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RocketSat 8 Preliminary Design Review

RocketSat 8 Preliminary Design Review. University of Colorado Boulder 10/26/11. Nomenclature. RODEO – Roll Out De-Orbiting Device VACA - Validation Assembly of Communication Antennae DONDE – Attitude Determination System. Mission Statement.

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RocketSat 8 Preliminary Design Review

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  1. RocketSat 8 Preliminary Design Review University of Colorado Boulder 10/26/11

  2. Nomenclature • RODEO – Roll Out De-Orbiting Device • VACA - Validation Assembly of Communication Antennae • DONDE – Attitude Determination System

  3. Mission Statement • To design a system that deploys the Roll Out De-Orbiting Device (RODEO) developed by Composite Technology Development (CTD). This shall provide a possible means to de-orbit future small satellites. • To eject VACA for the examination of communication capabilities between two differently located antennas. • To validate the Attitude Determination System (ADS) developed for RockSatC.

  4. Theory and Background • The aerospace market has been continually moving towards small satellites • Approximately 23 small satellites (10kg-500kg) are launched every year by the United States alone • The continual growth of small satellites in space increases the likelihood of collisions exponentially • The rise in number of satellites in orbit has led to an increasing need for a cost effective and lightweight means to de-orbit small satellites.

  5. Theory and Background Continued • Communication distance and capability is often increased by having line of sight between a transmitter and receiver. • DONDE was a small, low-cost system designed by RocketSat VII to determine the orientation of the payload through a CMOS optical sensor and other various devices.

  6. Mission Overview: Concept of Operations Collect Data from VACA Apogee Altitude: ≈160 km Deploy RODEO Deploy VACA Launch Begin Telemetry End of Orion Burn Chute Deploys Power off all systems Pre-Launch -G switch triggered -All systems on -Begin data collection -Initialize Cameras Splash Down

  7. Mission overview: Expected Results • We expect that the RODEO system be extended whilst attached to the rocket • We expect to capture images and video of the extended RODEO system • We expect the VACA to be deployed from the main plate • We expect to measure signal quality between the antennae • We expect the signal quality of the antenna on the RODEO to be stronger than the one on the main plate • We expect to validate the attitude determined by DONDE

  8. Main System Overview

  9. Main SystemFunctions • Houses other subsystems • Deploys RODEO • Validates RODEO • Ejects VACA • Processes Communication with VACA

  10. Requirements

  11. Requirements (cont.)

  12. Structures Overview

  13. Basic Design Overview Single middle plate design: the RODEO, the cube sat (VACA) and its ejection system are mounted on the bottom of the middle plate. The ADS and electronic boards will be on top of the middle plate incased in an air tight shell with a view port for the camera. Front View A- air tight shell B- Cube Sat & ejection system C- RODEO D- Camera Bottom View B- Cube Sat & ejection system C- RODEO D- Cameras A C D B D E C D D Top View (without airtight shell) D- ADS E- electronics board B

  14. Design

  15. Structural Requirements

  16. Structural Requirements

  17. Trade Study for Stack Mounting

  18. Stack Mounting • It has been decided to use the middle mount offered by Wallops. • A middle mount will separate the two systems into airtight and open to space • Open air hardware will be interfaced to electronics boards via a sealed electrical feedthrough • The mount will also make sure the deployable is not in the field of view of the camera. • The top and bottom mounts either connect to the top or bottom, not both. • This is due to other projects being on either side of our stack

  19. Preliminary Mass Budget

  20. Preliminary Testing • Thermal analysis on metal components will be done to ensure hardware is safe upon reentry. • SolidWorks Analysis • Our SolidWorks model will undergo structural testing in the SolidWorks program. • SimulationXpress analysis will be used for load testing as well as testing the torque of the design • This will also be used to determine the precise locations of sensors for the best field of view. • Stress analysis in SolidWorkswill show how forces on our model will be distributed.

  21. Risk Analysisfor Structural Failiures

  22. Current Progress and Goals Current Progress • Current design in SolidWorks of the main plate. • Research and decide type of ejection system (spring). Goals • Complete Solidworks stress analysis on each of our plate materials • Complete torque testing on the stack • Complete torque spec for materials to be used • Identify points of failure for mechanical model • Complete thermal analysis at reentry and electronics protection • Make more detailed designs in relation to updated system requirements • Researching materials to be implemented for stack • Assessing materials and parts to be ordered

  23. Electrical System Overview

  24. Functions • Deploy RODEO using timed event • Image RODEO with HD and low resolution cameras • Communicate with VACA using RF • Process images and data • Store images, and data in on-board memory • Send data and low resolution images through telemetry lines

  25. RODEO Electrical System from RockSat power Power Converters RF chip Antenna 1 Memory MCU RF Comm to CubeSat Imaging HD Camera RODEO release to telem Antenna 2 FPGA Lo-Res Camera

