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CanSat 2012 Critical Design Review

CanSat 2012 Critical Design Review. Team 2134 – IEEE UCSD. Presentation Outline. Introduction / Team Organization — Chris Warren Systems Overview — Chris Warren, Jeff Wurzbach Sensor Subsystem Design — Alex Forencich Descent Control Design — Chris Warren

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CanSat 2012 Critical Design Review

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  1. CanSat 2012Critical Design Review Team 2134 – IEEE UCSD CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  2. Presentation Outline Introduction / Team Organization— Chris Warren Systems Overview— Chris Warren, Jeff Wurzbach Sensor Subsystem Design— Alex Forencich Descent Control Design— Chris Warren Mechanical Subsystem Design— Jeff Wurzbach Communication and Data Handling Subsystem Design— Alex Forencich Electrical Power Subsystem Design— Alex Forencich Flight Software Design— Chris Warren, Alex Forencich Ground Control System Design— Chris Warren, Alex Forencich CanSat Integration and Test— Jeff Wurzbach Mission Operations & Analysis— Chris Warren Management— Chris Warren 2 Presenter: Chris Warren CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  3. Team Organization 3 Presenter: Chris Warren CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  4. Acronyms • AGL – Above Ground Level • BPS – Barometric Pressure Sensor • CAN – CanSat System • CAR – Carrier Subsystem • COTS—Commercial Off The Shelf • DCS – Descent Control System • IMU – Inertial Measurement System • LAN – Lander Subsystem • MCU – Microcontroller Unit • M&TE—Measurement and Test Equipment • PCBA – Printed Circuit Board Assembly • PCB—Printed Circuit Board • RTV – Room-temperature Vulcanizing Rubber • FSW – Flight Software • GSW – Ground Station Software • OTA – Over the Air • GCS –Ground Control Station • IEEE—Institute of Electrical and Electronics Engineers • UCSD, UC San Diego—University of California, San Diego 4 Presenter: Chris Warren CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  5. Systems Overview Chris Warren Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  6. Mission Summary • CanSat Objectives • Leave the Payload Envelope of the rocket • Separate into Carrier and Lander units at required altitude • Carrier Objectives • Maintain required descent rate • Record and send telemetry data to ground • Lander Objectives • Maintain required descent rate • Record telemetry data • Land a large grade A hen's egg safely • Selectable Objective • Measure and store impact force data at a sampling rate of 100 Hz • External Objectives • We wish to release as much open-source data, programming, and other system information as possible • We will publish information and experimental findings that proved to be important and useful in our project • We have also turned our CanSat project into an Independent Study/Senior Design project for class credit • This class structure will force us to remain on schedule • It will also more approximate the administrative processes of a aerospace project 6 Presenters: Chris Warren Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  7. Summary of Changes Since PDR • Since PDR, our most important change has been a redesign of the Carrier and Lander modules • Shape has been changed from circular to a more rectangular geometry • Carrier / Lander interface changed from a stacked design to a nested arrangement • We have also revised our descent control strategy • Now using staged hemispherical parachutes • Descent rates more accurately calculated / predicted • Communications, Data Handling, Flight Software, and Ground Control Systems are essentially unchanged Presenters: Chris Warren Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  8. System Requirements – Cansat Mission 8 Presenters: Chris Warren Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  9. System Requirements – Cansat Mission (cont’d.) 9 Presenters: Chris Warren Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  10. System Requirements – Carrier 10 Presenters: Chris Warren Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  11. System Requirements – Lander 11 Presenters: Chris Warren Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  12. System Concept of Operations – Pre-Launch Activities • Arrival in Texas • Team checks all hardware, support systems, etc. for damage during travel • Final touches are made • Team attends Safety Checkout and Briefing • Launch Day • Team checks in at field • Mass and fit checks are made • Final launch preparations are completed • Team has briefing on flight operations, team members assume assigned mission positions • Flight window is requested by Mission Control Officer Presenters: Chris Warren Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  13. System Concept of Operations – Launch Activities • Mission Control Officer checks with the Ground Station and Cansat Loading Crews to make sure everything is go for launch • When ready, the MCO allows for the launch to proceed • During the demonstration flight, the CanSat goes through its assigned mission