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Past Conference Papers:
Plug-and-Play
| Paper Number RS2-2004-5002: Plug-and-Play - An Enabling Capability for Responsive Space Missions | |
| Thomas Morphopoulos (Microcosm), L. Jane Hansen (HRP Systems), Jon Pollack (HRP Systems), Jim Lyke (AFRL), Scott Cannon (USU) | |
| View/Download:Presentation | Paper | |
| Abstract: A self-organizing network concept, leveraging commercial approaches is under development to support responsive space avionics networks. The work is being done in support of an Air Force contract, including the following elements: a network manager (hardware and network medium specific component), mission manager (mission objective specific), and GN&C algorithms for a four state activity (power-on, initialize, nominal GN&C, safe). The current work emphasizes the resource manager, which is responsible for discovering resources as they come on-line. It also manages real-time data descriptions and health/status information for potential consumers of each produced element within the overall network. These mechanisms form a basic system for plug-and-play, in which the components of a system can be rapidly assembled with minimal need to write detailed, low-level code pertaining to the interface of each element. The resulting automation allows system designers to focus on design of higher-level software in an object-oriented fashion, a process that itself might be automated under this concept. | |
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| Paper Number RS3-2005-3002: KUTESAT-2, A Student Nanosatellite Mission for Testing Rapid-Response Small Satellite Technologies in Low Earth Orbit | |
| Trevor Sorenson (University of Kansas), Glenn Prescott (University of Kansas), Marco Villa (University of Kansas), Dewayne Brown (National Nuclear Security Administration), John Hicks (National Nuclear Security Administration), Arthur Edwards (AFRL), James Lyke (AFRL), Thomas George (JPL), Sohrab Mobasser (JPL), JPL (JPL), Scott Tyson (Space Microsystems) | |
| View/Download:Presentation | Paper | |
| Abstract: The Air Force Research Laboratory (AFRL) is interested in using nanosats to perform space experiments, demonstrate new technology, develop operational systems, and integrate advanced responsive space system technology. One potential operational application of nanosats is using clusters of microsatellites that operate cooperatively to perform the function of a larger, single satellite. Each smaller satellite communicates with the others and shares the processing, communications, and payload or mission functions. This type of a distributed system has several advantages: (1) systemlevel robustness and graceful degradation, and (2) distributed capabilities for surveillance and science measurements built into the system architecture. There are a number of technology advancements needed to operationalize and enable tactical missions. These advancements include modular ‘plug-n-play’ satellite architectures and components; high performance tactical downlinks; adaptable, agile propulsion systems, and lean manufacturing, assembly and test. The Kansas Universities’ Technology Evaluation Satellite (KUTESat) program originated at the University of Kansas (KU) in 2002. The technical objective of the program is the development and operation of miniature satellites that can demonstrate and test technologies and techniques necessary to accomplish various government missions. The first satellite, KUTESat-1 Pathfinder, was designed to perform imaging and measure radiation from orbit. The design and construction of this 1-kg satellite helped KU to develop the capability to produce and operate small research satellites. Pathfinder is due for launch in mid-2005. Nanosats are a rapid and low-cost technology platform for the space testing of a broad range of micro-electro-mechanical systems (MEMS) and nanotechnologies as well as new mission architectures. The KUTESat program offers a low-cost solution to the problem of acquiring “space heritage” for new technologies and concepts. These programs can undertake higher risk missions that would be otherwise avoided by more conservative mission planners. Thus new MEMS and nanotechnologies related to avionics, guidance and control, communications, imaging, maneuvering, and instrumentation are offered a rapid and low-cost approach to space testing that will help realize a rapid response space force. The objective of the current program is to develop and fly a nanosatellite to test components, technologies, and concepts that are of use to the AFRL, the National Nuclear Security Administration (NNSA) and the National Aeronautics and Space Administration (NASA), while providing a valuable contribution to the education of students who will soon be entering the space workforce. KU is leading a team consisting of the NNSA Kansas City Plant, the AFRL, and NASA Jet Propulsion Laboratory (JPL) to design and execute the KUTESat-2 mission using a 16-kg nanosatellite based on the Pathfinder satellite with much commonality in the avionics and ground system. The major technologies to be tested include: a miniature distributed and adaptive S-band transceiver; a miniature maneuvering control system; standardized interface (“plug and play”) electronic modules; various MEMS technologies, including a single-axis MEMS gyroscope; a micro sun sensor; an array of miniature dosimeters; and a miniature imager. New capabilities to be tested include a Tracking and Data Relay Satellite (TDRS) communication demonstration with the Sband transceiver, and demonstration of target inspection capability using a deployed inflated target. The KUTESat-2 will be prepared for a launch in 2007. | |
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| Paper Number RS3-2005-3006: HexPak2 - A Flexible, Scalable Architecture For Responsive Spacecraft | |
| Michael Hicks (Lockheed Martin), Michael Enoch (Lockheed Martin), Larry Capots (Lockheed Martin) | |
| View/Download:Paper | |
| Abstract: HexPak2 is a deployable space structure that provides the characteristics essential for successful responsive space missions, including ease of scalability, a geometry naturally adapted for plug-and-play architectures and multiple mission-specific component layouts, and a large deployed aperture from an optimal stowed volume. It consists of hexagonal bays that stack when stowed to efficiently use payload fairing volume, but deploy to a planar structure with deck area many times the fairing cross-section. The large deployed area to fairing size ratio supports large aperture payloads, multiple payloads, heat rejection significantly beyond traditional designs, multiple manifest with minimal wasted support mass, and easy access on orbit for expansion and flexibility for reconfiguration. Since each bay is fabricated and tested individually, and easily accessible from all sides, the time per unit mass to manufacture a complete spacecraft is greatly improved over more traditional structures. For missions that require a large number of platforms, the modular structure offers easy interchangeability of HexPak bays which makes it possible to maintain a consistent production flow even during periods of parts shortages. Standard physical interfaces also allows for commonality in tooling, fixturing, testing and ease of satellite integration. The hexagonal geometry is near optimum for taking advantage of available fairing envelopes and the folded structure is self-supporting which minimizes the need for additional structure to support launch. HexPak has proved to be ideally suited for fairing cross sections as little as 1 meter to as large as 5 meters. | |
