1. February 1, 2005HYPERION ERAU 1 Thermal Analysis of a Radiation Shield for Antimatter Rocketry Concepts Jon Webb Embry Riddle Aeronautical University

2. February 1, 2005HYPERION ERAU 2 Agenda Why Hyperion Rocket Principles Why antimatter Velocity Profile and Fundamentals Thermal Considerations

3. February 1, 2005HYPERION ERAU 3 Why fly so fast in space? Space flight takes to long!

4. February 1, 2005HYPERION ERAU 4 Microgravity Environment Skeletal and Muscular atrophy can make it impossible to return to the surface of Earth!

5. February 1, 2005HYPERION ERAU 5 Cosmic Radiation Radiation in space is lethal!!

6. February 1, 2005HYPERION ERAU 6 Rocket Principles Specific Impulse is the fuel efficiency of a rocket engine As fuel energy density increases so does Specific Impulse and delta V The equation for Specific Impulse is:

7. February 1, 2005HYPERION ERAU 7 Rocket Principles Thrust is a force Thrust is the time rate change of propellant momentum Momentum is the mass of fuel ejected multiplied by the exhaust velocity

8. February 1, 2005HYPERION ERAU 8 Chemical Rocketry LO/LH2

9. February 1, 2005HYPERION ERAU 9 Fuel Energy Density

10. February 1, 2005HYPERION ERAU 10 What is antimatter (positrons) Produces photons isotropically Produces photons back to back 0.511 MeV per photon

11. February 1, 2005HYPERION ERAU 11 How do we propel a S/C

12. February 1, 2005HYPERION ERAU 12 Shield Design (Rad. Lengths)

13. February 1, 2005HYPERION ERAU 13 Shield Design Made of Tungsten Melting point of 3600 K Density of 19.3 gm/cm 3 Radiation length is 0.35 cm 5 radiation lengths thick Roughly 1.75 cm thick

14. February 1, 2005HYPERION ERAU 14 Shield Design (Dimension)

15. February 1, 2005HYPERION ERAU 15 Shield Design (Mass)

16. February 1, 2005HYPERION ERAU 16 Momentum Attenuation Compton Scattering Brehmstralling Photo-electric Effect - photons/electrons ejected at random angles - Might reduce momentum/cosine average Monte-Carlo analysis is being developed to research effects electron Atom

17. February 1, 2005HYPERION ERAU 17 Thermal Problem Energy is lost as heat in the tungsten shield We must find a way to dissipate the heat in order to augment the thrust We must find a way to regain the energy lost from the heat to augment efficiency (Isp)

18. February 1, 2005HYPERION ERAU 18 Shield Thermal Loading

19. February 1, 2005HYPERION ERAU 19 Radiative Cooling For highest Isp we must find the steady state condition where blackbody radiation equals input energy. This will severely limit the thrust E radiated E thermal, P thrust

20. February 1, 2005HYPERION ERAU 20 Radiative Cooling View Factors must be examined The extreme limits of the pi/2 to –pi/2 shield may re- radiate energy into the other side of the shield.

21. February 1, 2005HYPERION ERAU 21 Radiative Cooling We may want to consider making the shield flat and very large, or decrease the angular limits of the shield. Annihilate e + inside shield

22. February 1, 2005HYPERION ERAU 22 Radiative Cooling D AP R R All Values in Radians

23. February 1, 2005HYPERION ERAU 23 Radiative Cooling

24. February 1, 2005HYPERION ERAU 24 Radiative Cooling

25. February 1, 2005HYPERION ERAU 25 Radiative Cooling

26. February 1, 2005HYPERION ERAU 26 Radiative Cooling 1. 7. 2. 3. 8. 4. 5. 6.

27. February 1, 2005HYPERION ERAU 27 Radiative Cooling

28. February 1, 2005HYPERION ERAU 28 Radiative Thrust

29. February 1, 2005HYPERION ERAU 29 Convective Cooling Use liquid Hydrogen or Ammonia to absorb excess heat Allow fluid to expand across the shield to produce thrust with a decreased I sp

30. February 1, 2005HYPERION ERAU 30 Convective Cooling LH2 Properties -C p = 10,000 J/ (kg.K) -h = 210 W/(m 2.K) -T LH2 = 16 K -T shld = 3300 K

