S.C.R.A.T. EXPERIMENT: A STUDENT EXPERIENCE

Transcription

1 CISAS G. Colombo, University of PADOVA, Via Venezia 15, Padova (ITALY) S.C.R.A.T. EXPERIMENT: A STUDENT EXPERIENCE 1st Symposium on Space Educational Activities Padova, 10th December 2015 Matteo DUZZI (matteo.duzzi@gmail.com) Lorenzo OLIVIERI, Alessandro FRANCESCONI

2 CONTENTS: Introduction Concept Milestones Problem solving approach Flight & Data Analysis Results PUMP BATTERY Integration & Launch LOAD CELL CGA LOAD CELL DAA ELECTRONICS DATA HAND. Lessons Learned & Conclusions Page 2 of 19

3 THE REXUS-BEXUS (RX/BX): Collaboration among ESA, DLR and SNSB Part of ESA «Hands-on» student activities REXUS - Rocket EXperiments for University students BEXUS - Balloon Experiments for University students Standard BEXUS Schedule: ESA PDR Selection Preliminary Workshop Design Sounding Rocket Rview (100 km 3 min. 0-g) CDR Critical Design Review Flight EAR Experiment Campaign Acceptance (ESRANGE) Stratospheric Balloon Review (25 km 3-5 hours) Page 3 of 19

4 S.C.R.A.T. EXPERIMENT S.C.R.A.T.: Spherical Compact Rechargeable Air Thruster - Objectives: Development of a cold-gas-actuator (thrust mn) Attitude control of small balloons and airships Propulsion of autonomous micro-air-vehicles (MAV) Test of the actuator during the stratospheric flight Assessment of the performances at different altitudes (0..35 km, pressure mbar, temperature C) - Main Features: Atmospheric air as propellant Rechargeable, no on-board fuel = unlimited autonomy Page 4 of 19

5 S.C.R.A.T. WORKING PRINCIPLE The micro-compressors pressurize the first stage of the actuator The first valve regulates the air transfer to the second stage The second check valve regulates the thrust delivering The thrust delivered by the nozzle is measured by means of a torsional load cell Page 5 of 19

6 RX/BX SELECTION WORKSHOP 0,3 S.C.R.A.T. DESIGN DRIVERS 0,25 Varying parameters during simulations Volume stage 1 0,15 10 km Volume stage 2 0,1 PB 0,05 Diameter valve Diameter valve 29 8,5 9,5CGA 10 Δp open valve 1t [s] Δp open valve 2 0,25 F [N] F mean [N] Valves Peak Thrust CGA (Cold thetotal Impulse Gas Actuator), 0,1 together with a Dummy Actuator 0,031 Assembly (DAA) 0,023 Compressor pipe 2 stagebox) flangethe PB (Proximity Pitot tube0,020 0,3 0,2 1,12 max [N] OPTIMIZED VFALUES: 1 1 stage Two main Meanparts: thrust DAA 20 km 0,15 0,1 F [N] F [N] 0,2 0,01 Nozzle 0 km 5 km 10 km 15 km 20 km 25 km d [km] 0, ,5 9 t [s] 9,5 10 Page 6 of 19

7 PRELIMINARY DESIGN REVIEW S.C.R.A.T. FIRST EVOLUTION Flexural measure Transmission shaft Torsional measure Load cell Bushes Thrust measurement method Shaft design No-return valves Compressor 1 CGA 1st stage Compressor 2 Valves CGA 2nd stage Security valves Compressors in parallel Page 7 of 19

8 CRITICAL DESIGN REVIEW S.C.R.A.T. DEEP EVOLUTION only one cylindrical vessel (the CGA) outside the gondola shaft to sustain the CGA and transmit the torque Shaft Bearings housing Load cell Trasmission arm Supports Page 8 of 19

9 EXPERIMENT ACCEPTANCE REVIEW S.C.R.A.T. NEW DESIGN CGA on two angle brachets Electronic Boards Cabling Vessel Page 9 of 19

10 S.C.R.A.T. Experiment:

11 PROBLEM SOLVING APPROACH VALVES Compressed Air Pneumatic valve CGA 1st stage Prototype CGA 2nd stage Air flow Air flow Backup solution Air flow Page 11 of 19

12 PROBLEM SOLVING APPROACH THERMAL CONTROL Valves Bearings Compressors Page 12 of 19

13 INTEGRATION & LAUNCH

14 INTEGRATION & LAUNCH FLIGHT DATA Maximal Altitude: 24.5 km Flight Duration: 4h 30 min Environmental Data: -70 C, 25 floating ESRANGE, October 9th, 2010 S.C.R.A.T. DATA 101 Thrusts Recorded: Last Check 10-1 N (ground) & 10-4 Balloon ready for N (20 km)inflation

15 FLIGHT & DATA ANALYSIS 1. RAW SIGNAL EXAMINATION & PULSE IDENTIFICATION 2. FILTERING Low-Middle Troposphere LOAD CELL DYNAMICAL MODEL & TRANSFER FUNCTION ESTIMATION Upper Troposphere and Stratosphere I K Expected Thrust Simulation 3. DECONVOLUTION THRUST Measured Thrust& Simulation ESTIMATION a Damping c Damping c Electrovalve Activation Time s I /K Electrovalve Deactivation Page 15 of 19

16 RESULTS (1/2) Discrepancy between simulations and experimental data CFD simulations: pipes load effect Page 16 of 19

17 RESULTS (2/2) SCIENTIFIC RESULTS Thrusts between 10-1 N (ground) and 10-4 N (25 km) Total impulse in the range 10-2 Ns (ground) and 10-3 Ns (25 km) Respect standard CGA elaborating the same impulse, saving: 0.25 kg/h of propellant (15 km of altitude) 0.67 kg/h of propellant (<5 km of altitude) SECONDARY RESULTS: Atmospheric and density models Page 17 of 19

18 LESSONS LEARNED & CONCLUSIONS REXUS BEXUS PROGRAMME Possibility to participate to a real, little space mission! Hands-on Activity: from design to assembly & test to launch International Experts support TECHNICAL GROWTH Most important lesson: keep the experiment as simple as possible Learn scheduling and organization PERSONAL GROWTH "S.C.R.A.T. Tuesday evenings" Page 18 of 19

19 Thank you for your kind attention. Questions? Matteo Michele Giulio Lorenzo Leonardo Ruggero Marco I..I... Dal Cero San Bonifacio Federico Antonio Gabriele