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| Paper Number RS3-2005-4001: Key Elements of Rapid Integration and Test | |
| Terrance Yee (MicroSat Systems) | |
| View/Download:Presentation | Paper | |
| Abstract: MicroSat Systems, Inc. (MSI) is currently supporting AFRL in the Roadrunner/TacSat-2 program to demonstrate the development of a tactically useful small satellite in just 14 months. This rapid development requires a flight integration schedule that is less than 4 months between flight hardware arrival and Launch Readiness Review and includes the integration of fourteen experiments and system environmental testing. This paper will review the lessons learned so far in integration and test and the key elements for success in the rapid development process. Management of I&T activities is a critical component in rapid development. Flexible scheduling in complex missions with very short time frames is the key to efficiently using test time. To adapt to the often fluid schedule requirements of I&T, it is necessary to have several options for activities the test team can perform at any given moment. Therefore when Component A runs into problems, Components B, C, or D can be tested during the originally scheduled time with no net impact to schedule. To achieve this objective multiple items must be ready ahead of schedule and several different teams need to work in parallel preparing future tests, debugging troublesome equipment offline, and conducting tests in the test environment. Automated or computer script-driven testing adds tremendous flexibility to the process. By capturing the specific technical expertise for a particular test in the script, any reasonably familiar operator can execute the test,allowing for different experts to work on multiple items. This approach has provided the Roadrunner program enough flexibility to have as many as six different test teams each in various stages of test preparation, execution or documentation. This large number of teams allows for testing in multiple shifts and across an extended workweek, as some teams can have down time while the other teams are working. The use of scripts decouples specific people from specific tests to allow the critical debugging work to happen offline while other testing continues uninterrupted. Script-driven testing also makes handoff to flight operators easier by providing a knowledge bridge between groups. A key element to rapid testing is a streamlined documentation system that efficiently captures requirements, test knowledge, problems, standard procedures, and verification status without unduly burdening the test teams. To this end, the Roadrunner team uses a minimal set of documentation including a daily test log, a simple Problem/Failure database, an Excel verification matrix, simplified test procedures and “Test Flows”, which are brief documents that tie requirements to scripts and set the framework for the test. | |
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| Paper Number RS3-2005-4003: Software as a Tall Poll in Achieving Rapid Configuration and Integration | |
| Kenneth Center (Design_Net Engineering), Gerald Murphy (Design_Net Engineering), Robert Strunce (Star Technology Corporation) | |
| View/Download:Presentation | Paper | |
| Abstract: The concept of “configurable” spacecraft that can be quickly assembled to meet the needs of operationally responsive space has many elements that make its realization challenging. Having certain standard components “on the shelf” reduces lead times, standardizing interfaces improves the ease of integration and can lower harness complexity and cost, but how do we actually deal with the configuration process and how can we assemble the software rapidly and reliably? Software is a major cause of mission failure and without attention to this aspect of the problem, reliable responsive configuration will never be possible. Design_Net Engineering, under an SBIR contract from MDA, has teamed with Star Technologies to develop a process, an architecture, and a set of tools to be used in enabling this rapid configuration. The tools are built upon Star Tech’s Spacecraft Dynamics Tool (SDT) and the architecture of a unique modular software design developed by Design_Net on previous flight programs. The tool is a system design and configuration utility which enables precise simulation of the on-orbit behavior of the spacecraft and its payload. The architecture allows scripted operations to be authored and modeled before freezing the configuration of the spacecraft. After complete mission investigation in the virtual environment with the selected configuration, the flight code can be assembled “at the push of a button.” Portions of this program are being integrated into the capability of the flight Testbed at the Air Force Research Laboratories (AFRL) in Albuquerque, New Mexico. | |
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| Paper Number RS3-2005-5001: Space Plug-and-Play Avionics | |
| Jim Lyke (AFRL), Don Fronterhouse (Scientific Simulation), Scott Cannon (USU), Denise Lanza (Space Applications International Corporation) | |
| View/Download:Presentation | Paper | |
| Abstract: The Air Force Research Laboratory is developing a system for rapidly building spacecraft based on adapting “plug-and-play” (PnP) approaches for use in space. This space plug-and-play avionics (SPA) system is based on an interface-driven set of standards intended to promote the rapid development of spacecraft busses (platforms) and payloads. As such, SPA is an open systems framework, combining commercial standards (such as USB) with carefully chosen hardware and software extensions necessary for modern real-time embedded systems (e.g. fault tolerance, higher power delivery, self-description). This paper will review the status of SPA and the efforts being made to standardize SPA through the AIAA. | |
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| Paper Number RS3-2005-5004: Reconnaissance Payloads for Responsive Missions | |