profiles—relaying data, controlling descent speed, and landing safely • The team stands by, watching all received flight data for anomalies, and waits for the Carrier and Lander to touch back down Presenters: Chris Warren Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  14. System Concept of Operations – Post-Launch Activities • Once Carrier and Lander are confirmed as landed back on the ground, the Mission Control Officer will notify the flight coordinator that we are ready to recover • Mission Control Officer will then send out the Recovery Crew members to recover the flight hardware • Only after given an all-clear signal by the flight coordinator • Received telemetry data is first archived for backup purposes, and then used as a guide for the recovery efforts • The Recovery Crew will locate the flight hardware, and ensure score cards have been filled out correctly before returning to the launch pad area • Once back to the ground station location, we will upload all onboard data, and begin preparations for the Post-Flight Review Presentation Presenters: Chris Warren Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  15. Physical Layout DCS Carrier GPS Lander Sleeve (part of Carrier’s Frame) Carrier Electronics Carrier IMU Antenna (1 of 2) Carrier Radio 152mm Wilkinson Power Divider PCB Lander Release Servo 121mm Lander (inside Carrier) Presenters: Chris Warren Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  16. Physical Layout-Launch Configuration Presenters: Chris Warren Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  17. Physical Layout-Carrier (with Lander) • Carrier model mass: 359g • Items not modeled: • Cables • Connectors • DCS components Carrier 1st Stage DCS Compartment Carrier 2nd Stage DCS Compartment Lander Sleeve Carrier Electronics Release Servo Carrier GPS Antennae Presenters: Chris Warren Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  18. Physical Layout-Lander • Cutaway view of the lander • Parachute mounted to the lid via the 4-40 standoffs holding the electronics in. • Elastic straps interface to the shroud lines of the parachute to the 4-40 threads Batteries Lander GPS Radio IMU 106mm Foam Egg 81.3mm Antennae Presenters: Chris Warren Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  19. Physical Layout-Lander • Lander model mass: 296g • Items not modeled: • Cables • Connectors • DCS components Presenters: Chris Warren Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  20. Launch Vehicle Compatibility • CanSat (Carrier + Lander) will be inserted into the payload envelope upside-down, with the initial drag chute closest to the base of the rocket stack • This allows the CanSat to fall out in the proper orientation • The CanSatdimesions will be within the required envelope, and will have a factor of safety built in such that the CanSat will fall out smoothly • 120.65mm (4.75in) • 152.00mm (5.98in) • We have ordered and received a LOC/Precision Minie-Magg rocket body • We will use this prior to our flight to ensure proper CanSat – Rocket integration and fit Presenters: Chris Warren Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  21. Launch Vehicle Compatibility • Include a dimensioned drawing that shows clearances with the payload section • Focus on launch configuration (carrier + lander) • Include all descent control apparatus • At CDR this should include measured and/or prototype dimensions 152mm 25.4mm DCS allowance Presenters: Chris Warren Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  22. Launch Vehicle Compatibility (cont’d) • Include a dimensioned drawing that shows clearances with the payload section • Focus on launch configuration (carrier + lander) • Include all descent control apparatus • At CDR this should include measured and/or prototype dimensions Reference Envelope Plug to be removed 4.75” Cansat Presenters: Chris Warren Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  23. Sensor Subsystem Design Alex Forencich CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  24. Sensor Subsystem Overview Presenter: Alex Forencich CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  25. Sensor Subsystem Requirements Presenter: Alex Forencich CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  26. Sensor Changes Since PDR • No major sensor changes • Prototype for communications subsystem includes GPS module • Successfully placed GPS in 10 Hz binary mode • Successfully parsing and forwarding GPS data packets • Successfully decoding GPS packets in GSW • Procured Mongoose IMU board for firmware development • Gyroscope and accelerometer working • IMU properly communicates in packet mode to main MCU for logging and data relay to ground station • Pressure sensor driver in progress • Sensor sampling and packetization code in progress Presenter: Alex Forencich CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  27. Carrier GPS Summary • Selection: MT3329 • 66 channels, 2.4 m accuracy, 6 g mass, 10 Hz update rate • 3.3 volts, 42 mA power requirement (max during tracking) • -165 dBm tracking • Extremely compact and lightweight • Internal antenna • High update rate • Binary protocol support for