human lunar exploration mission architectures · • robotic explorers will visit new worlds first,...

Not for Distribution - Pre-Decisional1 1 March 2004LPI Workshop

Human Lunar Exploration Mission Architectures

LPI Lunar Knowledge Requirements Workshop

March 1-2, 2004


Guiding Principles for Exploration(excerpt NASA “New Space Exploration Vision”, January 14, 2004)

♦ Employ Human and Robotic Capabilities• NASA will send human and robotic explorers as partners, leveraging the

capabilities of each where most useful. • Robotic explorers will visit new worlds first, to obtain scientific data,

demonstrate breakthrough technologies, identify space resources, and send tantalizing imagery back to Earth.

• Human explorers will follow to conduct in-depth research, direct and upgrade advanced robotic explorers, prepare space resources, anddemonstrate new exploration capabilities


Program Element Interrelationships

TechnologyBuilding BlocksMission ArchitecturesPotential Destinations

and Science Objectives

Efficient In-Space Prop..Efficient In-Space Prop..AeroassistAeroassist

Low-cost EnginesLow-cost EnginesCryo Fluid

ManagementCryo Fluid ManagementRobust/Efficie

nt PowerRobust/Efficient PowerLightweight

structures systems, sensors, micro/nanoelectronics

Lightweight structures systems, sensors, micro/nanoelectronics

MissionAnalyses

Technology Development Requirements

Robotic Precursor Missions

For NASA Internal Use Only - Pre-Decisional49 16-Feb-04JSC/EX/Code T Visit

MOONMOON

EARTHEARTH

EarthOrbit

Crew TransferCrew

Transfer

Pre-deploy Propellant


Return SEPs

Return SEPs

Architecture ElementsArchitecture Elements

SEP Freighterx 2

CEV + Power & Propulsion Module

x 1 per mission

CEV Reused?

Reference Lunar Operations Concept #4Fully Reusable

Trade:Lunar Orbit or Lunar L1

Space-Based Lander,

Propellant Transfer

Space-Based Lander,

Propellant Transfer

Crew Launch

Propellant Transfer

Propellant Transfer

Normal Mission

Earth Return

Normal Mission

Earth Return

LEO Prop Depotx 1

Lunar Lander/CEVx 1

Launch Vehicle Trade Study

Required


Required

Abort Capacity

Evolution to Mars

Technology

Evolution to Mars

Technology

Evolution to Mars

Element Normal MissionNormal Mission

Emergency Return

Emergency Return

Robotic Precursor Mission

Requirements

• Acquire data sets• Human safety• Engineering

• Demonstrate key technologies

• Deliver Infrastructure


MOONMOON

EARTHEARTH

EarthOrbit

Crew TransferCrew

TransferPre-deploy Lander

Pre-deploy Lander

Earth ReturnEarth

Return

Return SEP

Return SEP


SEP Freighterx 1


x 1 per mission

Lunar Landerx 1 per mission Power &

Propulsion Module Expended

CEV Reused?

Expended

Reference Lunar Operations Concept #3Lunar SEP Tug

Crew Launch


Injection Stagex 1 per mission


Required


Required

Option for ReusabilityOption for

Reusability

Abort Capacity

Evolution to Mars

Technology

Evolution to Mars

Element

Evolution to Mars

Element


Lunar Landerx 1 per mission

Reference Lunar Operations Concept #2LEO Depot

MOONMOON

EARTHEARTH

EarthOrbit

Earth ReturnEarth

Return




x 1 per mission

Expended

Power & Propulsion Module Expended

CEV Reused?

LEO Prop Depotx 1

Prop Transfer

Prop Transfer

Option for ReusabilityOption for

Reusability

Crew Launch



Required


Required

Abort Capacity

Evolution to Mars

Technology

Evolution to Mars

Element

Evolution to Mars

Element


Reference Lunar Operations Concept #1Lunar Basic

MOONMOON

EARTHEARTH

EarthOrbit

Crew TransferCrew

Transfer

Earth ReturnEarth

Return

Pre-deploy Lander

Pre-deploy Lander




x 1 per mission


Expended

Expended


Expended

CEV Reused?