| Charles Cox (Goodrich Optical and Space Systems Division), Stanley Kishner (Goodrich Optical and Space Systems Division), Richard Whittlesey (Goodrich Optical and Space Systems Division), Fredrick Gilligan (Goodrich Optical and Space Systems Division) | |
| View/Download:Presentation | Paper | |
| Abstract: Operationally responsive Electro-Optical (EO) imaging capability exists and is routinely used to provide intelligence information to the tactical war fighter. This capability is provided by Goodrich Reconnaissance systems having “plug and play” interfaces to strategic (i.e., U-2) and tactical airborne platforms. These operational systems have visible, IR and multispectral capability, and the resulting data readily interface into an existing infrastructure providing timely information to theater commanders. These airborne operational systems can be modified to provide reconnaissance capabilities from space to support the Operationally Responsive Space (ORS) vision. This paper describes these systems, summarizes some of the utility provided by them, and discusses hardware modifications and operational scenarios consistent with lowcost mission requirements. This approach, the modification of existing airborne operationally responsive EO imaging systems, provides a low cost alternative to top-down special-purpose development and leverages a continually evolving product stream to provide ORS payloads. | |
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| Paper Number RS4-2006-1002: Fractionated Space Architectures: A Vision for Responsive Space | |
| O. Brown (Defense Advanced Research Projects Agency), Paul Eremenko (Booz Allen Hamilton) | |
| View/Download:Presentation | Paper | |
| Abstract: The advent of the integrated circuit some four decades ago set off mankind’s insatiable thirst for computational power. The quest to quench this desire led to the development of increasingly more sophisticated computers. Microchips sprouted ever greater numbers of transistors, choking buses, and forcing memory banks to struggle to keep up. The novelty of micro- and minicomputers was quickly trumped by the sheer computational prowess of supercomputers. And so the trend continued. In a matter of two decades, however, this drive towards greater processing power culminated in mammoth mainframes whose rapidly increasing complexity, fragility, and cost quickly outpaced the capability gains. A scant few years into the second decade of the era of the integrated circuit, the availability of inexpensive, mass-produced microcomputers, and the advent of fast, seamless internetworking ensured the relegation of the large monolithic mainframes to obsolescence and obscurity. Spacecraft have followed a trajectory that is uncannily parallel (and, of course, technologically intertwined) to the history of high-end computing. Borrowing the historical analogy, we posit that the era of distributed space architectures has likewise arrived. The gargantuan monolithic systems deployed to orbit today have grown too large, too complex, too fragile, and consequently much too expensive; furthermore, these trends have not been offset by commensurately rapid growth in capability. We propose a fractionated architecture for space systems, whereby a satellite is decomposed into a heterogeneous set of components which interact wirelessly. In the extremum, the fundamental functionality of most space systems is the reflection of photons back to earth. Thus, assuming that the requisite photon collection, processing, and re-radiation can be accomplished, the spacecraft need be nothing more than a collection of free-floating “pixie dust.” In the realm of the foreseeable technological future, however, there are a handful of schema for severing and distributing the functionality of a monolithic spacecraft. Perhaps the most basic is fractionating the spacecraft along its data channels, resulting in a loose cluster of networked spacecraft modules. Somewhat more challenging is also fractionating the power system and disseminating power wirelessly among the modules. At the technological horizon is also fractionating the propulsion and stationkeeping functionality, also necessitating the wireless transmission of forces and torques. The fractionated architecture is likely to incur an aggregate mass impact versus its monolithic counterpart (although it is noteworthy that at least one massive component may shrink – the flywheels necessary to ensure payload pointing accuracy need only be responsible for stabilizing and pointing the payload module, not the entire spacecraft). The impact on overall system cost is ambiguous since the cost impact due to greater system mass is at least partially offset by learning curve and mass production effects across the multitude of modules. For a constant required level of functionality, however, the fractionated architecture dramatically outperforms its monolithic counterparts in its value proposition. It affords its user/operator greater flexibility in the form of system scalability, reconfigurability, and adaptability (including multi-payload functionality). It dramatically increases robustness and survivability. It allows the isolation of the payload for both improved security and increased pointing accuracy. It lowers possible increases in lifecycle cost and decreases schedule risk by decorrelating failure probabilities of the various component subsystems and multiple payloads. It improves responsiveness by allowing incremental capability deployment, by enabling the utilization of small launch vehicles for the emplacement of massive orbital capabilities, and by shifting the deployment decision chain from the strategic to the tactical level. Perhaps most importantly – and much like the internetworked microcomputer – it commoditizes the space industry and transforms it from an exotic boutique to a customer-driven, cost-competitive enterprise. The technologies needed to make fractionated space systems a reality are well within reach. They potentially include responsive and inexpensive small launch vehicles, highly secure ultra wideband inter-module data links (which may also provide relative navigation capabilities for the spacecraft modules), efficient radio frequency power transmission, passively stable Keplerian cluster orbits, and mass-produced, inexpensive, space-qualified satellite components (many with their legacy in the newly-emergent field of unmanned aerial vehicles). More esoteric technology options include very high frequency power beams, laser power transmission, and remote force and torque transmission through electromagnetic induction. The Defense Advanced Research Projects Agency (DARPA) has been studying the fractionated architecture concept and is poised to commence an initiative entitled F6 – short for Future Fast, Flexible, Fractionated Formation-Flying Spacecraft utilizing Information eXchange, and incidentally a tornado of unimaginable strength on the Fujitsu scale – that will mature the associated technological, architectural, and organizational advancements necessary for an onorbit demonstration of a fractionated spacecraft. A brief discussion of the vision for F6 concludes. | |
