Rationale of NASA Lunar Precursor Robotic Program (LPRP)

… for the VSE

(vs. I don’t need nuthin’ but a map)

Jeff Plescia, Ben Bussey, Paul Spudis, Tony LavoieApplied Physics Laboratory, Johns Hopkins University

Marshall Space Flight Center

October 23, 2007ILEWG Meeting

Considerations

Objective: Establishment of outpost site for long-term occupation.“…sustained human presence on the Moon…”

Environmental considerations (lighting, thermal) may be paramount.

Resource potential may be important.

Scientific objectives not likely to be a driver.

International cooperation, commercial ventures, ….

Different from Apollo and Mars robotic missions.

Raison d’etre for lunar outpost must be established.It defines what characteristics are important.

Environment

Spatially Independent:

Regolith physical propertiesChemistry (major element)DustSurface disturbance on landingRock frequencyRadiationMicrometeoroidsMagnetic field***Atmosphere**Surface charging / levitated dust*

Spatially Dependent:

LightingThermalTopographyCommunication / Earth ViewResourcesScienceCommerceFlight

Precision landingDelta V budgetApproach over shadowed terrain

These are the site discriminators.

What Really Needs to Be Measured at the Moon?Risk Reduction / Cost Control / Optimization

Apollo-like Sortie Polar

Geodetic control – enabling Topography - enablingHigh-resolution imaging (hazards) - enhancing

Non-PolarNothing – enabling High-resolution imaging (hazards) - enhancing

Outpost – Being There (Just land safely)Polar

Topography - enablingGeodetic control – enablingLighting model – enhancingHigh-resolution imaging - enhancing

Non-PolarNothing – enabling High-resolution imaging – enhancing

GlobalDust toxicity – TBD Electrical charging – TBD

Regolith Physical Properties

Apollo 16: Station 10 ALSEP

Blowing Regolith - Apollo LM DescentApollo 11

Initiate: 73-33 m (240-110’)75% Obscuration at TouchdownMaterial moved along surface – deflected by rocks

Apollo 12Initiate: 53 m (175’)Obscuration 12 m (40’)Surface altered below 9-12 m altitude

Apollo 14Initiate: 33 m (110’)Erosion of 10 cm 1 m SE of nozzle

Apollo 15Initiate: 45 m (150’)Obscuration 18 m (60’)

Apollo 16Initiate: 25 m (80’)Block and small crater visible to surface

Apollo 17Initiate: 20 m (65’)No obscurationEvidence of plume interaction with surface across 50 m

AS11-40-5920 AS12-47-6906 AS14-66-9261

The amount of material disturbed by the LM descent engine is a strong function of the approach trajectory and speed. Oblique trajectory causes the least disturbance of the surface. Vertical descent ( A15) caused the most disturbance.

DustDust: <50 µm size fraction

consists largely of impact produced glasscomplicated shapes, jagged edges, large surface area<20 micron size fraction: 20 wt % of soil

Different composition from bulk regolith.

Impact generated glass and nano-phase Fe increase with decreasing grain size.~80 wt. % at sizes <10 micron

Taylor et al. (2007) and Liu et al. (2007) data on size-frequency distribution of dust-sized material (20 microns-20 nm).

Two samples 10084-70051 both display peaks at 100-200 nm>95% are <2 micronA11-10084: 50% of particles are <0.1 micronA11-10084: >40% ultrafine (<100 nm) particlesA17-70051: 50% of particles are <0.3 micron

What Really Needs to be Measured at the Moon?

Outpost with Resource UtilizationResource distribution (ore characterization)

H form, concentration, distribution in polar regions (lighted and shadowed)

Highlands compositionPyroclastic compositionRegolith physical properties

Pyroclastic depositsPermanently shadowed

PolarTopography - enablingGeodetic control – enablingLighting model – enhancingHigh-resolution imaging - enhancing

Non-PolarHigh-resolution imaging – enhancing

GlobalDust toxicity – TBD Electrical charging – TBD

Lunar Robotic Precursor Program

Undertake robotic lunar exploration missions that will return data to advance our knowledge of the lunar environment and allow United States (US) exploration architecture objectives to be accomplished earlier and with less cost through application of robotic systems. LPRP will also reduce risk to crew and maximize crew efficiency by accomplishing tasks through precursor robotic missions, and by providing assistance to human explorers on the Moon.

Orbital mapping and reconnaissance with Chandrayaan, LRO, et al.

Probing the surface with impactors (LCROSS)

….

Exploring and prospecting future habitation sites with surface landers and rovers

Emplacing orbital communications and navigation assets to support future missions

Which Resources Are Important?

Apollo 11 soil Apollo 16 soil Mare Highlands

H 20-100 ppm 4-40 ppm

He* 19-80 ppm 3-35 ppmAr 1.3-12 ppm 0.7-3 ppmXe 0.5-3.8 ppm 0.2-1 ppm

C 100-200 ppm 30-280 ppmN 20-80 ppm 4-200 ppmK 1000-1800 ppm 380-1100 ppmP 480-650 ppm 130-1100 ppm

S 660-1500 ppm 470-640 ppmF 75-520 ppm 27-105 ppmCl 3-40 ppm 12-270 ppm

* 4He/3He = ~ 2500

One cubic meter (1 m3) of lunar regolith contains enough hydrogen, carbon, nitrogen, potassium, and other trace elements to make lunch for two – two cheese sandwiches on rye, two colas (flavored with real sugar, although there’s enough Cl to sweeten it with Splenda instead), and two large plums.