Crew Launch



Required


Required

Abort Capacity

Evolution to Mars

Element

Evolution to Mars

Element


Recent Exploration Architecture Studies

Office of Exploration

♦ 1988 Case Studieso Human Expedition to Phoboso Human Expedition to Marso Lunar Observatoryo Lunar Outpost to Early Mars Evolution

♦ 1989 Case Studieso Lunar Evolutiono Mars Evolutiono Mars Expedition

Advanced Development Office

♦ Mars Exploration Missionso Design Reference Mission Version 1.0 - 1994o Design Reference Mission Version 3.0 - 1997o Design Reference Mission Version 4.0 - 1998o Mars Combo Lander (JSC) - 1999o Dual Landers – 1999

♦ Decadal Planning Team / NEXT - 2000-2002o Earth’s Neighborhood Architectureo Asteroid Missionso Mars Short and Long Stayo NEP Artificial-gravity

♦ Exploration Study 1 – 2002-2003o Earth’s Neighborhood Architectureo Lunar Oasis (RASC)

♦ Special Studies 2003o Lunar Architectures Supporting

o Comptroller/Space Architecto Comptroller/Code M

Lunar & Mars Program Office

♦ NASA 90-Day Study – 1989o Approach A – Balance and speedo Approach B – Earliest possible Mars landingo Approach C – Reduced Earth logisticso Approach D - Relaxed mission dateso Approach E – Reduced scale

♦ “The Synthesis Group” – 1991o Mars Explorationo Science Emphasis for the Moon and Marso The Moon to Stay and Mars Explorationo Space Resource Utilization

Exploration Programs Office

♦ First Lunar Outpost – 1993

♦ Early Lunar Resource Utilization – 1993

♦ Human Lunar Return - 1996


Example Near-Earth Mission Trade Space

1988 “Lunar Observatory”1988 “Lunar Outpost”1989 “Lunar Evolution”1990 “90-Day Study”1993 “First Lunar Outpost”1993 “Lunar Resource Utilization”1996 “Human Lunar Return”2000 “Earth’s Neighborhood”2002 “Exploration Study #1”

1988 “Lunar Observatory”1988 “Lunar Outpost”1989 “Lunar Evolution”1990 “90-Day Study”1993 “First Lunar Outpost”1993 “Lunar Resource Utilization”1996 “Human Lunar Return”2000 “Earth’s Neighborhood”2002 “Exploration Study #1”

Launch VehicleCapability

LEO Assembly?

Duration ofSurface Stay

High Degree ofTransportation

Element Reuse?

Small (<35 mt)Proton, EELVs ShuttleSmall (<35 mt)Proton, EELVs Shuttle

Medium (60-100 mt)Shuttle-C, Shuttle-Z, MagnumMedium (60-100 mt)Shuttle-C, Shuttle-Z, Magnum

Large (100+ mt)Heavy Lift Launch VehicleLarge (100+ mt)

Heavy Lift Launch Vehicle

NoNo

<14 DaysLive in Lander<14 DaysLive in Lander

14-45 DaysHabitat Lander

14-45 DaysHabitat Lander

YesYesNoNo

YesSpace Station

YesSpace Station

45+ DaysOutpost

45+ DaysOutpost


Lunar Mission Design

♦High level program groundrules & constraints can have significant implications for system operational characteristics

♦ For “Project Constellation” these G & Cs include:• Launch capacity• Lunar surface access requirements (lunar latitude)• Surface mission duration

♦ The operational impacts include:• Crew return opportunity frequency• Abort practicality• Overall minimum mission duration• System mass & performance


Lunar Injection Constraints

Moon’s Antipode at Lunar Arrival

(Point of TLI)

Moon at Lunar ArrivalLunar Orbital Motion ~13o/day Posigrade

Earth Parking Orbit ~5 deg/day Nodal

Regression

♦ Assumptions• Lunar mission will involve multiple launches with aggregation in

LEO• Crew launched to LEO

♦ Operational Implications• Combination of LEO nodal regression and lunar motion

provides lunar injection opportunities ~ every 9 days• Lighting conditions at a given landing site will vary greatly from

one opportunity to the next• Vehicle performance, “wait” times in earth and lunar orbit will

need to be traded against operational flexibility

Injection Window #1

Injection Window #2

Injection Window #3

SUN

Lunar “Morning” at Site

Lunar “Afternoon” at Site

Lunar Night at Site

Lunar Orbital Motion


Landing Site Restrictions for Lunar Orbit Rendezvous (LOR)

Region of unattainable landing sites

Region of unattainable landing sites

All landing sites available

Equatorial Parking OrbitIn-plane lunar descent/ascent available every 2 hours for equatorial landing sites; all non-equatorial sites unavailable

Mid-Inclination Parking OrbitIn-plane lunar descent/ascent available every 25-27 days for landing site latitudes less than orbit inclination; all higher latitude sites unavailable