efficientstorage and transmission of GPS datawith no reprocessing Presenter: Alex Forencich CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  28. Carrier GPS Summary • Custom binary protocol • Much more efficient than NMEA • Does not require parsing and filtering • Encapsulated in radio communications packet verbatim with preamble, length, and checksum stripped • 32 data bytes per packet Presenter: Alex Forencich CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  29. Carrier Non-GPS Altitude Sensor Summary • Selection: BMP085 • 20 – 110 kPa range, ±100 Pa accuracy, 0.09 g mass • 3.3 V, 5 µA power requirement, I2C interface • Extremely compact and lightweight • Very accurate • Built in pressure sensor • Included in Mongoose IMU board • Calculating pressure requires reading calibration data along with raw temperature and pressure data, then following an algorithm specified in the datasheet • Converting pressure to altitude is performed with the equation: • Zero reference will be providedby identical sensor in GSW Presenter: Alex Forencich CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  30. Carrier Air Temperature Summary • Selection: BMP085 • 20 – 110 kPa range, ±100 Pa accuracy, 0.09 g mass • 3.3 V, 5 µA power requirement, I2C interface • Extremely compact and lightweight • Very accurate • Built in pressure sensor • Included in Mongoose IMU board • Pressure sensor includes temperature sensor for temperature compensation • Using the internal sensor requires no extra components and no additional calculation as the temperature must be calculated during the derivation of pressure • Temperature resolution 0.1 ºC, accuracy ±1.0 ºC over 0 – 65 ºC Presenter: Alex Forencich CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  31. Lander Altitude Sensor Summary • Selection: BMP085 • 20 – 110 kPa range, ±100 Pa accuracy, 0.09 g mass • 3.3 V, 5 µA power requirement, I2C interface • Extremely compact and lightweight • Very accurate • Built in pressure sensor • Included in Mongoose IMU board • Calculating pressure requires reading calibration data along with raw temperature and pressure data, then following an algorithm specified in the datasheet • Converting pressure to altitude is performed with the equation: • Zero reference will be providedby identical sensor in GS Presenter: Alex Forencich CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  32. Lander Impact Force Sensor Summary • Selection: ADXL345 • ±2/4/8/16 g range, 4 mg/LSB resolution, 3200 Hz max update rate • 3.3 V, 40µA/0.1µA (active/standby) power consumption • Configurable update rate and bandwidth • Extremely compact and lightweight • Low power consumption • Very accurate • Included in Mongoose IMU board Presenter: Alex Forencich CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  33. Descent Control Design Chris Warren CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  34. Descent Control Overview • Carrier and Lander descent control will be accomplished with hemispherical parachutes. • Two parachutes will be attached to the Carrier for control of entire CanSat assembly descent • First parachute jettisoned before second deploys • One parachute will be attached to the Lander for the control of its own descent rate after separation • Rip-stop Nylon fabric will be used cut into gores and stitched into the chosen hemispherical geometry. • Material chosen due to its COTS nature and proven use • Nylon cords will be used for suspension lines • Suspension lines must remain strong to avoid failure Presenter: Chris Warren CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  35. Descent Control Changes Since PDR • We have chosen to work with a hemispherical parachute design • More stable than last year’s choice of a simple parasheet • While more difficult to manufacture, this labor cost will ideally be offset by great gains in reliability and predictability of our descent control system • At PDR, we were unsure of the main mechanical design, and therefore did not have a firm idea where to progress with the DCS • We now have a better mechanical model, and therefore have chosen the descent control strategy that best works with our overall design Presenter: Chris Warren CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  36. Descent Control Requirements Presenter: Chris Warren CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  37. Carrier Descent Control Hardware Summary • Carrier DCS will be governed by the data received by the onboard pressure altitude sensor • Flight software will poll the altitude sensor, and deploy the parachutes at the appropriate heights • Deployment is actuated by a servo-controlled containing lid • Jettison of first chute controlled by solenoid • Testing possible by overriding the flight software to enter the parachute deployment phases with commands from the GCS Presenter: Chris Warren CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  38. Carrier Descent Control Hardware Summary • There will be two parachutes, one for each required descent rate • The first parachute will be a hemispherical parachute with a opening diameter of 35 centimeters • The second