(credit: Larry Taylor)

Water ice in shadowed regions of both poles

Extract oxygen, metals from lunar materials for construction, propellant

Recover solar-wind gases (e.g., hydrogen and other volatiles) implanted on lunar regolith

Collect solar energy with photoelectric arrays built from lunar materials and beam energy to Earth or cislunar space

Resource Exploitation –Data for Decision in the Critical Path

Polar

Objectives:

Find and characterize resources that make exploration affordable and sustainable

Lunar volatiles (e.g., H)Sunlight

Landing site morphologyPhysical PropertiesDustOxidation PotentialRadiation Environment / Shielding

Field test new equipment, technologies and approaches (e.g., dust and radiation mitigation)

Support demonstration, validation, and establishment of heritage of systems for use on human missions

Gain operational experience in lunar environmentsProvide opportunities for industry, educational and

international partners

Gaddis et al. 2003

Pyroclastic deposits have high H contentApollo 17 orange glass and Apollo 15 green

glass highly enriched in volatile elementsBlack glass contains illmenite – enhanced H

retention

Pyroclastic Deposits

Resources - H

Elphic modeling voodoo – Using radar topography, calculate shadowed areas, allow illuminated regions to have up to 200 ppm H, shadowed areas have whatever is necessary to match neutron signature.

Concentration is a function of shadow area and whether H is uniformly distributed. Concentrations could be higher if shadowed areas not uniformly filled.

Resources - Ice?

Clementine Bi-Static ExperimentMargot et al. Earth-based radar

Polar Light MissionOverviewDevelop common lander to land in sunlight near lunar

pole to characterize environment and depositsLander becomes standard design for delivery of future

payloadsSunlight mission answers first-order questions about

poles and provides ground truth for orbital sensing

Concept of Operations

Precision landing & hazard avoidanceCharacterize sun illumination over a seasonal cycleDirect measurement of neutron flux, soil hydrogen

concentration in sunlit area for correlation with orbital mapping

Biological radiation response characterizationCharacterize lunar dust and charging environmentPossible micro-rover for near-field investigation (if

funded separately)Picture/Diagram

Polar Dark Mission

Concept of Operations

Rover delivered directly to the crater floor by the lander (which expires shortly after rover egress)

Rover traverses to selected sites obtaining ground penetrating radar and neutron spectrometer profiles along the way

Sampling at predetermined site, rover drills and samples material approximately every 50 cm to a maximum depth of 2 m

On-board analysis of volatile content and composition

OverviewReference concept: fuel cell-powered rover, ranging > 25 km and obtaining > 22 subsurface measurements (each 1,000

m apart) to map and analyze polar volatilesNavigation by integration of coherent ranging with an overhead relay satellite, IMU, and perhaps terrain relative

navigationNavigation by flash lamps and MER style hazard avoidance or 3-D scanning LIDARRTG-powered options are lighter and offer extended life, but are more costly

Green – NS pixelsRed – High Radar CPROrange – “Permanent” sunlightBlue line – Rover traverse

Dawes Crater

Shadow in Earth-based radar images is Earth-shadow; entire crater floor is in sun-shadow

Polar Dark Rover

Lander / Rover Concepts

ISRU Excavation Rover 1/10th scale demo

0200400600800

1000120014001600180020002200

2000 3000 4000 5000 6000 7000 8000 9000 10000

Injected Mass (kg)

Payl

oad

Land

ed M

ass

(kg)

Arch. 1 Arch. 3 Arch. 6 Arch. 7 Arch. 9C Arch. 9H Arch. 10 small cryo

RLEP-2 Lander Performance Summary

MSL

Range of values represents range of payload capacity depending on:• Trajectory approach• Mass growth from CBE (0-25%)• Whether relay satellite is co-launched (Architectures 1,9)• Propulsion selected for lander• Whether lander hops out of crater (Architecture 10)

Note: Added battery mass specific for crater rim mission during eclipse is counted as payload mass for this comparison (130 - 156 kg)

Off Graph:• Surveyor (1006, 41)• MER (1063, 174)• Apollo 15 (46,838, 4971) (Assumes ascent vehicle is landed payload)

Delta IV H (9615 kg)Atlas 551

(6560 kg)

Atlas 401(3580 kg)

Direct Landing, Hypergol + Solid

Orbit First, Hypergol

Orbit First, C

ryogenic

Luna/Lunokhod 1

Luna/Lunokhod 2

Viking

645

430, 450

1351

888

565614

987

917

2003

1326

1622

724

296

LAT

Summary

Precursor robotic missions to the Moon Better define the environment

Reduces riskIncreases efficiencyResource trades (e.g., proximity to sunlight for power and water for fuel)

Don’t want to have to move the outpost.

Most important objectives:Characterize new or poorly understood

processes and environments (e.g., lunar poles)

Pre-reconnaissance of targets for future human exploration

Resource prospecting

Robotic missions have other important programmatic uses beyond science; scientific exploration can be opportunistic

Robotic Precursor Missions

Robotic missions:Provide early strategic information for human missions

Key knowledge needed for human safety and mission successInfrastructure elements for eventual human useData will be used to plan and execute human exploration of the

Moon

Resolve the unknowns of the lunar polar regionsKnowledge of the environment – temperature, lighting, etc.Resources/deposits – composition and physical natureTerrain and surface properties - dust characterizationEmplace support infrastructure – navigation/communication,

beacons, teleoperated robots

Make exploration more capable and sustainableEmplace surface systemsDemonstrate new technologies that will enable settlementOperational experience in lunar environmentCreate new opportunities for scientific investigation

“Starting no later than 2008, initiate a series of robotic missions to the Moon to prepare for and support future human exploration activities” (NSPD-31)