat systems due to the widespread perception in industry that a 10 cm x 10 cm x 30 cm form factor is too constrained for payloads in support of useful missions. In this paper, we argue against this perception by presenting MISC™, a 3U CubeSat capable of providing 7.5 m GSD multispectral imagery from a circular orbit of 540 km. Over an anticipated operational lifetime of 18 months, each MISC will be able to image over 75 million km2, equivalent to approximately half the Earths landmass. MISCs novel design combines a robust miniature imager module payload with an existing CubeSat Kit-based bus and a distributed ground station architecture. With anticipated order-of-magnitude cost savings when compared to current commercial offerings, MISC's lifetime system cost should represent an extremely attractive proposition to consumers of satellite imagery that wish to own and operate their own assets. MISC satellites will be available for commercial purchase in mid-2009. 4:30 p.m.Tinyscope — The Feasibility of a 3–Axis Stabilized Earth Imaging Cubesat from LEO Allen Blocker, Chance Litton, Jason Hall, Marcello Romano – Naval Postgraduate School ABSTRACT: The idea of a nano-sat for tactical imaging applications from LEO is explored. On the battlefield, not every tactical situation requires something as high-tech as an FA-18 dropping a GPS-guided weapon within a couple of meters of the target to get the desired results - sometimes a grenade or a mortar will do the trick. In the same way, a nano-sat imaging from LEO may be a better solution than a national imaging asset for some applications. These spacecraft may be used as short-term low-cost independent elements, for instance; or perhaps in support of traditional large imaging space systems as free-flying targeting telescopes. They may also be deployed as elements of a LEO constellation or cluster (think swarm), which would allow for quick re-targeting opportunities over a large portion of the Earth. Tactical Imaging Nano-sat Yielding Small-Cost Operations and Persistent Earth-coverage (TINYSCOPE) is a preliminary investigation using analytical modeling and laboratory experimentation to determine the potential performance and the feasibility of using a 5-U CubeSat as an imager. Emphasis is placed on three-axis attitude stabilization and slewing (for target acquisition and tracking) and performance of various optics hardware configurations. Numerical simulations will be conducted to support the study, in particular on spacecraft dynamics and control. 4:45 p.m.Integrating Lithium Polymer Charging and Peak Power Tracking on a CubeSat Class Satellite Dan Kaste, Will Holmes, Dan Brinks, Joel Gegner, Jim Moore, Hugh Whit – Taylor University ABSTRACT: Every satellite must regulate incoming power from solar cells, charge batteries and regulate satellite power to maintain satellite health. The power system should be as light, small, and efficient as possible to allow a maximum of resources to satellite systems while minimizing complexity, and meeting CubeSat mechanical and thermal requirements. This paper describes a modular power system, which integrates peak power tracking, battery charging, and power regulation. In addition, it describes the entire power design of a CubeSat power system. This system includes the modular power system described above together with solar cells, and lithium polymer batteries. Due to a limited budget and limited efficiency of solar cells, there is very little power to supply the satellite. Therefore, the power system achieves good efficiency and low mass/volume by implementing a bang-bang peak power tracking system with integrated battery charging. This system will use a PWM buck-boost converter to control the current drawn from the solar cells as well as regulate the charging of the lithium polymer batteries. A micro-controller tracks the feedback from the peak power / charging system and adjusts the regulator accordingly. In addition to the peak power tracker, a power management scheme insures longer operating periods and a reliable downlink transmission. This design results in a highly integrated power system. 5:00 p.m. A Low–Power Dual–Processor Computing System for Advanced NanoSatellite Missions Nathaniel Colson, Paul Moonjelly, David Filmer – Purdue University ABSTRACT: This paper discusses the design of the Flight Computing System for PurdueSat—a 2–U CubeSat being developed at the School of Aeronautics & Astronautics, Purdue University. The satellite employs sophisticated attitude determination algorithms and autonomous attitude control using magnetorquers as the only actuators, which requires substantial computation at runtime. To meet these computational demands, we have developed a unique dual–processor computing system that is capable of handling computationally intense algorithms, while still maintaining ultra–low levels of power consumption. These characteristics are achieved by the optimal combination of two highly energy–efficient computers—a Digital Signal Processor geared towards large matrix multiplications, and an ultra-low power “host computer” that can duty–cycle its counterpart and perform all the housekeeping functions onboard the satellite. AlternateFlight Results of the Delfi–C3 Satellite Mission Wouter Jan Ubbels – ISIS Innovative Solutions In Space BV; C.J.M. Verhoeven, R. J. Hamann, E. Gill, J. Bouwmeester – Delft University of Technology ABSTRACT: Delfi-C3 is a 3-unit CubeSat nanosatellite developed at Delft University of Technology by students and staff from the faculty of Aerospace Engineering and the faculty of Electrical Engineering, Mathematics and Computer Science with engineering support from ISIS—Innovative Solutions In Space BV. The project started in December 2004 and the satellite was launched on April 28th 2008 with a Polar Satellite Launch Vehicle from India. The prime mission objective of Delfi-C3 is to act as a technology test bed for two payloads: Thin Film Solar Cells, as developed by the company Dutch Space, and an Autonomous Wireless Sun Sensor developed by the Dutch research institute TNO, demonstrating on-board wireless sensor capability. The satellite bus implements a number of novel design concepts. One of which is the fact that the satellite does not incorporate a battery for energy storage since neither of the two payloads require operations in eclipse. In this paper, some preliminary flight results of Delfi-C3 are discussed with an emphasis on the overall in-orbit performance of the satellite itself. Furthermore, results characterizing the payload and its operations are presented. Finally, the status and summary of operational results of the distributed ground segment is provided. Delfi-C3 is the first of a series of nanosatellites from Delft University of Technology, designed for technology demonstration, as part of the MISAT research program. An outlook is given to a follow-up mission, which is currently in its conceptual design phase. Alternate Bridging the Gap: Collaboration using Nanosat and CubeSat Platforms through the Texas 2–STEP (2 Satellite Targeting Experimental Platform) Mission Cinnamon Wright, Dax Garner, Jessica Williams, Henri Kjellberg, E. Glenn Lightsey – University of Texas at Austin ABSTRACT: The Texas 2-STEP (2-Satellite Targeting Experimental Platform) mission is the University of Texas at Austin's (UT-Austin) entry into the University Nanosat-5 (UNP-5) competition, a program sponsored by the Air Force Research Laboratory (AFRL), NASA and the American Institute of Aeronautics and Astronautics. The 2-STEP mission is to perform an autonomous rendezvous and formation flight demonstration using an innovative and inexpensive GN&C system. Two vehicles will be launched in a joined configuration but will perform a separation maneuver on-orbit to drift apart to a distance of 3 kilometers. When commanded, the larger, actively controlled Chaser nanosatellite will autonomously maneuver back to within 100 meters of the smaller, passively controlled Target. The Target vehicle is designed based on the CubeSat platform, a design solution that merges the Nanosat and CubeSat programs in a unique collaboration that has not been previously demonstrated. A standard CubeSat platform has been designed using commercial hardware which can be adapted for a 1U (1-Unit), 2U or 3U CubeSat mission. Use of the CubeSat standard is a responsive space solution that incorporates a modular vehicle design for use in multiple university missions. Adoption of this standard also promotes collaboration between Satellite Design Laboratory programs at UT-Austin. This paper will review the Texas 2-STEP mission and highlight how the Target vehicle is bridging a gap between the Nanosat and CubeSat communities. Elements of vehicle design as well as Chaser-Target team cooperation will also be covered.