Polar Parking OrbitIn-plane lunar descent/ascent available every 2 hours for polar landing sites or every 14 days for non-polar sites

Orbiting Spacecraft

♦Assumptions• Access to non-equatorial landing site will be desired• Lunar stay time of more than a few days will be desired

♦Operational Implications• High-latitude lunar landing sites will imply high inclination lunar parking orbits (assuming LOR)• “Free-Return” transits probably not practical• Lunar decent/ascent to high-latitude site available once every ~ 14 days from lunar polar orbit• Descent/ascent to polar site available every 2 hours from polar orbit


Earth Return Restrictions fromLunar Polar Orbit

TEI V∞

TEI V∞

TEI V∞

TEI V∞

Moon to Earth TransferMoon’s Mean Motion:~13.2o/day

Moon to Earth Transfer

Day 0:Minimum-Energy TEI is Available on Pass Under MoonTEI ∆V = 848 m/s

Day 0:Minimum-Energy TEI is Available on Pass Under MoonTEI ∆V = 848 m/s

Day 7:Non-Regressing Polar Orbit is 90o from the desired TEI orientation3-Impulse ∆V = 2015 m/s


Day 14:Minimum-Energy TEI is Available on Pass Over MoonTEI ∆V = 848 m/s

Day 14:Minimum-Energy TEI is Available on Pass Over MoonTEI ∆V = 848 m/s



♦ Assumptions• Access to non-equatorial landing

site will be desired• Lunar stay time of more than a

few days will be desired♦ Operational Implications

• Trans-Earth Injection from Lunar Polar Orbit only available every ~ 14 days


Earth-Moon L1 Characteristics

♦Alternative to Lunar Orbit Rendezvous♦Gravitational “Balance Points” in Earth-Moon

System♦L1 Point ~55,000 km from lunar surface

• Weakly unstable – small stationkeeping required♦Synchronization of Earth, Moon, L1, and Lunar

Surface• Continuously open “windows” from L1 to anywhere on

lunar surface and back• Four days from Earth, two days from Moon (high thrust)

Moon’s Orbit

L1 L2L3

L5

L4

L1 326740 57660L2 449748 65348L3 380556 764956L4 384400 384400L5 384400 384400

Distance from Earth’s Center (km)

Distance from Moon’s Center (km)

Crew departs from LEO

L1

Crew Exploration

Vehicle

Lunar Lander


Summary of Lunar Mission Design Constraints

From Low-inc orbit: Every 2 hrFrom Mid-inc orbit: Every 27 dFrom Polar orbit: Every 14 d

From LEO: Every 9-12 d

From Low-inc orbit: N/AFrom Mid-inc orbit: N/AFrom Polar orbit: Every 2 hr

From Low-inc orbit: N/AFrom Mid-inc orbit: N/AFrom Polar orbit: Every 14 d

From Low-inc orbit: N/AFrom Mid-inc orbit: Every 27 dFrom Polar orbit: Every 14 d

Outbound to Moon Ascent/Descent Return to Earth

» Lunar Orbit Rendezvous «

Low Latitude Landing Sites(e.g. Sea of Tranquility)

Mid-Latitude Landing Sites(e.g. Tycho, Imbrium)

Polar Landing Sites(e.g. SP-Aitken Basin)

From LEO: Every 9-12 dAscent/Descent Windows Continuously Available

Outbound to Moon Ascent/Descent Return to Earth

» Libration Point Rendezvous «

Earth Return Windows Continuously Available

Low Latitude Landing Sites(e.g. Sea of Tranquility)

Mid-Latitude Landing Sites(e.g. Tycho, Imbrium)

Polar Landing Sites(e.g. SP-Aitken Basin)

Declination of the Moon Relative to EPO

-60

-40

-20

0

20

40

60

0 20 40 60 80 100 120

Tim e (days)

W indow Ever y 3-12 days


-60

-40

-20

0

20

40

60

0 20 40 60 80 100 120

Tim e (days)



-60

-40

-20

0

20

40

60

0 20 40 60 80 100 120

Tim e (days)



-60

-40

-20

0

20

40

60

0 20 40 60 80 100 120

Tim e (days)



-60

-40

-20

0

20

40

60

0 20 40 60 80 100 120

Tim e (days)



-60

-40

-20

0

20

40

60

0 20 40 60 80 100 120

Tim e (days)



-60

-40

-20

0

20

40

60

0 20 40 60 80 100 120

Tim e (days)



-60

-40

-20

0

20

40

60

0 20 40 60 80 100 120

Tim e (days)


From Low-inc orbit: Every 2 hrFrom Mid-inc orbit: Every 27 dFrom Polar orbit: Every 14 d

From Low-inc orbit: N/AFrom Mid-inc orbit: Every 27 dFrom Polar orbit: Every 14 d

Global access reqt results in surface stay

times of ≥14 days

Global access reqt results in surface stay

times of ≥14 days

No surface stay time constraintsNo surface stay time constraints


Comparison of Staging Strategies(assumes mid to high latitude landing)

No RestrictionsLimited to 14-day

Increments(e.g. 14, 28, 42 days, etc.)

