1 / 104

Formation Flying

Formation Flying. Rachel Winters Matt Whitten Kyle Tholen Matt Mueller Shelby Sullivan Eric Weber Shunsuke Hirayama Tsutomu Hasegawa Aziatun Burhan Masao Shimada Tomo Sugano. Motivation. Can enable baseline to form large instruments in space Escort Flights

melva
Download Presentation

Formation Flying

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Formation Flying Rachel Winters Matt Whitten Kyle Tholen Matt Mueller Shelby Sullivan Eric Weber Shunsuke Hirayama Tsutomu Hasegawa Aziatun Burhan Masao Shimada Tomo Sugano

  2. Motivation • Can enable baseline to form large instruments in space • Escort Flights • Provide detection/protection from threats • Provide visual inspection for damage

  3. Design • A satellite that will fly escort to the space shuttle • Satellite provides visual inspection of shuttle exterior for 24 hour period of time • Satellite will be transported into space on shuttle • Satellite must meet University Nanosat requirements

  4. Systems Integration & Management Rachel Winters, Matt Whitten • Expendable vs Recoverable spacecraft (90%) • Recovery method designed (80%) • Determine shuttle-interface requirements (100%)

  5. Relative Orbit Control & Navigation Kyle Tholen, Matt Mueller • Determine relative orbit to meet mission requirements (90%) • Determine major disturbances from orbit and counteract them (100%) • Single vs Multiple spacecraft (90%)

  6. Configuration & Structural Design Shelby Sullivan, Eric Weber • Find general hardware (cameras, thrusters, etc.) (100%) • Design structure (material, shape) (90%, pending necessary changes) • Solidwork components (60%)

  7. Attitude Determination & Control Shunsuke Hirayama, Tsutomu Hasegawa • Determine method of attitude control (80%) • Single vs Multiple cameras (90%)

  8. Power, Thermal & Communications Aziatun Burhan, Masao Shimada, Tomo Sugano • Determine power needed by satellite (70%) • Battery only vs Solar Cell + Battery (70%) • Define thermal environment (outside and inside sources) (80%) • Determine insulation needed (60%) • Determine transmission method (100%)

  9. Trade Studies • Expendable vs Recoverable Satellite • method of picture storage • viable method of recovery • reasonable amounts of extra fuel needed • Single vs Multiple Satellite(s) • amount of extra fuel needed for plane transfers • ability to “see” entire shuttle with only 1 satellite

  10. Solar cells + Battery vs Battery only • Amount of power solar cells can provide in 24 hr period • Amount of power needed by satellite components • Size of battery needed to compliment solar cells vs size of battery needed with no recharge • Single vs Multiple camera(s) • Ability to control attitude • Camera size

  11. Other Design Aspects • Structure: Rectangular satellite with aluminum supports, center of mass designed to be at the center of the prism. • Navigation: Will be using DGPS for location and velocity information, magnometer and gyro for attitude determination. • Transmission: Decided to store images on memory stick instead of using live transfer.

  12. Systems Integration and Management Rachel Winters Matt Whiten

  13. SIM • Role: Work with all groups to balance workload. • Tasks: • Research lightband technology • Perform trade study on attitude sensors • Research ARVD • Research, calculate and design recovery method. Matthew Whitten

  14. SIM • Attitude Sensors • Distance requires the camera to have the most accurate attitude control • Small satellite requires inexpensive and small equipment • Recovery Method • Robotic arm’s length must be able to reach the recovery orbit around the shuttle • Design and format end effect to capture satellite Matthew Whitten

  15. Special Requirements • Transmission restrictions • NASA operates in the S-band of frequencies, from 1700 - 2300 MHz, the space shuttle is generally contacted at 2106.4 and 2041.9 MHz, and the Orbiter also uses the Ku-band, from 15250 - 17250 MHz. • Vibration requirements • Vibration tests with NASA are usually done from 20 - 2000 Hz.

  16. Satellite-Shuttle Interactions • Capture feasibility case study • MIR Space capsule • SPARTON satellite • SFU Satellite • Automatic movement near to shuttle • Mini AERCam • STS-87

  17. Orbital Navigation and Control Group Members: Kyle Tholen Orbit Determination Delta V Estimation GPS Navigation Matt Mueller Effects of Earth’s Oblatness Propulsion Methods Orbit Modeling in STK

  18. Delta V estimation • Delta V for orbit transfers estimated with Clohessy Wiltshire equations:

  19. GPS Navigation • GPS can be used to determine position in orbit • Two signals are transmitted from GPS satellites • Precise Position Service (PPS) • Very accurate • Currently restricted to military applications • Standard Position Service (SPS) • Available for anyone to use • Not as accurate as PPS

  20. GPS Navigation Continued • Use Differential GPS (DGPS) for a much more accurate position • Need a known fixed reference position with GPS capabilities • Space Shuttle are GPS certified and position is known very accurately with ground tracking • DGPS can potentially be accurate to the centimeter.

