ASEN 5158 Space Habitat Design

10/14/2008

Chapter 12 Transfer, Entry, Landing and Ascent Vehicles

 

Learning Objectives

  1. Integrate prior info into design parameters
    1. Apply design process from Ch. 1 and 2
    2. Incorporate environment factors from Ch. 3 and 4
    3. Consider human-related design drivers from Ch. 5, 6 and 7
    4. Include safety considerations from Ch. 8
    5. Determine propellant mass requirements from Ch. 9 and 10
    6. Evaluate elements from Ch. 11
  2. Define subsystems
  3. Calculate initial mass budget estimatee

Mission Phase Design Drivers

•         Test and Pad Ops

•         Earth ascent

•         Space transfer

•         Descent/landing/ascent (moon, Mars)

•         Surface habitat

•         Space transfer

•         Earth reentry and Landing

Staging

•         Launch and habitat elements

•         Expendable vs. reusable stages (e.g., STS ET)

•         Separate elements

–        Simplify development (one element = one function), aid in launch packaging, allow incremental system upgrades

•         Single element

–        Potential to reduce mass and volume, reduce number of parts (i.e., failure modes) and interfaces

Piloted Reentry Vehicles

•         Aerobraking / aerodynamics / propulsion

•         Landing accuracy

•         Volume efficiency

•         Landing modes / vehicle shapes

Landing Modes

•         Propulsive

–        Vertical descent, some control, struts, shocks

•         Lifting or Ballistic parachute

–        Vertical descent, no control, shocks, airbags retros

•         Parafoil

–        Aerodynamic flare, moderate glide, retros

•         Deployable wing

–        Moderate to high directional control, wheels, shocks

•         Lifting body and Winged

–        High directional control, wheels, shocks

Human Subsystem

•         Starting point in the design process

•         Address life support and habitability factors (Ch. 5 and 6) and psychological concerns, to some extend (Ch. 7)

•         Define safety philosophy and implementation plan (Ch. 8)

Vehicle Subsystems

•         Structure

•         ECLSS

•         Crew / Payload Accommodations

•         Avionics

•         Electrical Power

•         Thermal Control

•         Propulsion and RCS

Developing Conceptual Designs

  1. Estimate pressurized volume needed
  2. Estimate initial vehicle mass
  3. Estimate propellant mass (Ideal Rocket Eqn.)
  4. Refine vehicle mass
  5. Create initial sketch with subsystems
  6. Define mass properties (for subsystems)
  7. Estimate power and thermal requirements
  8. Integrate design
  9. Estimate cost
  10. (Evaluate options and select baseline)

 

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