  26. Main System Power • Power for the main plate shall be delivered by 28 V lines from the rocket • Total power consumption for the mission shall not exceed the limit of 1 A/hr • 28 Volt power shall be reduced to 9 Volt power for distribution to subsystems • Filtering techniques shall be employed to reduce noise on power lines for reduction of errors in signal transmission

  27. Power Distribution Diagram 28V Buck Converter 9V Linear Regulators ADS Main System MCU COMM RODEO

  28. Main Power Requirements Total Power Required from 28V lines ≈ 6.22 W

  29. DC to DC Conversion • 28V power will be reduced to 9V power through the use of switched mode converter for decreased power losses • DC conversion for microcontroller and other electronics components will be performed using linear regulators

  30. Electrical Component Selection • We will be selecting components to use in the electrical system based on performance requirements and ease of interface with other components. • Primary hardware considerations: • Low power consumption • Accommodate interface protocols employed • Withstand launch, reentry conditions

  31. Electrical Component Selection Microcontroller • Requirements: • Interface with RF CommSystem • Process data (sent via RF Comm) • Store data to memory • Upload data to telemetry lines

  32. Electrical Component Selection • We chose the XMEGA256A3 microprocessor. • Same one used on last year’s system: driver software already written, tested, and proven • Capable of interfacing with XBEE RF protocol

  33. Electrical Component Selection Memory • Requirements: • Non-volatile storage • Sufficiently fast write speed • Easily interfaced to microcontroller • Heat, vibrations resistent

  34. Electrical Component Selection • We decided to use digital (SD) cards • Cheap, compact, reliable data storage • Non-volatile • Many available software libraries • Light-weight and durable

  35. Electrical Component Selection Cameras: • Provide visual confirmation of RODEO deploy • One low-resolution camera • Images processed on-board, sent to telemetry lines • Same camera as in VACA • One high-resolution camera • Data saved straight to internal memory card • Hardware implementation: GoPro HD Hero2 Outdoor Edition

  36. Electrical Component Selection HD Camera Selection:

  37. System Software Overview

  38. Software Overview • Software for the main microcontroller will control all other non-deployable components of the mainsystem • Software will run efficiently and at a speed that will record and store all data • Software will be programed as a state machine • Software will be redundant in order to prevent failures moving from state to state • Redundancies include watchdog timers and secondary signaling hardware to confirm timed events

  39. Main Plate State Diagram Off -Check State Power Failure User Power Pre-Launch -Power Main MCU -Signal HD Camera -Signal ADS MCU -Power Low Res Camera -Start transmitting data through telem lines Deploy -Initialize mechatronics to deploy VACA Timed Event/ Watchdog Timer Watchdog Time/ Timed Event Timed Event/ G Switch Apogee -Signal VACA -Deploy RODEO Launch -Start Watchdog Timer

  40. Language Trade Study

  41. Software Concerns • How to design the code for power failure survival • How to check the health system of the payload throughout mission • How to mange component level failures • How to make code more robust and redundant • How to best integrate software functionality with hardware

  42. Subsystem A: RODEO Courtesy of CTD

  43. Subsystem: RODEO • RODEO is a drag inducing deployable boom developed by CTD for the deorbit of small satellites • System shall electromechanically deploy RODEO device and validate deployment with deployment sensors and photo evidence • HD video of the RODEO device will be recorded • A low resolution camera will capture images of the RODEO device and transmit data to ground via the telemetry lines • The RODEO boom shall additionally house an antenna to increase communication quality with VACA

  44. Structures: RODEO • Rodeo shall be securely held in place on the bottom of the middle mount plate • Rodeo will be mounted at the edge of the keep out zone so that sail deploys outside of rocket

  45. Structures: RODEO Undeployed RODEO Two camera angles -one HD camera -one low resolution camera Deployed RODEO -three foot sail when fully extended

  46. RODEO Release Mechanism • The RODEO is stored under potential within an aluminum structure • The RODEO is contained with hinged door • The release of the hinged door produces an extension of the rodeo sail in less than 1 second

  47. RODEO Release Mechanism Continued • The release of the RODEO containment door will be executed using an electro-mechanical device • The electro-mechanical device will be have sufficient holding torque for launch survival • Testing will be done to ensure survivability and properly timed release of RODEO

  48. Rodeo Release Mechanism Continued • Possible Release Mechanisms • Frangibolt • Linear Actuator • Burn Wire • Release Mechanism Characteristics • Launch survivability • Size and weight constraints • Ease of integration with RODEO • Ease of electrical interfacing • Cost Courtesy of Wikipedia Courtesy of Tiniaerospace

  49. RODEO Electrical Interface • A timer-controller power line will switch to high voltage at the time that we will want the RODEO to deploy. • The signal will trigger power to be sent to the release latch

  50. VACA

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