parachute will be a similar hemispherical parachute with a diameter of 75 centimeters • Both carrier parachutes will be manufactured from neon orange rip-stop nylon Presenter: Chris Warren CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  39. Carrier Descent Control Hardware Summary • The Pressure Altitude Sensor is accurate from 20 to 100 kPa • Sensor outputs raw binary data that must be run through a formula to generate accurate pressure readings • Data will be processed by the flight software and onboard microcontrollers • See Sensors section for more detail • Actuator is a simple servo • Controlled by a pulse-width modulated signal • Easily generated by the microcontollers onboard Presenter: Chris Warren CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  40. Lander Descent Control Hardware Summary • Lander DCS will be governed by the data received by the onboard pressure altitude sensor • Flight software will poll the altitude sensor, and deploy the parachutes at the appropriate heights • Deployment is actuated by a dragline connected to the carrier • Testing possible by overriding the flight software to enter the carrier/lander separation phase with commands from the GCS • There will be one parachute • The parachute will be a hemispherical parachute with a opening diameter of 75 centimeters • It will be manufactured from neon pink rip-stop nylon Presenter: Chris Warren CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  41. Lander Descent Control Hardware Summary • The Pressure Altitude Sensor is accurate from 20 to 100 kPa • Sensor outputs raw binary data that must be run through a formula to generate accurate pressure readings • Data will be processed by the flight software and onboard microcontrollers • Actuator is the carrier/lander separation mechanism • Dragline is a nylon line connected to the carrier • As lander falls away, the line deploys the lander’s parachute • For a thorough discussion of the separation actuation, see the Mechanical Subsystem section Presenter: Chris Warren CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  42. Descent Rate Estimates Presenter: Chris Warren CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  43. Descent Rate Estimates • This allows for estimation of descent rates for various system configurations Presenter: Chris Warren CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  44. Mechanical Subsystem Design Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  45. Mechanical Subsystem Overview • Carrier • Two aluminum disks separated with an acrylic frame that accommodates the lander • Servos are used to actuate the Lander release and second phase DCS release. • 4-40 hardware used to mount all electronics • Antennae mounted to brackets glued to the side of the lander sleeve. • Lander • Frame made of Acrylic • Egg Protection done with expanding foam, precast to fit the body of the lander with the shape of an egg cast into it • Electronics mounted with 4-40 hardware. Wilkinson PCB and antennae cast into upper foam piece, with cabling • Lower piece of foam is cast to the bottom lid, which is attached to the frame with screws. Presenter: Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  46. Mechanical Subsystem Changes Since PDR • Hit roadblock with stacked design presented at PDR • Main roadblocks • Reliable DCS deployment • Large number of complex parts • Changed design to a coaxial configuration • Lander and Carrier share the same central axis • Changed release mechanism from rotary solenoid to servo based. • Added accurate CAD model for Wilkinson Power Divider PCB. • Improved margin for Cansat to Launch vehicle interface Presenter: Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  47. Mechanical Subsystem Requirements 47 Presenter: Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  48. Lander Egg Protection Overview • Egg protected by 2 pieces of expanding foam, pre-formed to the general shape of the egg. • Upper piece molded into the Lander Body. • Lower pieced molded onto the Lander’s Underside cover • Lander’s Underside Cover will be held to the Lander with screws. Presenter: Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  49. Mechanical Layout of Components DCS Carrier GPS Lander Sleeve (part of Carrier’s Frame) Carrier Electronics Carrier IMU Antenna (1 of 2) Carrier Radio 152mm Wilkinson Power Divider PCB Lander Release Servo 121mm Lander (inside Carrier) Presenters: Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

  50. Material Selections • 3003 Aluminum sheet metal • Easy to work with (machines easily, takes bends well) • Readily available (carried by Home Depot and other local vendors) • Good strength to weight ratio • 40 mil High Impact Polystyrene • Vacuum formable • Allows low weight non-structural and low strength parts to be made • Low density foam • Low weight • Easily custom formable • Readily available • Acrylic Sheet • LaserCamm compatible • Glues easily • Takes threading operations • Low weight • Readily available from local sources Presenter: Jeff Wurzbach CanSat 2012 CDR: Team 2134 (IEEE UCSD)

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