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| Paper Number RS4-2006-1006: Using Proven Aircraft Avionics Principles to Support a Responsive Space Infrastructure | |
| Randy Black (Honeywell Space Applications) | |
| View/Download:Presentation | Paper | |
| Abstract: Creating an engineering environment that supports responsive space involves a variety of interrelated disciplines. Included within these disciplines is the ability to quickly re-configure systems through plug-and-play hardware and software. Plug-and-play hardware as a concept has been progressing well throughout the electronics industry. Plug-and-play software has been somewhat more challenging. While some advances have been made through object-oriented architectures and model-based autocoding, software lags behind hardware in this area. Honeywell has experienced significant success for the past ten years fielding plug-and-play software at the application level. Using a combination of time and space partitioning, table-driven operations, and robust off-line development tools, Honeywell’s Integrated Modular Avionics (IMA) has produced significant savings in development cost and schedule. More importantly, modifications to either hardware or software are quickly and easily integrated into the overall system with minimal re-certification required. During the past decade, Honeywell has produced multiple implementations of this advanced avionics technology. One lesson learned is that specific implementation details are not as important as designing to key architectural principles. This paper describes several of those principles that have a proven track record of enabling rapid reconfiguration of system architectures. Architectural principles that support plug-and-play software applications, as well as minimizing the impact of hardware modifications, provide the core of a system design that is integral to an overall responsive space infrastructure. | |
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| Paper Number RS4-2006-3001: Analysis of Modular Spacecraft Bus Design for Rapid Response Missions | |
| Lucy E. Cohan (Massachusetts Institute of Technology), Richard-Duane Chambers (Massachusetts Institute of Technology), Rachel K. Lee (Massachusetts Institute of Technology), Col. John Keesee (Massachusetts Institute of Technology) | |
| View/Download:Presentation | Paper | |
| Abstract: Rapid Response spacecraft are becoming more essential due to current affairs. The long development and testing times of typical satellites necessitate a change of paradigm to accommodate responsive space timeline requirements. One necessary component of this paradigm shift is a standardized bus. A standardized bus allows for a minimal amount of bus redesign and testing for each mission. Instead of forcing the bus to conform to the payload, the payload must conform to a set of predetermined requirements imposed by the bus. By reducing the need for satellite redesign and test, standardized buses allow for mission readiness in a matter of weeks rather than years. However, using standardized buses reduces payload flexibility and leads to buses that are oversized, overdesigned, or otherwise inappropriate for a particular payload. This study proposes that a modular bus might provide standardized interfaces for responsiveness, yet still provide some flexibility to match the needs of the payload. However, modularity comes at a price, introducing inefficiencies and testing cost. This paper presents a quantitative analysis of the cost and efficiency of two competing standardized bus options: a traditional monolithic design and an emerging modular architecture. The study further attempts to quantify this tradeoff and determine the optimal degree of modularity for a responsive satellite bus. The degree of modularity is determined by specifying which, if any, subsystems should be considered as separate modules that can be upgraded or replaced, and which subsystems should be a part of an integrated bus common to every mission. The study has been undertaken using MATLAB® simulations. The individual simulation components represent various satellite subsystems, as well as satellite demand, cost, testing time, and inventory size. The codes are run to determine the efficiency, cost, reliability, response time, and inventory of each configuration of modular and integrated subsystems across a range of payloads. Specifically, this study explores payloads of the following three types: a communications payload in low earth orbit, a communications payload in highly elliptical orbit, and an optics payload in low earth orbit. The efficiency is defined as being the excess mass, power, and volume capacity created by utilizing the standardized bus that is designed to work with many payloads as opposed to a monolithic bus designed specifically for the given payload. The response time is defined as the time from the mission call to the time that the satellite is ready for launch. Additionally, there is an efficiency associated with the amount of inventory required to maintain mission readiness. The study establishes the optimal combination of modular and integrated subsystems, as well as testing strategy and inventory for responsive space missions of these types. | |
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| Paper Number RS4-2006-3005: ORS Phase III Bus Standards Status | |
| J. Christopher Garner (US Naval Research Laboratory), Michael Hurley (US Naval Research Laboratory), Gurpatap S. Sandhoo (US Naval Research Laboratory), Eric J. Finnegan (Johns Hopkins University/Applied Physics Laboratory), Patrick A. Stadter (Johns Hopkins University/Applied Physics Laboratory), Brian Kantsiper (Johns Hopkins University/Applied Physics Laboratory) | |
| View/Download:Presentation | Paper | |
| Abstract: The U.S. Naval Research Laboratory and the Johns Hopkins University/Applied Physics Laboratory are collaborating with many industry partners to write bus standards for responsive spacecraft buses as part of the ORS/JWS Phase III. The next Phase, Phase IV led by SMC, will use the standards as input to the procurement of responsive spacecraft buses in 2008. More than 8 industry partners (Spectrum-Astro, Design-Net, Swales, Orbital, Raytheon, Loral-Microcosm, and Microsat Systems Inc) are under contract to NRL to participate in the integrated systems engineering team (ISET). The ISET has been meeting since June 2005 and has produced the first drafts of the payload developers guide (PDG) and the bus standards documents. Currently, an NRL/APL team is working to develop a prototype spacecraft bus to mature portions of the standards and supply the spacecraft bus for the TacSat 4 mission. This paper will discuss the ISET team process in developing the bus standards and the progress of experimentation with the prototype bus. Phases I-III of this effort are funded by OSD’s Office of Force Transformation, Phase IVeffort will be funded by SMC. | |
