1. Erik Mueller Michael White

2. Introduction Problem Solution Sensing Frame Testing Q&A Sources

3.  Microthrusters produce <1N of thrust (mN range)  Various propulsion systems (standard, mono, ion drive)

4.  Thruster and forces involved are minute  Must be rugged and durable  Modular design preferable

5.  Sensing is done through direct thrust measurement  Thruster assembly is suspended atop a pole  Secondary force measurement

9.  Single pole for the thruster support, grooved bracket w/ clamping system.  Material likely to be aluminum  Easy to work with compared to steel  Strength is more than adequate for the forces involved

12.  Exhaust plume exerts force on a plate Induced Force Thruster

13.  Uses electronic principle of capacitance  Needle point fulcrums eliminate frictional losses  Double pendulum plates eliminate mechanical noise

15.  Series of amplifiers and filters used to measure the change in signal

16.  Alternatively, use an FM generator per plate  Compare frequency shifts to determine deflection.  Advantage – more resistant to noise and distortion  Disadvantage – potentially more complex

18.  The signal processor will tie into a computer, along with the rocket ignition circuitr.  Both subsystems will be integrated into a single user-controlled program. We are considering Labview at this time.

21.  One rocket test scheduled in the coming weeks to gauge ignition methods & rocket plume  Subsequent test once strain subsystem complete.  Currently creating and testing software with a load-cell.

23.  Week 5-6 Subsystem and structure prototype  Week 6-7 Electrical circuit schematics  Week 5-9 Software composition and test  Week 7-10 Final mechanical component fabrication & revision  Week 9-12 Assembly, testing, revisions if needed  More details on website

24. ItemCost($) Estes motors100 DAQ150 Pipe clamps20 Metal stock500 Strain gauges80 Electronic components100 Paddle Sensors200 Misc fund50 Total1200

26. http://www.grc.nasa.gov http://images.machinedesign.com www.answers.com/topic/piezoelectricity http://www.boeing.com/defense-space/space/bss/factsheets/xips/xips.html Traceable calibration of the 3-axis thrust vector in the millinewton range, EB Hughes and S Oldfield, National Physical Laboratory Direct Thrust Measurement of In-FEEP Clusters, IEPC-2005-235, K. Marhold and M. Tajmar, ARC Seibersdorf research GmbH Rocket Thrust Measurement For an Estes B6-2 Model Rocket Engine, Peter Hyatt, Jeremy LeFevre, Russell Dibb, Bringham Young University Thrust stand for ground tests of solid propellant microthrusters, S. Orieux and C. Rossi and D. Esteve, Review of Scientific Instruments, Volume73, Number 7, July 2002 A Ground Test Rocket Thrust Measurement System, Mary Fran Desrochers, Gary W. Olsen, M. K. Hudson, Department of Applied Science and the Graduate Institute of Technology, University of Arkansas MilliNewton Thrust Stand Calibration Using Electrostatic Fins, Allen H. Yan, Bradley C. Appel, Jacob G. Gedrimas, Purdue University