1. 1 University of Maryland DYMAFLEX SHOT II Pre-Flight Presentation June 29, 2012

2. 2 Test of DYMAFLEX low rate communications system Verify link margins on a balloon flight Verify packet reception with a similar link margin Determine actual packet loss percentage with satellite link margin Verify custom packet checking scheme Validate preliminary satellite software Confirms theoretical link calculations for satellite in the desired orbit Proves functional hardware for satellite use Highlights any issues with radio hardware or C&DH Mission Overview

3. 3 Balloon flight test of satellite radios Will help gather data to determine if these radios, which are intended for use in the satellite, are a reasonable option Initial tests of satellite flight software Contains same C&DH components as satellite and first revision of software intended for use on the satellite DYMAFLEX Connection

4. 4 Payload Block Diagrams

5. 5 Mechanical: White foamcore poster board, folded with angle cuts for structural integrity Tube attachment with washers and paper clips for holding in place Insulating foam used to keep components in place and for thermal purposes RF: Receiver, Transmitter, TNC, Splitter/Combiner TNC: Kantronics KPC9612 XCTR: Hamtronics T304 RCVR: Hamtronics R303 Inside shielded box internal to the main structure 4 dipole antennas, 2 for receive, 2 for transmit UHF: 435.15 Mhz Balloon Payload EIRP: 0.37W Link Margin: 7.00 dB VHF: 145.89 Mhz Link Margin: 8.38 dB Payload Design: Mechanical and RF Info.aprs.net

6. 6 Payload Design: C&DH dsPIC33FJ256GP710A – the flight computer breakout which will be used in flatsat testing Thermister Canbus transciever for future DYMAFLEX testing SD card for logging received packets 32.768kHZ crystal for accurate timekeeping

7. 7 Payload Design: Software Follows same pattern as final flight computer Three independent non- blocking processes Groundstation handler Sensor handler Satellite handler Currently lacks some satellite fail-safes Only one interrupt driven process

8. 8 Bench testing between satellite and ground station C&DH and COMM systems integrated No packets lost during testing Serial functionality between COMM and C&DH has no issues Software working as expected Transmission tested from satellite to ground station Uplink from ground station to satellite not yet tested Sensors on C&DH record reasonable data: 76° F measured room temperature, packet count accurate, RTC count accurate Test Data

9. 9 On board logging of all data All raw packets All packet data (packet count, commands received, retries made) Ground station logging of all data All raw packets Packets received and packet count versus the packet number in the received packet Dropped packet percentage will play a key role in determining the viability of the radios and the robustness of the packet checking scheme Packet information Temperature, time C&DH has been active, current satellite mode, number of packets sent so far Expect minimal packet loss and that the radios will be determined adequate for the satellite needs in this simulated environment testing Flight Expectations

10. 10 Demo: Satellite typical status packet Satellite sends and logs packet Ground station receives and logs packet successfully View interior and exterior of payload Payload Demonstration