Plug-and-Play – An Enabling Capability for Responsive Space Missions

1. 2nd Responsive Space Conference April 19-22, 2004 Los Angeles, CA Plug-and-Play – An Enabling Capability for Responsive Space Missions Tom Morphopoulos, Microcosm, Inc., El Segundo, CA L. Jane Hansen, HRP Systems, Inc., Torrance, CA Jon Pollack , HRP Systems, Inc., Torrance, CA James Lyke, Air Force Research Laboratory Space Vehicles Directorate, Albuquerque, NM Scott Cannon, Utah State University, Logan, UT E-mail:tom@smad.com Phone: (310) 726-4100 FAX: (310) 726-4110 401 Coral Circle El Segundo, CA 90245-4622 Web: http://www.smad.com

2. Agenda • Plug and Play • Applicability to Responsive Space • Program Plan • Demonstration Overview • Objectives and Focus • Architectural Elements • Demonstration Configuration • Board Configuration • Bench Configuration • Demonstration Configuration • Demonstration Scenario • Summary and Discussion

3. Plug and Play Motivation • Responsive Space requires a change in approach • Maintaining inventory • Key components “off-the-shelf” • Quick integration • Model/serial number independent • Easy mate and launch • Application of “internet” technologies to space • Resource discovery • Resource management • Resource reconfiguration • Fault tolerance

4. Microcosm SBIR Program Plan • Design for an implementation for 10 to 15 years into the future • Spacecraft configuration and mission determined “on-orbit” • Reconfigurable spacecraft, systems, and subsystems • Smart “components” such as sensors/actuators • Intelligent / reconfigurable structures, power systems, antennas • Create a stepping stone to the larger vision • Identify components that can be created generically and used into the future • Identify components that need not be Attitude Control System (ACS) specific • Fill in for elements that are still under development • Demonstrate system level concept with representative components and configuration • ACS sensors (composite data, over determined data, redundant data) • Simulated actuators • Scalable processors (64 bit, 32 bit, and 8 bit) • “Minimal effort” networks and drivers

5. Demonstration Overview • Objective: Prototype key elements of self-configuring network for “Plug and Play” ACS • Prototype Key Elements • Guidance, Navigation & Control (GN&C) components - actuators and sensors • Realistic spacecraft configuration • Self-Configuring Network • Discovery -- who’s on the bus at any given point • Control -- identify a means of maintaining control of the bus traffic even if components come on and off • Management -- identify data classes and descriptors; assure that data can move from producer to consumer as needed • Plug and Play • Add and subtract “components” from established spacecraft network(s) • Integrate two (or more) spacecraft into a “system of systems” • ACS Focus • Data flow, rates, and requirements all derived from ACS/GN&C application

6. Focus on a Software Solution • Mission Manager: Understands mission objectives, requirements, and success criteria • Resource Manager (RM): Understands resource discovery, data descriptions, health/status • Master Resource Manager: Manages database of resource information • Redundant Resource Manager: copy of Master • Local Resource Manager: Provides API to applications by abstracting physical activity to access data, while providing mechanism for error handling and reporting • Network Manager: Understands addressing, routing, protocol, and interfaces • GN&C Application Software: Understands the required sensor inputs and processing, the control laws by mode, and the actuator distribution and execution

7. Demonstration Approach • – Fault Tolerance • • Redundancy • • Over determined data source • – Data Descriptions • • Subsystem or nodes • • ”Atomic”-level data classes • Create an architecture with multiple networks • Non-Homogeneous Networks • Bandwidth variations • Protocol variations • Data Flow • Push versus pull • Populate the architecture with ACS components • Real sensors (integrated and single axis components) • Modest rate table for spacecraft dynamics - not closed loop control • Nominal GN&C Algorithm • Simulated actuators -- not closed loop control • Demonstrate the RM in varying conditions • Discovery • Nominal operations • With component failure(s) and addition of new components • Demonstrate a system of systems • Multiple non-homogeneous networks integrated together • Plans for Demo with multiple spacecraft integrated together

8. Architectural Elements and Data Flow

9. Board / Bench Configuration 8051 Microprocessor CANBus protocol for Discovery Reporting Command Control Sensor components Actuator indicators

10. Demonstration Configuration • Control Laws: • Bang-bang thruster based control with gains selected for 1.0 Hz operation • 0.1 Hz B-Dot magnetic safe hold mode • GN&C sensors • Gyro 1, 0.5 Hz updates, high accuracy • Gyro 2, 1.0 Hz updates, medium accuracy • Gyro 3, 2.0 Hz updates, low accuracy • Magnetometer,0.1 Hz 3 axis updates • External source for absolute attitude updates • GN&C actuators • 4 off-axis thrusters (represented by 4 LEDs)3 magnetic torquers placed along spacecraft • axes (represented by 3 LEDs)

11. Demonstration Scenario • Initialize with gyro 1, gyro 2, thrusters, magnetometer, and torquers “ON” • Control system selects gyro 2 for 1 Hz attitude determination and 1 Hz thruster based control • “Fail” gyro 2 • Control system maintains 0.5 Hz attitude estimate with gyro 1 • Transition to magnetic B-Dot safe hold control law • Add gyro 3 • RM finds gyro 3, installs drivers • Control system selects gyro 3 for 2 Hz attitude updates • Transition to 1 Hz thruster based control • Add a “new” gyro 2 to system • RM finds gyro 2, installs drivers • Control system selects gyro 2 for 1 Hz attitude updates (gyro 2 has lower noise characteristics) • Maintain 1 Hz thruster-based control • Test for thruster-based control law • Move platform to an offset angle outside of the control dead-zone • Verify that correct thrusters fire • Move platform back to within the dead-zone • Verify that thruster firings stop. • Test for magnetic control law • Thrusters are idle • Magnetic torquers are commanded when platform is moved

12. Summary • Software solution for resource discovery, management, and reconfiguration • Mission Manager • Resource Manager • Network Manager • Reconfigurable GN&C Applications • Scalable and portable to multiple applications • Low level network (CAN) and high bandwidth network (802.3) • 8 bit (8051), 32 bit (ARM), and 64 bit (Intel) Processors • Stack approach to protocol and drivers • Demonstration approach calls for incremental build-up of capabilities • Lower level network capabilities and API to applications • Higher bandwidth network capability “dropped in” • Multiple spacecraft configuration provides “real world” application Microcosm’s Phase II SBIR approach strongly supports “Responsive Space”