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SPAAAAAAAAACE

listrophy
August 12, 2014

 SPAAAAAAAAACE

Let's learn us a space exploration! In this talk, Brad will wax poetic on the particulars of getting into space, getting around in space, and getting things done in space. PID controllers, orbital insertion, and how rockets work by smashing molecules together. There may or may not be any math, programming, or vacuum-induced hypoxia in this talk.

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August 12, 2014
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  1. Carl Sagan
    Pale Blue Dot
    Photo in public domain via Wikimedia Commons

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  2. Photos in public domain via Wikimedia Commons

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  3. Photos in public domain via Wikimedia Commons
    Charlie Duke photo courtesy of charlieduke.net

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  4. Apollo Guidance Computer
    Compared to iPhone 5S:
    • 284 times heavier
    • 2600 times slower (Hz)
    • 17 million times less memory
    Photo in public domain via Wikimedia Commons

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  5. image credit: imgur.com/Cuwy6wZ

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  6. image courtesy: kickstarter.com
    image courtesy: louxfamilyblog.com

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  7. image courtesy: mic.com
    image courtesy: atlantablackstar.com

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  8. Boeing
    Lockheed Martin
    United Space Alliance
    SpaceX
    Bigelow Aerospace
    Armadillo Aerospace
    Hamilton Sundstrand

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  9. Brad Grzesiak
    CEO, Bendyworks
    @listrophy

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  10. A Fire Upon the Deep
    Ashes of Victory
    At All Costs
    Earth Unaware
    Echoes of Honor
    Ender’s Game
    Children of the Mind
    Ender’s Shadow
    First Meetings
    Flag in Exile
    Honor Among Enemies
    Field of Dishonor
    An Incomplete List
    In Enemy Hands
    Mission of Honor
    On Basilisk Station
    Shadow Puppets
    Shadow of the Giant
    Shadow of the Hegemon
    Red Mars
    Speaker for the Dead
    The Short Victorious War
    War of Honor
    Wool
    The Honor of the Queen

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  11. Pre-Bendyworks
    Photos courtesy NASA & Michael Fidler

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  12. Launch
    Orbit
    Landing

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  13. “Rocket Science”

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  14. Orbital Requirements
    • 1 Large Body, 1 Small Body
    • Circumferential Velocity
    • Only Gravity
    • No Intersection

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  15. Let’s Do a Physics!

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  16. Photo in public domain via Wikimedia Commons

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  17. Portland
    Seattle
    2.1º

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  18. Portland → Seattle
    • 145 miles
    • 30 seconds
    • >17,000 mph

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  19. Kinetic Energy
    Ek = ½ m v2
    Ek / kg = ½ (17,000 mph)2
    Ek / kg = 29.6 MJ

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  20. Potential Energy
    Ep = mgh
    Ep / kg = (9.81 m/s2)(330 km)
    Ep / kg = 3.2 MJ

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  21. Kinetic (speed)
    vs.
    Potential (height)
    Speed = 29.6 MJ
    Height = 3.2 MJ

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  22. Equatorial Surface Speed
    • 1,040 mph
    • With help: 16,000 mph
    • Without help: 17,000 mph
    • Savings: ~5.4%

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  23. Conservation of
    Momentum

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  24. Momentum
    # p = mv!
    !
    def momentum(grams, meters_per_second)!
    grams * meters_per_second!
    end

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  25. Conservation of Momentum
    def system_momentum(objects)!
    objects.reduce(0) do |sum, (mass, velocity)|!
    sum + momentum(mass, velocity)!
    end!
    end!
    !
    !
    assert_equal \!
    system_momentum([[100 , 0 ], [100_000 , 0 ]]),!
    system_momentum([[100 , -10 ], [100_000 , 0.01 ]])!
    # g m/s g m/s

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  26. Conservation of Momentum
    def system_momentum(objects)!
    objects.reduce(0) do |sum, (mass, velocity)|!
    sum + momentum(mass, velocity)!
    end!
    end!
    !
    K = 1_000!
    assert_equal \!
    system_momentum([[100*K, 0*K], [100_000*K, 0*K ]]),!
    system_momentum([[100*K, -10*K], [100_000*K, 0.01*K]])!
    # kg km/s kg km/s
    (modified for rocketry)

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  27. One Weird Trick!

