Microsats: Design, Development, and Execution of Minimum Missions

DURATION: THREE DAYS
COURSE NO.: 2040

Budget cuts, commercial and international cost competition and continuous expansion in the capabilities of microelectronics are fueling a renaissance in very low cost spacecraft, typically weighing between 1 kg and 100 kg. This course brings the aerospace professional and space systems user community a broad understanding of the philosophies, methods and approaches which underlie this expanding segment of space activity. The course begins with mission design, stressing the interplay of requirements and spacecraft capabilities which allow maintenance of a very low cost program. We examine conventional managerial and technical approaches which do not scale to small programs, and present alternative techniques which have proven successful. Every aspect of a mission is affected by its size and budget, and the course treats each technological area, first reviewing the fundamental principles, and then their application to microspace products. Technical topics include: rocket propulsion and space transportation, both earth-to-orbit and for on-orbit maneuvering and control, orbit mechanics, magnetics, radios and communications, thermal and structural analysis and design, attitude control, digital systems, software development and software/hardware trade-offs, deployable and other mechanisms, and electric power systems. Spacecraft development techniques, parts selection rationale including handling radiation effects and parts qualification requirements, and typical mission development timelines are presented. The course concludes with a look forward at likely new missions and enabling technologies most important to microsatellites.

COURSE MATERIALS:
Include extensive notes and reference materials.

Engineers and engineering managers wishing to lower cost and streamline schedules for both small and large space programs will find the course invaluable. Government policy and program formulation and management personnel, architects and planners for communications, remote sensing and scientific spacecraft will gain fresh perspectives on emerging options in mission design and execution.

Definitions of microsatellites and how they differ from conventional spacecraft. How microsatellite missions are planned to achieve minimum cost with high reliability. Specific technological approaches used in microsatellites for propulsion, attitude control, communications, electric power,structures, thermal control, digital systems and software. Parts and component selection, qualification and testing. Team organization, management, cost and schedule control. Microsatellite program planning and schedule. Development techniques, e.g., analysis and fabrication methods, clean rooms and testing. Mission operations, including ground station design and location. Alternative approaches to quality assurance, documentation, reviews and staffing. Present and future microsatellite missions, including a critical review of several contemporary programs contrasting conventional and microsatellite methods.

1. Demand for Microsatellites.
   

   Overview of technological, budgetary and managerial changes which drive the demand for and capabilities of microsatellites. Definitions of microsatellites. Survey of microsatellite programs.

2. Mission Planning and Architecture.
   

   Interactive design and requirements definition. Alternatives to mission driving requirements. Parts selection criteria and specifications. Ground operations alternatives.

3. Launch Alternatives.
   

   Piggyback and dedicated launch vehicle availability and capabilities. Trade-offs and costs of piggyback versus dedicated launches.

4. On-Board Propulsion.
   

   Role of onboard propulsion. Cold gas, monopropellant and bipropellant systems for small satellites.

5. Orbit Selection.
   

   Why LEO has been the domain of microsatellites. Trade-offs to MEO and GEO. Impact of inclination and altitude on mission capability, architecture and cost.

6. Attitude Control.
   

   Attitude control alternatives and trade-offs. Sensors and actuators. Attitude control algorithms and typically achieved performance.

7. Communication Systems.
   

   Frequency allocations and trade-offs. Modulation, data rate and gain alternatives. Strategies to economically downlink the maximum number of bits. Antennas for micro satellites and ground terminals.

8. Thermal Control.
   

   Passive versus active control. Coatings and blankets. Heat sinks and heat pipes. Orbit and stabilization design for thermal stability. Special thermal requirements.

9. Electric Power.
   

   Solar panels, batteries and charge control alternatives. Power conservation and management. Orbit selection and stabilization design for power.

10. Structures and Mechanisms.
    

    Structural design alternatives. Structural analysis and test. Deployables - procurement, testing and reliability of booms, deployable arrays, steerable arrays, latches and doors.

11. Digital Systems.
    

    Processor and memory alternatives. Radiation effects and parts selection. Code uplinking, software/hardware trade-offs and development environment.

12. Development Approaches.
    

    Clean room, integration and testing, launch vehicle integration and prelaunch activity. Parts selection, redundancy and critical component philosophy.

13. Organization and Management of Very Small Programs.
    

    Geography, documentation, redundant staffing and error checking. Program reviews. Level of authority and group topology.

14. The Future.
    

    Technology drivers - information processing, electric power, attitude determination, propulsion and launch vehicles. New missions. Cost, size and complexity trends.