Surface Stay Time, Mid-Latitude Sites

No RestrictionsNo RestrictionsSurface Stay Time, Polar Sites

Representative Scale of Single-Stage Lander Vehicle

Libration Point Rendezvous

Lunar Orbit Rendezvous

95# of Major Propulsive ManeuversAnytimeEvery 13.6 daysEarth Return Frequency

YesNoAnytime Abort from Lunar Surface Available?

YesNoFree Return Abort (Post-TLI) Available?

~5,600 m/s~4,400 m/sLargest Single-Leg ∆V10,700 m/s9,400 m/sTotal Mission ∆V


Lunar Surface Mission Activity Space

0

5

500

100

50

10

0

surface access and short term habitationaugmented power and thermal

base power and long term habitationlab and dedicated test/experiment equipment

5 14 28 700Surface Mission Duration (days)

Rad

ial D

ista

nce

from

Lan

ding

Site

(kilo

met

ers)

Simulation“Short Stay”Mars Mission

• EVA systems• Operations

Apo

llo

Simulation“Long Stay”Mars Mission

• Life support• Habitation• Power• EVA systems• Operations• Integrated

testing• ISRU

Reconnaissance• South Pole• Aristarcus• Taurus-Littrow• 8 Seismometers

Long Term Research• South Pole• Aitken Basin• Aristarcus• Mare Smythii


Exploration Life Science Issues

♦ Lunar• Crew Radiation Protection (Solar Particle Events)

– Apollo essentially trusted to luck– At least one solar particle event occurred between Apollo missions which, if it had

occurred during a mission would have represented a severe crew health issue (orfatalities)

– Analysis capability coming on-line to rapidly assess design concepts for SPE attenuation characteristics

♦ Mars• Same as above plus Galactic Cosmic Radiation• Long-duration microgravity exposure

– Countermeasures– Artificial-g


Operations Concept #1 Description

♦Overview• Flight elements launched wet, rndz/dock in LEO (depending on launch vehicle

capacity)• Potential Advantages

– Minimize transportation technology development and on-orbit operations complexity for early lunar exploration capability

• Potential Challenges– All flight elements must provide autonomous flight functions (e.g. power, thermal, attitude

control, orbit maintenance, propellant management)– Sensitive to disruption in launch campaign– Largest launch capacity requirements– Highly sensitive to launch vehicle capacity– Little potential for eventual reusable elements

♦Potential Reusable Elements• CEV

♦Applicability to Mars• Cryogenic Propellant Storage• Autonomous Rendezvous & Capture• Lunar Lander System Heritage for Mars Lander• Injection Stage for Chemical Mars Injection


Reference Lunar Operations Concept #1Lunar Basic

MOONMOON

EARTHEARTH

EarthOrbit

Crew TransferCrew

Transfer

Earth ReturnEarth

Return

Pre-deploy Lander

Pre-deploy Lander




x 1 per mission


Expended

Expended


Expended

CEV Reused?

Crew Launch



Required


Required

Abort Capacity

Evolution to Mars

Element

Evolution to Mars

Element


LEO Propellant AggregationOperations Concept #2 Description

♦ Overview• Decouples hardware and propellant ETO launches through on-orbit propellant

aggregation and transfer at LEO Prop Depot• Vehicles berthed/assembled at Depot• Potential Advantages

– LEO Depot “decouples” launch campaign– Flexibility in launch vehicle capacity (offloaded flight elements)– High launch vehicle packaging efficiency– Option of reusability of Injection Stages enabled

• Potential Disadvantages– LEO infrastructure element required– Extended times for flight elements in MMOD environment– Additional technology development

♦ Potential Reusable Elements• CEV• Injection Stages• LEO Cryo Depot

♦ Applicability to Mars• Cryogenic Propellant Storage, Gauging, and Transfer• Autonomous Rendezvous & Capture• Lunar Lander System Heritage for Mars Lander• Injection Stage for Chemical Mars Injection



Reference Lunar Operations Concept #2LEO Depot

MOONMOON

EARTHEARTH

EarthOrbit

Earth ReturnEarth

Return




x 1 per mission

Expended


CEV Reused?

