2013 RockSat-C Preliminary Design Review

Transcription

1 2013 RockSat-C Preliminary Design Review TEC (The Electronics Club) Eastern Shore Community College Melfa, VA Larry Brantley, Andrew Carlton, Chase Riley, Nygel Meece, Robert Williams Date 10/26/2012

2 Mission Overview The inspiration for our project originates from our team leader s participation in the 2012 RockOn workshop. During the interval between the launch and delivery of the returned payload, it would be beneficial to simply glance at a smartphone and observe real-time data indicating current position and status of the experiment. The primary objective is to demonstrate an inexpensive system for the rapid dissemination of flight data through the use of an APRS (automatic packet reporting system) transmitter on the payload. Our plan B, if legal or logistical obstacles prevent including a payload that emits RF energy, is a passive system to collect and record APRS packets from terrestrial sources and measure reception characteristics of other earth based radio systems.

3 Mission Overview Secondary objectives include: Observing the performance of COTS (commercial off the shelf) radio sub-systems under suborbital flight conditions Developing baselines for expected radio wave propagation to and from the launch trajectory Gaining knowledge of appropriate APRS configuration settings for a system that has an antenna height that ranges from sea level to seventy miles without flooding and overloading the network when transmitting from high altitudes

4 Mission Overview Concepts and Theory We expect to prove that an inexpensive system can be used to provide telemetry from a suborbital vehicle. We expect to prove that Doppler shift and spin modulation of terrestrial signals received from a suborbital vehicle can be correlated to flight data: Using the Doppler shift of a terrestrial commercial broadcast FM signal received by our payload to relative velocity Using variations in received signal strength caused by rotation of the antenna radiation patter to determine spin rate We expect to prove that COTS radio subsystems can survive the rigors of a rocket launch and perform at suborbital altitudes. The mission will be deemed a success if any new data is gathered that can aid in the development of future projects.

5 Previous Research An internet search revealed that in 2000, SOCEM (Sub-Orbital CubeSat Experimental Mission) was a successful endeavor by Kentucky Space, in coordination with the NASA SRPO (Sounding Rocket Program Office) at NASA Wallops and California Polytechnic State University (Cal Poly), to demonstrate a new platform for high-risk, sub-orbital, fast access to space for small payloads.

6 Previous Research Our action plan includes attempting to locate and contact participants from the SOCEM mission and discuss the lessons learned and how we might apply them to a mission using an APRS network that has experienced over a decade of growth.

7 Previous Research Similar projects have flown on high altitude balloons. Studying the results of these experiments may be helpful, but the dynamics of a balloon launch and a suborbital flight are different and will need to be considered. The US Naval Academy has experimented with APRS transmitters aboard both balloons and ocean buoys. It is theorized that the propagation characteristics after splashdown may be similar to transmitting from a buoy.

8 Mission Overview: Concept of Operations Throughout the duration of the flight our payload will activate its various systems, record data, and transmit an APRS packet containing location coordinates and other possible flight data.

9 Flight Plan Altitude t 1.7 min Altitude: 95 km t 1.3 min Altitude: 75 km Acquire gps signal Apogee t 2.8 min Altitude: 115 km End of Orion Burn t 0.6 min Altitude: 52 km t 4.0 min Altitude: 95 km t 4.5 min Altitude: 75 km t 5.5 min Chute Deploys t = 0 min -G switch triggered -All systems on -Begin data collection t 15 min Splash Down

10 Block diagram if separate antennae are available

11 lock diagram if limited to ingle broadband antenna

12 Required Hardware Broadcast/Receive Transmitter Microcontroller (Arduino) GPS Batteries and switches Repurposed RockOn board

13 System Level Block Diagram Plan A Plan B 13

14 System Design Physical Model FM Receiver Batteries GPS Reciever Audrino RockOn Board 14

15 System Concept of Operations 15

16 RockSat Payload Canister User Guide Compliance Mass, Volume To be negotiated. Current estimation 50 percent of mass, 50 percent of volume Payload activation G-switch activation from the repurposed RockOn board RockOn board will act as a master controller for the remainder of the payload The g-switch is a micro switch weighted appropriately to trigger on launch Rocket Interface Shorting wires

17 Management

18 Budget earnest deposit COSGC 1000 ESCC departmental budget 2000 balance due COSGC 4000 AACC MentorLinks grant 4000 project hardware 2135 Tech Club budget 400 gps receiver 200 ESCC in kind not itemized: broadcast receiver 80 facilities, telecommunications, arduino w/ proto shields 250 faculty advisor workload, duplexers 175 incidental supplies APRS transmitter 300 misc electronic components 150 fabrication hardware 50 consumable chemicals and materials 50 wire and terminations 50 spare key items 830 food/travel/lodging/amenities for team members 1000 Total projected cost 7135 Committed resources 6400 Projected need for additional support 735

19 Issues and Concerns Determining all compliance requirements Defining spacecraft in terms of ITU and FCC requirements Selecting transmit frequency to meet guidelines of Wallops Flight Facility and all government agencies and to not inconvenience users of other radio services

20 Issues and Concerns Ability of COTS GPS receivers to resolve position at high altitudes Requires careful scrutiny of manufacturers specifications before making selection Time from power-on to acquisition of satellites for COTS GPS receivers. Early flight position will not be recorded Requires careful scrutiny of manufacturers specifications before making selection

21 Issues and Concerns Selecting transmitter output power that will: Allow battery life to extend well beyond the duration of flight Provide an acceptable RF link budget to an internet gateway receiver from sea level Not flood the APRS network when transmitting from high altitude by reaching many gateway receivers (this may end up being a packet configuration issue or frequency selection issue more than output power)

22 Issues and Concerns Working with NASA very early in the design process to determine available antenna port specifications So that performance testing closely models flight performance So that we may refine the payload design to match available antenna specifications

23 Conclusions To have successfully to demonstrated an inexpensive system for the rapid dissemination of flight data through the use of an APRS (automatic packet reporting system) transmitter on the payload. We are ready to make detailed drawings with exact dimensions and circuit schematics. We are prepared to make final component selections and begin testing. We need to finalize plans for can usage and how we can partner with another team.