31. February 1, 2005HYPERION ERAU 31 Convective Power Transfer 1. 2.

32. February 1, 2005HYPERION ERAU 32 LH 2 Mass Flow Rate 3. 4. 5.

33. February 1, 2005HYPERION ERAU 33 LH2 Mass Flow Rate

34. February 1, 2005HYPERION ERAU 34 Convective Thrust from LH 2 6. 7. 9. 10.

35. February 1, 2005HYPERION ERAU 35 Convective Thrust from LH 2

36. February 1, 2005HYPERION ERAU 36 Shield Thrust to Weight Ratio

37. February 1, 2005HYPERION ERAU 37 Convective Specific Impulse 11. 12. 13. 14.

38. February 1, 2005HYPERION ERAU 38 Specific Impulse vs. Shield Temp.

39. February 1, 2005HYPERION ERAU 39 Thrust Augmentation Shield Mass: 170 Mt 10 Shields Shield Area: 10,000m 2 Thrust: 1.70 MN I sp : 826 seconds 5 rad. lengths 10 sub-shields

40. February 1, 2005HYPERION ERAU 40 Convective Case Study 1 M S/C = 40 Mt F = 1.70 MN A = 10,000 m 2 P = 6,896 MW M sh = 170 Mt M d = 210 Mt Mdot e+ = 7.662 x 10 -8 kg/s Mdot H2 = 210 kg/s

41. February 1, 2005HYPERION ERAU 41 Convective Case Study 1

42. February 1, 2005HYPERION ERAU 42 Convective Case Study 1

43. February 1, 2005HYPERION ERAU 43 Convective Case Study 2 M S/C = 40 Mt F= 261.9 kN A= 1130.4 m 2 P= 780 MW M sh = 19.2 Mt M d = 66.113 Mt Mdot e+ = 4.33 x 10 -9 kg/s Mdot H2 = 23.7 kg/s

44. February 1, 2005HYPERION ERAU 44 Convective Case Study 2

45. February 1, 2005HYPERION ERAU 45 Convective Case Study 2

46. February 1, 2005HYPERION ERAU 46 Convective Case Study

47. February 1, 2005HYPERION ERAU 47 Further Convective Work Combine case studies into 3-D graphs (dV vs. IMLEO/H2/e+ mass vs. shield mass/radius/area) Research energy/heat deposition as a function of thickness plus H2 gaps Increase SA without increasing mass

48. February 1, 2005HYPERION ERAU 48 Electrical Power Production Another option is to use a working fluid that can be expanded through a turbine to produce electricity This would allow for low thrust missions and provide the spacecraft with electricity for its subcomponents

49. February 1, 2005HYPERION ERAU 49 Tri-Modal Operation Lastly the engine could be cooled with LH2 when large thrust is needed and operate in a radiative mode to slowly accelerate S/C in interplanetary space. When the engine is in a radiative mode, electricity can be produced

50. February 1, 2005HYPERION ERAU 50 Concluding Remarks Antimatter offers extraordinary propulsion capabilities Unfortunately thermal challenges are quite daunting Production and storage are a whole different challenge

51. February 1, 2005HYPERION ERAU 51 Concluding Remarks Advantages warrant serious look Possible high I sp uses as a thermal rocket by increasing the shield surface area Best method is to use the reflecting shield

52. February 1, 2005HYPERION ERAU 52 Questions or Comments ????

53. February 1, 2005HYPERION ERAU 53 Backup Slides

54. February 1, 2005HYPERION ERAU 54 Propulsion Systems Goal is to obtain highest Isp

55. February 1, 2005HYPERION ERAU 55 Antiprotons Statistically complicated Produces massive particles

56. February 1, 2005HYPERION ERAU 56 Flight Times

57. February 1, 2005HYPERION ERAU 57 Flight Times

58. February 1, 2005HYPERION ERAU 58 Flight Times

59. February 1, 2005HYPERION ERAU 59 Flight Times

60. February 1, 2005HYPERION ERAU 60 Lunar Flight Times

61. February 1, 2005HYPERION ERAU 61 Lunar Flight Times

62. February 1, 2005HYPERION ERAU 62 Interstellar Flight Times