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| Paper Number RS4-2006-3006: HexPak Testbed Development | |
| Michael Hicks (Lockheed Martin Advanced Technology Center, Palo Alto, CA), Michael Enoch (Lockheed Martin Advanced Technology Center, Palo Alto, CA), Larry Capots (Lockheed Martin Advanced Technology Center, Palo Alto, CA) | |
| View/Download:Presentation | Paper | |
| Abstract: HexPak is a scalable spacecraft structure with the requisite features that enable responsive space missions. The structure consists of hexagonal equipment/payload bays with embedded harnessing to support multiple mission-specific component layouts. Scalability is supported via embedded network connectivity for plug’n’play avionics and expansion bays. The hexagonal bays are stacked for launch in a self-supporting structure which efficiently packs in the launch fairing, and deploys on orbit to form a large deployed aperture for payload equipment. The large deployed area provides large aperture payloads un-inhibited viewing angle. Since the structure is self-supporting, multiple payloads and multiple manifest are possible with minimal mass impact due to launch support structures. Since each bay is fabricated and tested individually, and easily accessible from all sides, the time/unit mass to manufacture a complete spacecraft is greatly improved over more traditional structures. For missions that require a large number of platforms, the modular structure offers easy interchangeability of HexPak bays which makes it possible to maintain a consistent production flow even during periods of parts shortages. Standard physical interfaces also allow for commonality in tooling, fixturing, testing and ease of satellite integration. The hexagonal geometry is near optimum for taking advantage of available faring envelopes and the folded structure is self-supporting, which minimizes the need for additional structure to support launch. A full-scale mechanical testbed for demonstration of HexPak deployment was built last year and is described, along with the physical integration of a JINI based plug’n’play network onto the structure. Because the structure and C&DH system are physically scalable, their combination provides a clear route for the transfer of the rapid integration advantages of responsive space to more traditional missions. | |
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| Paper Number RS4-2006-4003: Development of the Tactical Satellite 3 for Responsive Space Missions | |
| Thomas M. Davis (AFRL), Capt. Stanley D. Straight (USAF AFRL) | |
| View/Download:Presentation | Paper | |
| Abstract: Numerous Department of Defense studies show implementing a responsive satellite capability provides for significant military utility to augment or surge current space capabilities. The TacSat concept explores the capability/technological maturity of small, low-cost satellites with the most prominent efforts currently being conducted within the Science and Technology (S&T) Program. In addition to providing for ongoing innovation and demonstration in this important technology area, these S&T efforts also help mitigate technology risk and establish a concept of operations (CONOP) for future acquisitions. TacSat efforts underway by the Air Force Research Laboratory (AFRL) and the Naval Research Laboratory (NRL) are focused on demonstrating small (<500kg), operationally responsive, low-cost satellite and launch capabilities to support warfighter. AFRL’s Space Vehicles Directorate is leading the Tactical Satellite 3 (TacSat-3) team and partners include Space and Missiles Center Detachment 12, the Army Space Battle Laboratory, the Air Force Space Warfare Center, the Office of Naval Research, and the DoD Office of Force Transformation. Building on the experiences with TacSats 1 and 2, TacSat-3’s mission was vetted through a formal payload selection process with Air Force Space Command (AFSPC) and Combatant Commands (COCOMs). TacSat-3’s mission was selected for specific capabilities to meet user needs, and to demonstrate those capabilities within cost and schedule constraints. A building block for Operationally Responsive Space, TacSat-3 will experiment with a Hyperspectral Imaging (HSI) capability direct to the tactical warfighter within 10 minutes of a collection opportunity. The TacSat-3 demonstration features a low cost “plug and play” modular bus and low cost militarily significant payloads – a Hyperspectral Imager and a secondary payload demonstrating data exfiltration provided by the Office of Naval Research. TacSat-3 will demonstrate evolutionary steps and traceability towards objective system goals for the capabilities and processes including rapid response to a user defined need for material detection and identification, and battle damage assessment. Additionally, it will demonstrate traceability to enable launch processing at the launch base faster than 7 days. Finally, it will feature a rapid development of the space vehicle and integrated payload and spacecraft bus by using components and processes developed by the Operationally Responsive Space Modular Bus program. Design constraints established for the TacSat-3 program include a total program cost to be less than $50M, to fit on a low cost responsive space booster and a satellite weight of less than 400 kilogram, with a build time for payload and modular bus of less than 18 months. The TacSat-3 CONOPS breaks old paradigms and gives COCOMs first realistic opportunity for responsive, dedicated space capabilities at the operational and tactical level. The TacSat-3 spacecraft will collect and process images and then downlink material ID text and geolocation or downlink full data image using a Common Data Link. An in-theater tactical ground station will have the capability to uplink tasking to spacecraft and will receive full data image. | |
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| Paper Number RS4-2006-6001: Issues and Implications of the Thermal Control System on the "Six Day Spacecraft" | |
| Andrew D. Williams (AFRL), Scott E. Palo (University of Colorado) | |
| View/Download:Presentation | Paper | |
