Pulsed Plasma Thruster Propulsion System

Transcription

1 Pulsed Plasma Thruster Propulsion System Final Presentation May 4, 2006 BalloonSAT Missions to the Edge of Space Team MASA Eric Solanyk Chandra Kunapuli Kelly Loving Jason Farmer Nicholas Mosely

2 Mission To design, test, and construct a propulsion system using a pulsed plasma thruster Propulsion system will be flown onboard a BalloonSAT and tested at the edge of space Mission objective is to find out how the propulsion system works and test it in a space environment

3 Mission Requirements Take pictures of both the balloon and the earth Gather interior and exterior temperature data Gather humidity data Support all systems with the structure Must support launch, flight, and landing environments Must support all other components Gather ascent and descent rates Total weight cannot exceed 750 grams Total cost cannot exceed $300

4 Overview of Plasma Propulsion Completely self-contained satellite propulsion system Employs solid Teflon as propellant High voltage causes arcing across the face of the propellant Forms a plasma Plasma accelerated by electromagnetic force Generates relatively low thrust Is only practical on satellite systems Applications are currently in use and being developed by USAF

5 Design Power supply generates electric pulse High voltage and low current Generated by a voltage increasing circuit Pulse is divided into anode and cathode The pulse is discharged across the face of solid Teflon The discharge is activated by a BASIC stamp (programmable microcontroller) Discharge causes an ablation of Teflon plasma Plasma acceleration generates thrust

6 Thruster Design Cathode + Thrust Direction High Voltage Source Current Flow Anode - Teflon Ablated Teflon (plasma)

7 System Diagram Power (Three 9 volt batteries) Power (three 12 volt batteries) Switch Switch Heater Timing Circuit Camera 1.5 Volt Battery Switch Hobo (internal battery) Basic Stamp Relay Humidity Sensor Outside Temperature Internal Temperature Kodak Flash Circuit Teflon Pulse Plasma Thruster

8 System Organization

9 Dimensional Drawing

10 System Drawing

11 Safety Concerns Coronal discharge High Voltage Precautions Copper tube will be insulated from the rest of the satellite to defend against possible coronal discharge Entire propulsion system will be insulated against the electrical current Corona dope used as insulation (can protect up to 3500 volts) BASIC Stamp controls thruster at all times Thruster cannot fire on its own

12 Mass Budget Item Teflon Weight (g) Foamcore Camera 9V Connectors Copper Wire Timing Circuit + Batteries Plasma Capacitor System Switch Piece of Foam Hobo Temperature Guage Tape Mirror 29.7 BASIC Stamp 9.07 Capacitor 75.6 Relay component 20 HOBO Heater Subtotal the remainder of weight = 69.2

13 Financial Budget Our final cost total came to $ We were $98.45 under-budget

14 Data Collection Propellant will be weighed before and after flight to determine amount of Teflon ablated Propellant will be examined for burn marks

15 Organizational Chart Jason Eric Kelly Nick Chandra Thruster Team Lead Structure Electrical Overview Management Budget Design Drawings Testing

16 Expected Results Thruster to fire 90 minutes into flight Internal temperature to approach but not reach 0 degrees C External temperature to approach -60 degrees C at the flight s zenith Camera to capture both earth and balloon

17 Launch Launch took place on April 22, 2006 in Windsor, Colorado

18 Ascent/Descent Rates The balloon ascended at m/min The balloon descended at m/min We got these numbers from the Edge of Space sciences website

19 Pictures The camera took pictures every 3 minutes throughout the flight Problems with exposure and focus limited the quality of the images The satellite had a mirror system on board to take photos of both the balloon and the earth view looking up view of the horizon

20 Results Due to a switch failure thruster system was never activated Switch was stuck on the off position Force placed on the switch during attempted activation punctured the BalloonSAT, causing a fault in the insulation against the outside environment

21 Internal Temperature Plot

22 External Temperature Plot

23 Humidity Plot

24 Results and Analysis Internal temperature dropped below 0 degrees C due to the punctured structure During testing, internal temperature stayed above 0 degrees C External temperature data matched the expected results The data is very noisy, due to a faulty external temperature sensor Humidity data matched expected results

25 Conclusions A switch failure caused the thruster system to fail The switch failure also caused the internal temperature to drop below 0 degrees C The structure, camera, heater, and HOBO systems worked as designed

26 Lessons Learned Be thorough in design it will save time during the construction Allow more time for construction and design changes Test and retest every part of every system Communication between team members is key

27 Advice for Future Classes Don t procrastinate Get to know Tim May (electronics man) Get outside help Communicate with your teammates in everything Test and retest Make sure you are having fun