No abstract

A torsional impulse balance has been developed as a new diagnostic tool to study fundamental physical processes in micropropulsion systems and laser-surface interactions. The impulse balance has been designed and tested with a robust calibration system to measure impulsive forces with resolution as low as several nano-Newton-seconds. The behavior of the impulse balance was thoroughly studied and characterized. A simple analytical model of the balance's motion was developed from the general equation of motion of an underdamped, harmonically oscillating system. Also, two distinct methods of analyzing the experimental data from the nanoimpulse balance have been investigated. The first method resolves the total impulse as a function of the balance's maximum deflection. The second method enables the determination of the impulse and/or force applied as a function of time from the balance's time-resolved motion.A calibration scheme employing electrostatic actuation techniques is used to experimentally validate the model and impulse measurement techniques. Report Documentation PageForm Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.

Collision avoidance is a topic of increasing importance. The number of satellites in Earth orbit is steadily growing and with the high amount of space debris, either crossing through or resident in orbit, collision probabilities between two such objects can become critical. Small satellite missions usually operate with limited capabilities when it comes to locating potential collision occurrences and deriving the associated collision probability. Accordingly, they have to rely on external organizations, such as the Joint Space Operation Center (JSpOC) and their information system to plan for contingency operations. This paper reviews the benefits of using such an external service for a small satellite constellation. It analyses the relevant data for use in daily operations and shows collision avoidance approaches based on the available data. Conjunction summaries for the RapidEye satellite constellation are evaluated and their influence on the planning of collision avoidance maneuvers is shown.

No abstract

A torsional impulse balance has been developed as a new diagnostic tool to study fundamental processes in laser-surface interactions. Of particular interest are the forces due to processes of laser ablation. With respect to the transfer of momentum, direct measurements of the transient forces can lead to a better understanding and characterization of the efficiency of the impulse that is possible under different configurations. The impulse balance has been designed and tested with a robust calibration system to measure impulsive forces with resolution as low as several nano-Newton-seconds. Initial results of impulses due to ablation from an Nd:YAG laser (532nm) on various metals and other materials are presented.

No abstract

A torsional impulse balance has been developed as a new diagnostic tool to study fundamental physical processes in micropropulsion systems and laser-surface interactions. The impulse balance has been designed and tested with a robust calibration system to measure impulsive forces with resolution as low as several nano-Newton-seconds. The behavior of the impulse balance was thoroughly studied and characterized. A simple analytical model of the balance's motion was developed from the general equation of motion of an underdamped, harmonically oscillating system. Also, two distinct methods of analyzing the experimental data from the nanoimpulse balance have been investigated. The first method resolves the total impulse as a function of the balance's maximum deflection. The second method enables the determination of the impulse and/or force applied as a function of time from the balance's time-resolved motion.A calibration scheme employing electrostatic actuation techniques is used to experimentally validate the model and impulse measurement techniques. Report Documentation PageForm Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.

A torsional impulse balance has been developed as a new diagnostic tool to study fundamental processes in laser-surface interactions. Of particular interest are the forces due to processes of laser ablation. With respect to the transfer of momentum, direct measurements of the transient forces can lead to a better understanding and characterization of the efficiency of the impulse that is possible under different configurations. The impulse balance has been designed and tested with a robust calibration system to measure impulsive forces with resolution as low as several nano-Newton-seconds. Initial results of impulses due to ablation from an Nd:YAG laser (532nm) on various metals and other materials are presented.