| Abstract: The traditional approach to satellite design is a customized and highly optimized satellite bus. The primary design driver is to minimize mass but often at the expense of time and money. To meet the goals of Operationally Responsive Space (ORS), the satellite must be adaptable to different missions, changing threats, and emerging technologies. One of the subsystems that will be challenging for the development of robust and modular architectures is the Thermal Control Subsystem (TCS). To design the TCS, virtually every aspect of the mission, the satellite, and the components must be known. The overall goal of the engineer is to reduce the mass of the system by trading cost and engineering time. As a result, every design is unique and requires extensive design, modeling, analysis, and test programs. One philosophical approach to achieve the goals of responsive space in the near term is to separate the design and engineering of the payload from the bus. The bus would have a standard design providing a specific set of baseline capabilities and would have limited upgradeability. The disadvantage with most standardized bus development programs is that the bus eventually becomes obsolete and must be completely redesigned as new technologies are developed. One of the goals of the ORS program is the development of technologies that provide robust and flexible bus designs. The Space Avionics Plug-and-Play (SPA) system in development by Air Force Research Laboratory, Space Vehicles Directorate addresses the software and electrical interfaces, but other efforts are needed to address the mechanical and thermal interfaces. For responsive space, the ideal TCS would be modular and robust to accommodate the wide range of orbits, components, and payloads with minimal survival heater power. In addition, the design and assembly time must be dramatically decreased. The ultimate goal would be a TCS with an inherent plug-and-play capability. One hindrance is that the missions, payloads, and requirements for ORS are still somewhat nebulous. As a result, bus architectures and specific components have not been identified, which makes it difficult to derive even initial thermal system requirements. To provide a baseline for the TCS design and to help bound the problem for the development of thermal plug-and-play systems, the range of external and internal heat loads for small satellites are evaluated. From this analysis, the worst hot and cold cases are identified. Using these two cases, various design parameters are evaluated, and the feasibility of a one-size-fits-all approach is assessed. Finally, critical design parameters are identified and recommended figures of merit are established. | |
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| Paper Number RS4-2006-6002: Java-based Plug-n-Play (Flight) Control Systems for Responsive Space | |
| Constantine Orogo (Lockheed Martin Advanced Technology Center), Michael Enoch (Lockheed Martin Advanced Technology Center), Donald Flaggs (Lockheed Martin Advanced Technology Center) | |
| View/Download:Presentation | Paper | |
| Abstract: A major challenge to achieving a usable and useful “6-day spacecraft” for Operationally Responsive Space is the ability to rapidly compose the system to perform both the needed mission- and spacecraft-oriented functionality using the available "Plug-N-Play" (PnP) spacecraft components. Physical assembly of the PnP spacecraft components is a necessary, but insufficient condition for achieving a fully realized operational system. The assembled system needs to provide the functional capabilities to support the intended mission and also needs to provide the functional capabilities to ensure the operational health and safety of the resulting spacecraft. A preliminary service-oriented spacecraft architectural model to provide a reusable infrastructure is under development as part of the AFRL Responsive Space Testbed effort. The Lockheed Martin ATC is pursuing the development of a Java-based distributed architecture environment that supports this service-oriented, reference spacecraft architectural model. This work draws on the research experience at the LM ATC since the mid-1990s directed towards the problem of performing multi-fidelity, “composable” simulations, with the ultimate objective being the ability to simulate the entire life cycle of a space system. A key component of this approach involves a simulation architecture that is based on spacecraft services, much like the service-oriented models now widely used in the consumer marketplace. It is but an evolutionary step to extend this approach from simulation to operations. To seamlessly span the entire range from simulation to operations, a single vertically integrated software architecture was needed. The Java-based distributed architecture provided such an environment with its evolution from desktop, to enterprise, to mobile devices, and now to real time systems. The Java environment addresses the complexity needed for operational simulations and ultimate deployment for integrated spacecraft flight and payload control systems. The Real Time Specification for Java (RTSJ) supports hard real time, soft real time and non-real time processes all interoperating within the same virtual machine. Initial prototyping is being done using IBM’s Real Time Java (RTJ) implementation of the RTSJ. Along with the development of the Java platform came the development of a multitude of supporting APIs, and one in particular, the JINI protocol, which supports the operation of dynamically changing networks of distributed services (and devices). Using JINI, running as a non-real time process within IBM’s RTJ, provides the rich set of Plug-N-Play capabilities needed to demonstrate both automatic configuration, as would be needed for I&T, as well as for operational fault tolerance and reconfigurability needed for on-orbit operations. | |
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| Paper Number RS4-2006-6003 alt: Implications of Responsive Space on the Flight Software Architecture | |
| Jonathan Wilmot (NASA Goddard Space Flight Center) | |
| View/Download:Presentation | Paper | |
| Abstract: The Response Space initiative has several implications for flight software that need to be addressed not only within the run-time element, but the development infrastructure and software life-cycle process elements as well. The run-time element must at a minimum support “Plug & Play”, while the development and process elements need to incorporate methods to quickly generate the needed documentation, code, tests, and all of the artifacts required of flight quality software. Very rapid response times go even further, and imply little or no new software development, but using only pre-developed and certified software modules that can be integrated and tested through automated methods. These elements have typically been addressed individually with significant benefits, but it is when they are combined that they can have the greatest impact to Responsive Space. The Flight Software Branch at NASA’s Goddard Space Flight Center has been developing the run-time, infrastructure and process elements needed for rapid integration with the Core Flight software System (CFS) architecture. The architecture consists of three main components; the core Flight Executive (cFE), the component catalog, and the Integrated Development Environment (IDE). This paper will discuss the design of the components, how they facilitate rapid integration, and lessons learned as the architecture is utilized for an upcoming spacecraft. | |