  21. Orbit Determination • Need two orbits to view shuttle from all angles • Orbits achieved through small changes in Inclination and Eccentricity

  22. Causes secular drift in right ascension, argument of perigee and mean anomaly Effect Of Earth’s Oblatness

  23. Earth’s Oblatness Continued • Effect on shuttle and satellite nearly the same over 24 hr period deg deg deg • These values will give the change in the relative distance to the shuttle, estimation of deltaV needed to correct orbit.

  24. Propulsion Methods Requirements • Small amount of thrust • Capable of being used numerous times • Small size, light weight • Low price Possible candidates • Small mono-propellant hydrazine thrusters • Cold gas thrusters • Due to simplicity, ease of handling and price, cold gas thrusters were chosen as method of propulsion

  25. Orbit Modeling in STK • Visualization of relative orbit proved difficult without simulation • Created scale simulation of shuttle orbit as well as satellite orbit • Useful to visualize relative orbit about shuttle and aid in initial selection of orbit parameters • Use of MATLAB distance function determined final orbit parameters • Simulation proved orbit provided 100% visible coverage of shuttle

  26. STK Orbit Simulation

  27. Configuration & Structural Design Shelby Sullivan Eric Weber

  28. Satellite Structure Cube (60x60x50 cm) Aluminum Low cost and availability Success on many other satellites Adequate properties for mission Configuration Keep the moments of inertia near center of cube Allow space for large camera to see through one face Allow for proper thermal control Structure and Configuration

  29. Structure and Configuration

  30. Structure and Design Gyro Transceiver CPU Magnometer Thruster

  31. Structure and Design • Future Work • Reconfigure satellite structure to better accomplish design goals • Model remaining hardware • Place selected hardware to accomplish design goals

  32. Camera - MegaPlus II EP1600 16 Megapixel 4872 x 3248 Three sensor grades for “demanding applications” Selectable 8, 10, or 12 bits/pixel “Temperature Resistant” construction

  33. Lens - Nikon Super Telephoto 1000mm • Angle of view – 2 x 1.4 degrees • Length – 24 cm • Mass – 2 kg • Fixed focal length • Little to no moving parts • Higher vibration resistance • Higher temperature resistance

  34. Field of View

  35. Sample PicturesWith Pixels/Meter 2350 9500 600 ~ 360m from shuttle ~ 700m from shuttle 390 200

  36. ~360m From Shuttle • ~Cross-sectional are of shuttle • 400 m^2 • Field of View area • 105 m^2 • ~25% of shuttle captured per photo • Accuracy required for view of shuttle • X angle ~ 2.6° • Y angle ~ 0.86°

  37. 360 Meters from Shuttle

  38. Attitude Determination & Control Shunsuke Hirayama Tsutomu Hasegawa

  39. Why Zero momentum?

  40. Moment of inertia of a*b*h cube sat. h b a Once we get angular acceleration, we can get the Moment. Where, is body frame mex = Jώ + ω x (Jω) basedmoment From Nihon Univ. Text book Tsutomu and Shunsuke

  41. Attitude determination x y Front View Side View z

  42. Aerodynamic torque for worst case S = 0.4243 m2 Altitude 326-346km

  43. Gravity-Gradient Torque n3 = μ = 398600 km3/s2 R3 3263 km3

  44. Solar Radiation Pressure Torque Our surface material is Aluminum 0.02  K  0.04 (surface reflectivity) Is = 1358 w/m2 at 1 AU

  45. Choosing reaction wheel • Using Matlab we calculated required torque to change attitude with disturbances. The result is below: For Y axis Rise Time: 14.178531 Settling Time: 1.322471 Overshoot: 32.247096 % Max Torque: 0.024617 There is error so that we should work on matlab again. Max torque is 24.6mNm so that we use reaction wheel produced by Sunspace whose max torque is 50mNm.

  46. Problem about simulation • Disturbance torque is: Required torques is: We should figure out what is wrong and fix it.

  47. Requirement for reaction wheel The rotation speed of satellite should be: 360º/90min = 0.06667deg/s = 0.0698 rad/min - 1.163x10-3 rad/s It takes 90 min to go around the orbit. 360º/90min We use 0.1 rad/s as a rotation speed in matlab

  48. Future work • calculate a disturbance from magnetic torque. • work on matlab with all disturbances.

  49. Communications Tomo Sugano

More Related