AERO 4730 Space Mission Design               
 

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AERO 4740

Space Mission Design Lecture 7

What's happening in space:

Elektron (Russian Oxygen Generator): Liquid Tank #7 experienced three shutdowns on Tuesday, Sept. 7 (not related to previous shutdowns that were attributed to gas bubbles in the gas lines) and troubleshooting was unsuccessful. The unit is turned off. The Russian specialists believe the current shutdown could be due to one of the following: the Elektron gas analyzers that detect O2 and H2 in the Elektron lines are faulty or the Elektron is producing "contaminated" gases, with the possible introduction of H2 into the O2 lines.

Further troubleshooting on tank #7 has been deferred until Wednesday, Sept. 8 to coincide with the scheduled tank #5 repair and recovery. For the #5 repair, the crew will be installing new external pumps on #5 in an attempt to recover its functionality. These pumps were launched on 8S and have been designed to be less susceptible to air bubbles.

On Orbit Debrief: Flight Engineer Mike Fincke participated in his first on-orbit debrief for the flight crew equipment subsystem. The intent is to complete as much productive debrief time on-orbit with the information fresh in the crew's mind and the hardware readily available. The crew has chosen to participate in on orbit debriefs during their personal time to help reduce the amount of time post-flight dedicated to debriefs.

Life Support Requirements

Objectives

  • Understand the environmental parameters important to humans in space
  • Know the basic needs of humans for staying alive and healthy in space
  • Be able to construct a functional flow diagram for life support systems

    Life Support Requirements

  • Human needs:
  • Air (O2, CO2, pressure, temperature, humidity, cleanliness)
  • Water, Food
  • Protection (radiation, noise, vibration, acceleration)
  • Metabolic balance

    Environmental Parameters

  • To keep humans alive
  • Air, Food, Water
  • Protection from:
  • Temperature
  • Vacuum
  • Radiation exposure
  • MMOD

    Considerations for human comfort

  • Clothing
  • Waste management
  • Noise
  • Vibration
  • Lighting
  • Acceleration

    Atmosphere Pressure:

    Ptot = pO2 + pN2 + pCO2 + pH2O +…traces

    Standard values:

    101.3 = 21.3 + 78 + 0.03 + 0.4 + …traces
    Kilopascals (or roughly %)

    Oxygen

  • Human usage:
  • ~ 600 liters/person/day (~ 0.85 kg/person/day)
  • ~ 0.02 kg/day leakage (ISS has been less)

    Nitrogen

  • Not consumed
  • Periodically replenish for leakage or EVA losses
  • Can substitute other gases

    Carbon dioxide

  • CO2 levels:
  • Auburn ~ 0.03% (0.03 kPa)
  • Space Shuttle ~ 0.2 – 0.3 %
  • ISS ~ 0.6 – 1.0 %
  • Safety limit: 1%
  • Must remove ~ 20 liters/person/day
  • Eliminate with:
  • Absorbers - LiOH canisters
  • Regenerators - Vozduch, CDRA

    Pressure vs. % O2

    Other Atmospherics

  • Ventilation
  • CO2 pockets
  • 0.05-0.2 m/s
  • Exercise - .42 m/s
  • Contaminants
  • Dust, skin, hair, lint, food, offgassed products
  • Filtering required
  • < 0.05 mg/m3 desired

    Water - most massive consumable for human spaceflight

  • Planning (kg/person/day)
  • Potable water - 2.8
  • Personal hygiene – 1.1 (7.0 if shower)
  • Flush – 0.5
  • Clothes wash – 12.5 (if desired)
  • Dish wash – 5.4 (if desired)
  • Can normally recover water
  • Except flush water and urine (harder)
  • 2 kg/person/day consumed on ISS
  • 100 lb bags of water

    Food

  • 2300-3200 kcal/person/day (~1.6 kg/p/d)
  • Nutritional balance and variety are important
  • Food storage

    Clothing

  • Launch and entry suits (LES)
  • U.S. LES
  • Russian Sokol
  • Extra Vehicular Activity (EVA) suits (space suits)
  • U.S. EMU (EVA mobility Unit)
  • Russian Orlan
  • On orbit clothing
  • Daily wear
  • Penguin
  • Survival
  • Launch and Entry Suits
  • Party clothes

    Waste Management

  • Humans generate waste
  • Urine
  • Feces
  • Trash
  • CO2
  • Humidity
  • Must store, remove or re-use it
  • Tanks, cans, bags
  • Overboard dump
  • Burn up in atmosphere
  • Return to Earth
  • Regeneration

    Protection from hazards

  • Pressure vessel
  • MMOD protection
  • Radiation shielding
  • Temperature controlled
  • Cabin: 18-28 ºC
  • Touch: 4-45 ºC (momentary to 49 ºC)

    Other comfort considerations

  • Noise
  • Vibration
  • Lighting
  • Acceleration

    Challenges to Life and Health in Space

  • Vacuum
  • ~ ½ of Earth’s atmosphere is below 5 km MSL
  • Above ~14.4 km, can no longer breathe with the available air
  • pressure in the lungs = pressure of the atmosphere
  • Above ~60 km, curvature of Earth becomes noticeable and the sky is black
  • not enough atmosphere to scatter light
  • Weightlessness (freefall)
  • Radiation (electromagnetic and particulate)
  • Micrometeroids (become micrometeorites after they fall to Earth)
  • Thermal Extremes
  • Spacecraft environment in LEO ranges from approximately -120 to +110°C

    Life Support Basics

  • AIR / WATER / FOOD
  • 3 min / 3 days / 3 weeks
  • Atmosphere Pressure and Composition
  • Thermal Control
  • Humidity Control
  • Radiation and Debris Shielding
  • Artificial Gravity????

    Consumables / Waste Products / Environment

  • I/O parameters – oxygen (ppO2), water, food / CO2, urine, feces, respiration, perspiration and heat

    Desirable Life Support system Attributes

  • 1. Mission appropriate
  • 2. Highly reliable
  • 3. Largely autonomous
  • 4. Integrated functionality

    Environmental parameters –

  • atmospheric pressure, temperature and humidity, radiation, light, sound, etc.

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