LLAMBDA Review: Lunar Landing Architecture with a MarsBack Design Approach

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LLAMBDA ReviewLunar Landing Architecture with a
Mars-Back Design Approach

• TARR
• February 23, 2005

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Motivation

• January 14, 2004 President Bush announced a new
  vision for space exploration.
• Goal Send humans to the moon and Mars.
• Constraint Pay as you go
• Our Approach re-use designs
• Use modularity within mission architecture
• Exploit commonalities between moon and Mars
  missions (Mars-back approach)

Systems Finale Doshi
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Problem Statement

• Design a lunar landing capability
• that will transport a crew to and from the
  surface of the moon, whose
• key elements can ultimately be incorporated into
  a Mars landing mission.

Systems Finale Doshi
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Live or Die Goals

• Transport 3 people to and from the lunar surface
  and support them for 4 days
• Transport 4 people to and from the lunar surface
  and support them for 1 day, and remain dormant
  during long duration surface stays of up to 180
  days (while crew is in a separate habitat)
• Transport 1 metric ton of payload to the moon in
  addition to crew
• Be capable of landing the crew at any latitude
  and longitude location on the moon
• Abort the mission at any time and return the crew
  safely to the Earth

Systems Finale Doshi
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Overview of Architectures

• Architecture 1 Lunar Orbit Rendezvous
• Crew travels to low lunar orbit in CEV
• Separate Lander for crew descent/ascent
• Rendezvous for return
• Architecture 2 Lunar Direct
• CEV carries crew directly to lunar surface and
  back to earth
• Architecture 3 Hybrid Lunar Orbit Rendezvous
• CEV carries crew directly to lunar surface
• Propellant for return left in orbit
• CEV rendezvous with Prop. for return

Systems Team Finale Doshi
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Architecture 1 LOR
Lunar surface
Systems Team Finale Doshi
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Architecture 2 LD
Lunar surface
Systems Team Finale Doshi
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Architecture 3 HLOR
Lunar surface
Systems Team Finale Doshi
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Work completed

• Class split into 3 teams, each investigating the
  lunar landing capability of one architecture
• Each architecture considered
• Sequence of operations
• System interfaces
• Design drivers
• Systems-level trades
• Mass and Delta-V estimates
• Major sources of risk
• Applications to a Mars-back approach

Systems Team Laura Condon
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Architecture 1Lunar Orbit Rendezvous

• CEV to Lunar Orbit, Lunar Orbit Rendezvous for
  Return

Laura Condon Jason Herrera JoHanna
Przybylowski Nabori Santiago Henry Wong On
Systems Team
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Functional Flow Diagram
Architecture Name Nabori Santiago
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Functional Flow, cont
Architecture Name Nabori Santiago
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Functional Flow, cont
Architecture Name Nabori Santiago
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Interfaces Undocking/Docking
Architecture Name Presenter Name
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Interfaces Descent/Ascent
Architecture Name Presenter Name
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Interfaces Surface Stay
Architecture Name Presenter Name
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Architecture Risks

• Added complexity from two vehicles
• May require multiple launches assembly in earth
  orbit
• Interface between Lander and CEV
• Lander must have full set of subsystems
• Undocking and Rendezvous
• Danger of Collision
• Ineffectual Docking
• Communications Blackout
• Diminished Abort Capability
• Must dock with CEV before return to earth

Architecture A JoHanna Przybylowski
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System-level Trades
Architecture Name Presenter Name
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System Drivers
Architecture Name Presenter Name
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Delta V Estimate

• Assumed phases of flight
• Trans-lunar injection
• Injection corrections
• Lunar orbit insertion
• Lander Descent/Ascent
• Trans-earth injection
• Lander Delta V calculated using 0th order rules
  of thumb for landing from orbit
• Typical delta v numbers used for other phases of
  flight
• Assumed 200 km LEO departure/arrival orbit
• Assumed 100 km lunar arrival/departure orbit
• Assumed typical bipropellant Isp (320 s)
• Total Delta V 7,751 m/s

Architecture A Henry Wong
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Mass Estimate

• Used Method in HSMAD chapter 12 for estimating
  dry mass of Lander CEV
• Assumed
• CEV can be scaled back to roughly the size of the
  space shuttle for a lunar mission (10m3/person,
  4 people, 2 week mission duration)
• 1 metric ton of cargo taken to lunar surface and
  left there
• Bottom Line System Mass in LEO 137 metric tons

Architecture A Henry Wong
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System Mass In LEO
Architecture A Henry Wong
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Mars Back Assessment