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| Paper Number RS5-2007-7001: A Network Broadcast Service for SpaceWire Plug and Play | |
| Allison Bertrand (Southwest Research Institute), Sandra G. Dykes (Southwest Research Institute), Robert Klar (Southwest Research Institute), Christopher C. Mangels (Southwest Research Institute) | |
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| Abstract: The foundation for low-cost responsive missions depends on the existence of standardized components with the capability to be quickly tailored to the current need. The automation of network configuration and communication services is necessary to rapidly assemble and deploy Plug and Play spacecraft. On-board communications over SpaceWire networks are currently being expanded to support the Plug and Play model. The term “Plug and Play” is used to describe automatic device recognition as well as automatic network configuration and the discovery of services at the application layer. For example, the Address Resolution Protocol (ARP) and the Dynamic Host Configuration Protocol (DHCP) can be considered Plug and Play services. In this paper, we focus on such automatic network services for SpaceWire. SpaceWire is a lightweight switched network that was developed for the space environment. It supports the current trend moving from shared bus architectures with mission-specific protocols towards on-board switched networks with established network protocols. The use of standard protocols such as Internet Protocol (IP) and operating system (OS) network stacks as part of the SpaceWire standard would reduce mission development time, errors, and cost. Ethernet is the dominant switched network technology on Earth and is one contender for the space environments. In Ethernet, the switches are responsible for link-layer broadcasts. To avoid forwarding loops, the switches must continuously learn network topology and build a minimum spanning tree for message delivery. However, these algorithms add complexity and circuitry which increases mass and power requirements. SpaceWire, an ESA standard, is gaining popularity because of its simple circuitry, low power consumption, and high-link speed. Despite SpaceWire’s many advantages, it does not have a link-layer broadcast mechanism. Broadcasts are necessary to support automatic network configuration and discovery software such as the ARP and the DHCP. Consequently, address resolution and host IP assignments for SpaceWire networks currently require manual configuration. This presentation will describe the design and implementation of a link-layer broadcast service for SpaceWire. Our link-layer broadcast mechanism is implemented in the hosts rather than in the SpaceWire switches. The design is compliant with the SpaceWire specification and can be implemented solely within the interface driver software. No changes are required to the SpaceWire specification, routers, or host interface hardware. The algorithm uses the concept of a SpaceWire subnet, which consists of a router and its directly connected hosts. The advantage of a subnet approach is that broadcast messages are propagated over a large multi-router SpaceWire network using only port addressing or the SpaceWire packet distribution mechanism. We believe that supporting standard protocols such as ARP, DHCP, and other broadcast-based protocols greatly simplifies the administration of spacecraft on-board networks and reduces mission development time. Standard communication protocols also provide compatibility and interoperability between a wide range of existing network applications. This is an important step towards building Plug-and-Play spacecraft with automatic network configuration, resulting in more rapid development and deployment of SpaceWire-based responsive missions. | |
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| Paper Number RS6-2008-4004: Design and Use of a Variable Thermal Layer (VTL) for Rapid Satellite Component Intergration | |
| William Hafer (Infoscitex Corporation), Nicholas Vitale (Infoscitex Corporation), Chris Macris (Enerdyne Solutions), Robert Ebel (Enerdyne Solutions), John McCullough (Enerdyne Solutions), Andrew D. Williams (Air Force Research Laboratory, Space Vehicles Directorate) | |
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| Abstract: Operationally Responsive Space (ORS) requires the design and assembly of small tactical satellites in greatly reduced timeframes. This capability can be achieved with a generic plug-n-play satellite bus implementing modular structural, electronic and thermal interfaces for payload and supporting components. Modular thermal interfaces are particularly difficult to implement, due to the wide range of thermal characteristics of spacecraft components. To address this need, Infoscitex is developing the Variable Thermal Layer (VTL), a modular interface component for insertion between the satellite bus and a range of critical components. The VTL functions as a thermal gasket that is inserted between the bus and the component's baseplate. The thermal behavior of the VTL can be varied to allow precise control of thermal flux into or out of the component. VTL is implemented as an array of thermo-electric devices (TEDs) embedded in an otherwise insulating matrix, such as an MLI or aerogel blanket layer. Each TED can actively pump heat in either direction, either warming or cooling the component. Maximum heat loads on the VTL occur during the spacecraft hot cycle, when heat must be removed from the component down the thermal gradient and into the bus. Working with the thermal gradient allows the TEDs to operate efficiently, at a coefficient of performance (COP) of 5 or greater, meaning that the heat is removed from the component is five times the power supplied to the TEDs. By applying active thermal pumping over baseline conduction, the VTL can achieve “effective” thermal conductivities ranging from a minimum of 10 W/m2-K, up to a maximum of 700 W/m2-K. This performance range addresses many spacecraft components relevant to a tactical satellite bus. Some components whose thermal requirements exceed VTL capabilities, such as some electromagnets, can be integrated with the use of a thermal doubler or similar mechanism to spread the thermal load. The distributed nature of the TED array allows the VTL to conform to the hot-spot distribution of a given component, as well as matching the variation of the component’s thermal requirements in time due to changes in operating mode and orbital position. The footprint of the VTL (L, W) is sized specifically to each component. All other attributes of VTL are unchanged from component to component and spacecraft to spacecraft. | |
