1. Detailed Design Review Team Members:Josh Benton Nathan Bialke Sean Bradburn Liana Garbowski Robert Lane Garrett Manfull Presented To:Marc Murbach March 1, 2007

2. 2 Project Value

3. 3 SOAREX ► Aligned with SOAREX goals  Sub-orbital atmospheric experimentation  Innovative method of data gathering  Improved understanding of atmospheric data collection without conventional sensors

4. 4 Future Use Potential ► Atmospheric data collection – other planets  Small  Relatively inexpensive  Expendable ► Mars lander missions  Improved landing accuracy through real-time atmospheric data collection

5. 5 System Overview

6. 6 ► Atmospheric data collection device  Activation: redundant mechanical switching upon ejection  Data transmission: radar transponder and radar antenna; data tracked by ground base  Thermal protection: spherical Teflon probe body enclosing all components  Data extraction: atmospheric properties backed out through software math model

7. 7 Mechanical Review

8. 8 Mechanical Overview

9. 9 Probe Body – Bottom Shell

10. 10 Probe Body – Bottom Shell

11. 11 Probe Body – Bottom Shell ► Strengths  Concentration of mass ensures probe will fall in a “bottom-first” orientation  Single-material construction ► Solves coefficient of expansion problems ► No delamination  Teflon advantages ► Highly machinable ► Favorable heating properties

12. 12 Probe Body – Bottom Shell ► Improvements needed  Mass reduction (bottom is ~8 lbs. by itself)  Potential heat-related design revisions ► Awaiting completion of heat modeling

13. 13 Probe Body – Bottom Shell ► Potential failure modes  Excess ablation rendering data useless or complete meltdown ► Actions taken: analytical heat modeling, possibly arc-jet testing  Separation from upper shell ► Actions taken: Metal Key-sert threaded inserts used to strengthen attachment points

14. 14 Probe Body – Top Shell

15. 15 Probe Body – Top Shell

16. 16 Probe Body – Top Shell ► Strengths  “Shelled out” design ensures mass will be significantly less than bottom half of sphere  Constructed from Teflon ► Same expansion coefficient as bottom shell ► Same favorable heating properties as bottom shell

17. 17 Probe Body – Top Shell ► Improvements needed  Mass reduction (possibly change to a less-dense material with a similar coefficient of expansion)

18. 18 Probe Body – Top Shell ► Potential failure modes  Heat-related failure, allowing deformation or separation from bottom shell ► Actions taken: “worst-case” heat modeling

19. 19 Switch Assembly

20. 20 Switch Assembly

21. 21 Switch Assembly ► Strengths  Activation requires 2 of 3 switches to activate ► Protection from premature single-switch activation ► Protection from single-switch failure  Switch operation not reliant on probe orientation in foam  Moving parts ejected from probe upon activation

22. 22 Switch Assembly ► Improvements needed:  (Possibly) longer activation plungers and springs to meet 2” extension-before-activation criteria  Possible relocation of activation points at different locations on probe body

23. 23 Switch Assembly ► Potential failure modes  Heat-related failure prior to activation ► Actions taken: plunger holes slightly oversized for thermal expansion/contraction  Early activation ► Actions taken: redundant switch setup, simple 1- moving-part design, switches locked in fully- depressed position before activation, backing plate to be placed in foam above switch area to prevent foam erosion

24. 24 Electrical Review

25. 25 Electrical Overview ► System schematic

26. 26 Batteries

27. 27 Batteries ► Strengths  Two independent 14.4V lithium ion battery packs, each capable of powering probe  Battery controller isolates battery packs

28. 28 Batteries ► Improvements needed  Potential mass reduction, if necessary  Size reduction or arrangement reconfiguration

29. 29 Batteries ► Potential failure modes  Battery failure, loss of voltage ► Actions taken: Use of two redundant battery packs; either one can completely power probe  Reversed battery polarity ► Actions taken: Battery controller will isolate backwards battery from properly installed battery, which will power probe  Failure of electrical connections ► Actions taken: : Connections made with terminal blocks using mechanical compression rather than solder

30. 30 Batteries ► Potential failure modes, continued  Thermal-related failure resulting in explosion or fire from overcharge or over-discharge ► Actions taken: Battery controller prevents overvoltage, undervoltage, and completely isolates two battery packs

31. 31 Radar Transponder/Antenna

32. 32 Radar Transponder/Antenna ► Supplied components  Problem: The components are not verifiable – UI doesn’t have any mechanisms for testing a radar transponder or antenna  Solution: Currently an open issue – will require attention at NASA Ames for verification

33. 33 Modeling

34. 34 Heat Model ► Fay-Riddell:  ρ, V from Robert’s trajectory model ► To find stagnation point temperature:  Can then determine ablation – significant after ~400 degrees C

35. 35 Heat Model ► Linear Ablation:  S – linear ablation  ρ ∞ - free stream density  R – nose radius  V ∞ - free stream velocity

36. 36 Trajectory Model

37. 37 Trajectory Model

38. 38 Trajectory Model

39. 39 Trajectory Model

40. 40 Ablation

41. 41 System Functionality Status

42. 42 Mechanical Functionality ► Probe body – bottom shell  Integration with components functional; awaiting heat modeling to verify design ► Probe body – top shell  Status same as bottom shell ► Switch assembly  Fully functional and undergoing failure testing

43. 43 Electrical Functionality ► Batteries  Functional and in our possession ► Radar Transponder  Awaiting delivery ► Radar Antenna  Awaiting delivery

44. 44 Open Issues

45. 45 Open Issues ► Weight – too great?  Increased ballistic coefficient; increased heating  Do we need to change to a different material? ► Modeling not yet complete ► Final design dependent on results of modeling  Must withstand heating  Must be able to generate useful data

46. 46 Budget Report

47. 47 Budget

48. 48 Battery Controller Schematic

49. 49 Voltage Regulation Schematic