• Lander currently has 3700 m/s of total delta V
  capability
• Need 4000 m/s for Mars ascent alone
• Lander sized to carry 1 metric ton of cargo
• Need 7 metric tons capability for Mars
• This architecture will very likely keep the
  Lander mass below 35 metric tons
• Thrust to Weight ratio requirement should be
  achievable with good propulsion design
• With these requirements, system mass in LEO
  increases to 275 metric tons

Architecture A Henry Wong
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More info Needed

• CEV and Lunar Habitat design and specifications
• CEV docking hatch
• Communications capabilities
• Other considerations
• Current technological capabilities
• Guidance systems
• Communication systems
• Power Generation and Thermal Protection
• Abort capability requirements

Architecture A Henry Wong
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Architecture 2 Lunar Direct

• CEV to lunar surface,
• direct return

Finale Doshi Chris Pentacoff William
Peters Nick Sidelnik Regina Sullivan On
Systems Team
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Mission Sequence
7. Re-entry with aero-braking
2. In lunar SOI inclination change to land at
desired site
1. Systems checks and small inclination change
in LEO
3. Landing burn
4. Surface stay
5. Launch to lunar orbit (if needed)
6. Moon-Earth transfer burn
Lunar Direct Chris Pentacoff
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System-Level Trades
Lunar Direct Chris Pentacoff
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System Drivers
Lunar Direct Chris Pentacoff
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Propulsion and DeltaV

• Design Drivers Unique To Architecture
• Engine must have enough thrust to lift entire
  craft from the lunar surface, as well as
  performing orbit injections (an overall delta-v
  of 11 km/s)
• Primary engine needs to be throttle-able
• Trades
• Specific impulse vs. maximum thrust
• Single vs. multiple stages
• Hydrogen and lox vs. methane and lox
• More fuel gives greater safety factor in case of
  abort but adds mass
• Toxic but powerful fuels vs. safe and reliable
  ones

Lunar Direct Chris Pentacoff
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Structures and Mechanisms

• Design Drivers Unique to Architecture
• Vehicle size, weight, staging, subsystem
  distribution
• Trades
• Vehicle shape Tall and thin vs. short and wide
• Staging Use Earth-moon transit engine for
  descent vs. drop this engine before descent
• Modules Subsystem distribution among vehicle
  modules may influence vehicle configuration

Lunar Direct Nick Sidelnik
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Power, Thermal, Life Support

• Architecture B unique attributes
• Single habitat without repetitive subsystems
• Economies of scale reduces mass
• Life Support Single system to support 36
  man-days
• Power Single power source-Minimum 80 Kwatts
• Thermal
• Larger system scale means heavier thermal loads
• Multiple return stages means multiple cooling
  systems
• Landing with heat shield means larger mass
• Larger amount of return fuel to store

Lunar Direct Nick Sidelnik
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Comm. and GNC

• Design Drivers Unique to Architecture
• Only need one central communication unit.
• One system in all environments affects antenna
  design.
• No orbiting section to use as relay station.
• Whole mass of system stays together requires
  higher thrust from control system to make
  changes.
• Larger landing mass requires more fuel if landing
  selection range is not to decrease.
• Only need to worry about one system.
• Trades
• Communication satellite available vs. onboard
  system
• One system vs. more compex control

Lunar Direct Nick Sidelnik
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Mass and Power Estimates

• Estimated masses of individual subsystems based
  on class readings
• Assumed
• Assumed a 12-day mission
• 1 metric ton of cargo taken to lunar surface and
  left there
• Bottom Line System Mass in LEO 300 metric tons

Lunar Direct Will Peters
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Mass and Power Estimates
Lunar Direct Will Peters
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Overview of Risks

• Landing a large module presents
• a need for sophisticated attitude control
• greater tipping hazards
• fuel explosion hazards
• Having a one-part system requires
• extra redundancy for the habitation module
  (split into parts)
• back-up plans if propulsion or power systems are
  damaged

Lunar Direct Will Peters
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Mars-Back Assessment

• Delta-V
• Delta-V required for transport from LEO to lunar
  surface is approx. equivalent to delta-V required
  for transport from Mars orbit to Martian surface
  ( 5400 m/s vs. 4100 m/s)
• Vehicle Mass
• Lunar-direct architecture will likely have
  greatest vehicle mass large mass may be
  acceptable for lunar mission but not for Mars
  (Mtotal for Mars lt 35 metric tons)
• Vehicle Structure/Configuration
• Increased gravity on Mars will affect loading on
  structure, other issues (e.g. crew exit from
  vehicle)

Lunar Direct Will Peters
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More info Needed

• Lunar Habitat specifications
• Power availability
• Radiation shielding availability
• Communications support
• Current technological capabilities
• In-Situ propellant production
• Alternative Power Generation Options
• Abort capability requirements (is safe haven
  adequate?)

Lunar Direct Will Peters