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| Paper Number RS7-2009-5001: P-n-P Attitude Control System for Responsive Space Missions | |
| Frederick Leve (University of Florida), Vivek Nagabhushan (University of Florida), Norman Fitz-Coy (University of Florida) | |
| View/Download:Presentation | Paper | |
| Abstract: The past several Responsive Space Conferences (RS1-RS6) have developed and debated the concept of responsive space missions and the potential utility of small satellites to carry out such missions. Typical missions for responsive satellites will include earth disaster management, earth monitoring, directional communication and imaging. Systems and technologies that would augment the functionality of small satellites and extend their utility to these missions need to be developed. Also these system components should be available in prepackaged units with standardized interfaces so that they can be quickly configured into satellites that best meet the requirements of the responsive mission. One such key component discussed in this expose would enable rapid retargeting and precision pointing (R2P2) of small satellites thus enabling them for responsive missions. This feature (R2P2) is an absolute necessity for small satellites since they typically are in low earth orbits, have smaller swath, and larger angular speeds. The paper presents a fully developed “black boxed” attitude control system (ACS) using control moment gyroscopes (CMG) prepackaged into a ½ U1 plug-n-play device with standard electrical and mechanical interfaces. A CMG-based ACS is well suited for the three axis attitude control of R2P2 small satellites since they have the capacity to generate large torques, are capable of high precision, and consume relatively low power. A comparison justifying the choice of CMG over reaction wheels, magnet coils, and other types of actuators is detailed in the paper. Due to their low inertia small satellites are more susceptible to perturbations due and thus pose a challenge for attitude control systems. The analysis of the dynamics of the CMG itself presents a challenge, as the effects of bearing friction, gimbal accelerations, variable inertia, and perturbations due to flywheel eccentricities on the performance of the system can no longer be neglected. Packaging of the hardware into a compact space under acute mass constraints poses mechanical design challenges. The paper discusses in detail the design and approaches adopted in overcoming these challenges and developing a fully functional plug-n-play attitude control device for small satellites. The paper also discusses control strategies and steering logics for improving the performance of the device, some simulations and experimental test results. | |
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| Paper Number RS7-2009-5002: Building SPA PnP Satellites | |
| Donald Fronterhouse (PnP Innovations, Inc), Maurice Martin (AFRL RVSE) | |
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| Abstract: The space community, led by AFRL, started developing spacecraft plug and play concepts and standards in 2004 and has resulted in the Space Plug and play Avionics (SPA) Standards. AFRL has undertaken two efforts in small satellite development to both solidify the technology and to demonstrate the benefits. The Plug and Play Satellite (PnPSat) utilizes the SPA-S interface standard and demonstrated that rapid development, integration and testing is possible. The second effort is PnPSat-2 that uses the next generation of SPA components for a larger bus focused on ORS needs to make real the promise of custom performance at commodity prices. The SPA standard interface has proven critical to the development of design tools that both select (based upon performance requirements) and place (based upon restrictions such as mass and power balance) components. The Satellite Data Model (SDM) method of query and discovery enables the development of modular, single purpose applications that support autonomous flight software in a distributed computing system. The utilization of a data centric architecture (as opposed to component centric) insolates software developers from both specific hardware components and data network topology. The SPA standard interface reduces the need for many specialized test methods resulting in major reductions in test time. This paper will present the steps used in designing, building, and testing SPA PnP satellites. | |
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| Paper Number RS7-2009-5004: Autonomous PnP Flight Software | |
| Kenneth Center (PnP Innovations, Inc), Donald Fronterhouse (PnP Innovations, Inc), Maurice Martin (AFRL VSSE) | |
| View/Download:Presentation | Paper | |
| Abstract: Most space markets could benefit immensely from satellites that not only start their service lives as soon as possible, but can perform their on-orbit roles with minimal intervention from ground operations. The development of flight software techniques that addresses both of these issues has been ongoing at the Air Force Research Laboratories (AFRL) Responsive Space Testbed (RST) for a number of years. The Space Plug & Play Avionics (SPA) standards define the means by which software (and hardware) components installed on a networked spacecraft bus deliver their data interfaces and self-organize into a coherent, functional system. A collection of modular, pre-validated software applications are maintained in a “virtual store room” and are called upon to configure tailored mission capabilities based upon operational needs. Mission “Activity Agents” encapsulate the logic and sequences necessary to accomplish satellite operations autonomously. These Activity Agents coordinate their execution using on-orbit planning resources and a priority-based scheduler. The PnPSat mission was the first formal application of these techniques. In the course of the program a spectrum of software tools were authored to support the rapid design, prototyping, and testing of flight software modules for SPA-based satellites. AFRL is now populating their Operationally Responsive Space (ORS) assembly depot with an assortment of hardware and software components sufficient to build a reasonably diverse array of tactical small satellites. The tools being used, and the philosophies employed in their application, are ready for exposure to the larger space community. PnP Innovations is leading the charge to infuse this technology by hosting of a series of technical workshops. Topics will range from orientation of the new user to the fundamentals of SPA-based software, to more advanced topics - such as the creation and coordinated simulation testing of complex mission activity agents. | |
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