1 / 63

There is always Space for Quality

There is always Space for Quality. Dr Mark English. Space and Software. Cassini / Huygens – the plan. 3.5 Billion kms. Cassini/Huygens. Mariner MKII spacecraft. Source: NASA. Cassini. Mariner MKII spacecraft. Source: NASA. Cassini/Huygens Flight Model. Mariner MKII spacecraft.

teagan-gaines
Download Presentation

There is always Space for Quality

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. There is always Space for Quality Dr Mark English

  2. Space and Software

  3. Cassini / Huygens – the plan 3.5 Billion kms

  4. Cassini/Huygens Mariner MKII spacecraft Source: NASA

  5. Cassini Mariner MKII spacecraft Source: NASA

  6. Cassini/Huygens Flight Model Mariner MKII spacecraft

  7. The Surface Science Package Source: John Zarnecki, PSSRI, Open University, UK

  8. Cassini / Huygens – the plan 3.5 Billion kms

  9. Titan Titan’s vital statistics: Diameter – 5150km; Orbital/rotational period – 15.95 days Only planetary satellite with atmosphere Column mass ~ 10 x value for Earth Atmospheric Composition Nitrogen and rich array of hydrocarbons and nitriles Hidden Surface Obscured by photochemical haze Indirect evidence for surface seas/lakes Model for early Earth?

  10. Overall model of Titan Source: R. Lorenz

  11. Considerations Delivery mechanisms Target environment Transition environment Duration of operation Nature of operation Sound familiar?

  12. Design and Build Look at key facts – with tolerance Temperature Vacuum Radiation Time Chemistry Zero gravity

  13. The Mission

  14. Survival Launch – shaking (a lot) Cruise – radiation & vacuum Cruise – thermal control Cruise – temperature cycling Trajectory and SOI – accuracy Entry & Surface mission - cold

  15. Launch

  16. Getting through Launch Make it ... then shake it

  17. Cruise

  18. The flight plan VVEJGA Source: NASA

  19. The flight plan Source: BBC

  20. Temperature Control Gets cold out there No solar panels for electric heating Too far, sun too weak Too much dust Use RTGs for power Use RHUs for on-platform heat

  21. Keeping warm

  22. Keeping warm

  23. Radiation Sources Natural (Sun, Cosmic) RTGs RHUs Total dose to outside of shield 24.15 kRads Qual level ... double it

  24. Proven technology No Moving parts No lubricant Solid actuators No normal solder Crystallisation Outgassed plastics No nasty condensation

  25. Proven technology Radhard ICs Care with Digital and analogue lines Waiver and qualification for E2PROMS

  26. You can never go back Dorothy Once it is launched there is no maintenance ... It has to work first time, the first time... How do you get to this level of quality?

  27. Systems engineering Developed through Minuteman, Used on Apollo Working to interfaces, and specifications Big design, modular breakdown

  28. Modules See this in Software ... Code libraries (NAG) Component based development Requires very strict library management and definition

  29. Libraries Numerical Algorithms Group http://www.nag.co.uk/

  30. Libraries Not enough to know what things do How were they tested? What tolerances were on that data? What operational environment? What Units?

  31. Failures Mars has swallowed 12 missions Mars observer 1993 Mars global surveyor 1996 Mars climate orbiter 1999 Ariane 5 1996

  32. Caveat Any well meaning highly skilled operator can try and do something and screw it up like any of us You get this in all industries.

  33. Cassini / Huygens – the plan 3.5 Billion kms

  34. SOI

  35. Arriving at Saturn Saturn Orbit Insertion Turned spacecraft round Fired motors for 96 Minutes Source: Huygens Mission Operations Plan

  36. Arriving at Saturn Source: Huygens Mission Operations Plan

  37. Ejection

  38. How Cassini supports Huygens Radio uplink during mission using HGA Source: NASA

  39. Atmospheric Entry and Surface Mission

  40. Any other risks? Hm......

  41. Atmospheric Models Yelle et al. 1997

  42. Huygens descent timelines Source: John Zarnecki, PSSRI, Open University, UK / ESA

  43. Parachute Test A test drop was done on Earth Source: ESA

  44. SSP Measure: Temperature Speed of sound Acceleration Refractive properties Liquid Density Thermal Properties Electrical Properties Angle of tilt Source: PSSRI

  45. SSP Measure: Temperature Speed of sound Acceleration Refractive properties Liquid Density Thermal Properties Electrical Properties Angle of tilt Source: PSSRI

  46. Shake and Bake (!) Source: John Zarnecki, PSSRI, Open University, UK

  47. Prepare the spacecraft

  48. Cassini Mariner MKII spacecraft Source: NASA

  49. Design Constraints Survive Launch Very high G shock Radiation proof (Rad hard) Solar radiation RHUs and RTGs Reliable over 7 years cruise Vacuum Zero gravity Reliable during 69 orbits Surface mission Atmospheric entry Cryogenic cooling (-200 degC) Dunking into Liquid Ethane/Methane mix Manufactured in 1994

More Related