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  28. Converging-Diverging
    Nozzle
    choke
    SPEED!
    LIMIT
    1
    MACH
    Mach!
    13
    High
    Pressure

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  29. Kepler’s Laws of
    Planetary Motion

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  30. Kepler’s First Law
    Diagrams will not be to scale

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  31. Eccentricity
    def type_of_trajectory(e)!
    case e!
    when 0.0 then :circle!
    when 0.0...1.0 then :ellipse!
    when 1.0 then :parabola!
    else :hyperbola!
    end!
    end

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  32. Eccentricities
    Eccentricities = {!
    earth: 0.0167,!
    venus: 0.0067,!
    neptune: 0.00868,!
    # ...!
    }

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  33. Orbital Points of Interest
    peri- apo-
    Closest Farthest
    Earth Perigee Apogee
    Sun Perihelion Aphelion
    Any Periapsis Apoapsis

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  34. Kepler’s Second Law
    Fastest
    Slowest

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  35. Kepler’s Third Law
    # P₁² P₂²!
    # --- = ---!
    # a₁³ a₂³!
    !
    def solar_period(distance_in_au)!
    Math.sqrt(!
    365.26**2 / # earth's period!
    1**3 * # earth's distance in AU!
    distance_in_au**3!
    )!
    end

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  36. Orbital Periods
    Distance (AU) Duration (days)
    Earth 1.0 365.26
    Venus 0.73 (-27%) 226.5 (-38%)
    Mars 1.52 (+52%) 686.7 (+88%)

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  37. Kepler’s Laws of
    Planetary Motion
    1. Orbits are elliptical
    2. Faster when closer; Slower when farther
    3. Big orbits take longer

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  38. Trip to Mars

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  39. 29.8 km/s
    32.7 km/s
    Leaving Earth

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  40. Arriving at Mars
    21.5 km/s
    24.1 km/s
    Trip Length: 8.5 months

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  41. Hohmann Transfer
    Orbit

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  42. Landing
    • Moon
    • Mars
    • Earth (return trip)

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  43. Earth Mars

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  44. Aerobraking
    • Distance so far: 364 million miles
    • Aerobraking window: <100 miles?

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  45. Retrorockets

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  46. Kerbal Space
    Program

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  47. require 'excon'!
    require 'kuby'!
    !
    link = Kuby::Link.new!
    link.connect! or fail 'Could not connect'!
    !
    link.throttle_full!
    link.toggle_sas!
    !
    link.stage! and sleep 2!
    !
    prev_err = error =!
    integral = derivative = 0.0!
    !
    prev_time = link.mission_time
    gitlab.com/listrophy/spaaaaaaaaace

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  48. loop do!
    cur_time = link.mission_time!
    dt = cur_time - prev_time!
    error = 150.0 - link.altitude!
    integral = integral + error * dt!
    derivative = (error - prev_err)/dt!
    !
    kp, ki, kd = 0.1, 0.003, 0.08!
    new_throttle = (kp*error + ki*integral + kd*derivative)!
    !
    new_throttle = 1.0 if new_throttle > 1.0!
    new_throttle = 0.0 if new_throttle < 0.0!
    !
    link.set_throttle new_throttle!
    !
    prev_err, prev_time = error, cur_time!
    sleep 0.2!
    end
    gitlab.com/listrophy/spaaaaaaaaace

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  49. Throttle → Height
    • Force = mass * acceleration
    • ∫ acceleration dt = velocity
    • ∫ velocity dt = height

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  50. loop do!
    cur_time = link.mission_time!
    dt = cur_time - prev_time!
    error = 150.0 - link.altitude!
    integral = integral + error * dt!
    derivative = (error - prev_err)/dt!
    !
    kp, ki, kd = 0.1, 0.003, 0.08!
    new_throttle = (kp*error + ki*integral + kd*derivative)!
    !
    new_throttle = 1.0 if new_throttle > 1.0!
    new_throttle = 0.0 if new_throttle < 0.0!
    !
    link.set_throttle new_throttle!
    !
    prev_err, prev_time = error, cur_time!
    sleep 0.2!
    end
    gitlab.com/listrophy/spaaaaaaaaace

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  51. Launch, Orbit,
    Landing
    Nuclear Pulse Propulsion

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  52. Photo in public domain via Wikimedia Commons

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  53. Thank You
    @listrophy
    @bendyworks

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