LEO Prop Depotx 1

Prop Transfer

Prop Transfer

Option for ReusabilityOption for Reusability

Crew Launch



Required


Required

Abort Capacity

Evolution to Mars

Technology

Evolution to Mars

Element

Evolution to Mars

Element



♦ Overview• Replaces Injection Stage’s Lander delivery function with reusable, high-efficiency

solar electric propulsion• SEP Stage provides long duration vehicle health maintenance• Potential Advantages

– Reuse of high-value vehicle– Reduced launch mass requirements

• Potential Challenges– Infrastructure element required – high performance, reusable propulsion system– Reusable lander design issues– Extended times for flight elements in MMOD environment– Additional technology development

♦ Potential Reusable Elements• CEV• Lander• SEP Stage

♦ Potential Applicability to Mars• Sub-scale Solar Electric Propulsion Stage• Thrusters for NEP Transfer Vehicle• Cryogenic Propellant Storage• Autonomous Rendezvous & Capture• Lunar Lander System Heritage for Mars Lander• Injection Stage for Chemical Mars Injection


MOONMOON

EARTHEARTH

EarthOrbit

Crew TransferCrew

TransferPre-deploy Lander

Pre-deploy Lander

Earth ReturnEarth

Return

Return SEP

Return SEP


SEP Freighterx 1


x 1 per mission

Lunar Landerx 1 per mission Power &

Propulsion Module Expended

CEV Reused?

Expended

Reference Lunar Operations Concept #3Lunar SEP Tug

Crew Launch




Required


Required

Option for ReusabilityOption for Reusability

Abort Capacity

Evolution to Mars

Technology

Evolution to Mars

Element

Evolution to Mars

Element



♦ Overview• Fully reusable elements• Propellant transfer via SEP tugs (applicable for either Earth- or lunar originating

propellants)♦ Potential Reusable Elements

• All elements are reusable♦ Potential Applicability to Mars

• Same as previous Operations Concepts, but adds full reusability of all elements, and potential full-scale use of lunar resources


MOONMOON

EARTHEARTH

EarthOrbit

Crew TransferCrew

Transfer



Return SEPs

Return SEPs


SEP Freighterx 2


x 1 per mission

CEV Reused?

Reference Lunar Operations Concept #4Fully Reusable


Space-Based Lander,

Propellant Transfer

Space-Based Lander,

Propellant Transfer

Crew Launch

Propellant Transfer

Propellant Transfer

Normal Mission

Earth Return

Normal Mission

Earth Return

LEO Prop Depotx 1

Lunar Lander/CEVx 1


Required


Required

Abort Capacity

Evolution to Mars

Technology

Evolution to Mars

Technology

Evolution to Mars

Element Normal MissionNormal Mission

Emergency Return

Emergency Return


Mission Architecture Implications to Robotic Lunar Precursors

♦ From the standpoint of lunar surface activities, the Operations Concept chosen is transparent.

♦ Drivers:• Surface destination: polar, equatorial, mid-latitude, (far side)• Surface duration• Surface activities• Use of resources

♦ Orbital reconnaissance/technology demonstration/infrastructure:• Lunar topography at scales relevant to human surface activities, particularly in shadowed

regions at high latitudes.• Lunar surface and near-subsurface resources, including the abundance and nature of water.• Relay communications from the lunar surface to Earth.• Rock populations (~>1 meter) in the vicinity of potential landing sites.• Surface mineralogy and elemental composition at decameter scales, particularly in the polar

regions.• Thermophysical and dielectric properties of the surface layer.• Surface temperature regime in the permanently shadowed craters.• Global lunar gravity field map• Global lunar magnetic field map

♦ Surface reconnaissance/technology demonstration/infrastructure:• Ground-truth verification of landing site characteristics

– (topography, resources, surface engineering properties, geologic properties including mineralogy and chemical composition)

• Test engineering flight and surface operations(landing navigation, precision landing, cold environment operations)

• Test and demonstrate critical technologies(resource utilization, tribology, power, communications, thermal systems)

• Navigation aid to future missions targeted to its landing site.• Characterize the environment in permanently shadowed craters

human lunar exploration mission architectures · • robotic explorers will visit new worlds first,...

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