LCROSSLCROSS

• Our latest mission to the surface of the Moon.

• Developed and managed by NASA Ames Research Center in partnership with Northrop Grumman.

• Goal: to test whether or not water ice deposits exist on the Moon.

• Our latest mission to the surface of the Moon.

• Developed and managed by NASA Ames Research Center in partnership with Northrop Grumman.

• Goal: to test whether or not water ice deposits exist on the Moon.

Why look for water?Why look for water?

• Humans exploring the Moon will need water:– Option 1: Carry it there.– Option 2: Use water that may be there already!

• Carrying water to the Moon will be expensive!

• Learning to “Live off the land”would make human lunar exploration easier.

• Humans exploring the Moon will need water:– Option 1: Carry it there.– Option 2: Use water that may be there already!

• Carrying water to the Moon will be expensive!

• Learning to “Live off the land”would make human lunar exploration easier.

Early Evidence for WaterEarly Evidence for Water

Clementine Lunar Prospector

Two previous missions, Clementine (1994) and Lunar Prospector (1999)

gave us preliminary evidence that there may be deposits of water ice at

the lunar poles.

Clementine bistatic radar - 1994Clementine bistatic radar - 1994

• Circular polarization ratio (CPR) consistent with ice crystals in the south polar regolith.

• Later ground-based studies confirmed high-CPR in some permanently-shadowed craters.

• However, Arecibo scans have also found high-CPR in some areas that are illuminated, probably due to surface roughness.

• Are we seeing ice or rough terrain in dark polar craters?

• Circular polarization ratio (CPR) consistent with ice crystals in the south polar regolith.

• Later ground-based studies confirmed high-CPR in some permanently-shadowed craters.

• However, Arecibo scans have also found high-CPR in some areas that are illuminated, probably due to surface roughness.

• Are we seeing ice or rough terrain in dark polar craters?

Lunar Prospector neutron spectrometer maps of the lunar poles. These low resolution data indicate elevated concentrations of

hydrogen at both poles; it does not tell us the form of the hydrogen. Map courtesy of D. Lawrence, Los Alamos National Laboratory.

Lunar Prospector neutron spectrometer maps of the lunar poles. These low resolution data indicate elevated concentrations of

hydrogen at both poles; it does not tell us the form of the hydrogen. Map courtesy of D. Lawrence, Los Alamos National Laboratory.

Hydrogen has been detected at the poles by Lunar Prospector in 1999. Is it water ice???Hydrogen has been detected at the poles by Lunar Prospector in 1999. Is it water ice???

Lunar Prospector Impact – July 31, 1999Lunar Prospector Impact – July 31, 1999

• South pole impact at end of mission

• Low angle (6.3°), low mass (161 kg), and low velocity (1.69 km/s) less than ideal for water ice detection.

• No water detected.

• Results not conclusive.

• South pole impact at end of mission

• Low angle (6.3°), low mass (161 kg), and low velocity (1.69 km/s) less than ideal for water ice detection.

• No water detected.

• Results not conclusive.

New Evidence for WaterNew Evidence for Water

Data from 3 other probes has now shown that small amounts of water

are widespread across the surface of the Moon. The amount of water

may change during the course of the lunar day.

Deep Impact CassiniChandrayaan-1

Where did we look? Where did we look?

JPL/Goldstone Radar Image

Cabeus

1010

How could there be water at the lunar poles?

How could there be water at the lunar poles?

The Sun never rises more than a few degrees

above the polar horizon so the crater floors are in permanent shadow.

The crater floors are very cold with temperatures of

-238° C (-397° F, 35 K), so water molecules move very slowly and are trapped for billions of years.

Clementine Mosaic - South Pole

Where could water ice come from?Where could water ice come from?

Over the history of the Moon, when comets or asteroids impact the Moon's surface, they briefly produce a very thin atmosphere that quickly escapes into space.

Any water vapor that enters permanently shadowed craters could condense and concentrate there.

Where could water ice come from?Where could water ice come from?

Water molecules at lower latitudes may form from interactions with hydrogen streaming out in the solar wind. These water molecules may get baked out of the lunar soil and can then get trapped in polar craters.

Our Latest Lunar MissionsOur Latest Lunar Missions

Lunar Reconnaissance OrbiterLRO

Lunar Crater Observationand Sensing Satellite

LCROSS

Lunar Reconnaissance OrbiterLunar Reconnaissance Orbiter

• LROC – image and map the lunar surface in unprecedented detail

• LOLA – provide precise global lunar topographic data through laser altimetry

• LAMP – remotely probe the Moon’s permanently shadowed regions

• CRaTER - characterize the global lunar radiation environment

• DIVINER – measure lunar surface temperatures

• LEND – measure neutron flux to study hydrogen concentrations in lunar soil

• LROC – image and map the lunar surface in unprecedented detail

• LOLA – provide precise global lunar topographic data through laser altimetry

• LAMP – remotely probe the Moon’s permanently shadowed regions

• CRaTER - characterize the global lunar radiation environment

• DIVINER – measure lunar surface temperatures

• LEND – measure neutron flux to study hydrogen concentrations in lunar soil

• On-board propulsion system used to capture at the Moon, insert into and maintain 50 km mean altitude circular polar reconnaissance orbit

• 1 year exploration mission followed by handover to NASA science mission directorate

• On-board propulsion system used to capture at the Moon, insert into and maintain 50 km mean altitude circular polar reconnaissance orbit

• 1 year exploration mission followed by handover to NASA science mission directorate

Minimum Energy Lunar Transfer

Lunar Orbit Insertion Sequence

Commissioning Phase, 30 x 216 km Altitude

Quasi-Frozen Orbit, Up to 60 Days

Polar Mapping Phase, 50 km Altitude Circular Orbit, At least 1 Year

LRO Mission Overview LRO Mission Overview

LCROSS Mission ConceptLCROSS Mission Concept

• Impact the Moon at 2.5 km/sec with a Centaur upper stage and create an ejecta cloud that may reach over 10 km about the surface

• Observe the impact and ejecta with instruments that can detect water

• Impact the Moon at 2.5 km/sec with a Centaur upper stage and create an ejecta cloud that may reach over 10 km about the surface

• Observe the impact and ejecta with instruments that can detect water

Excavating with 6.5-7 billion JoulesExcavating with

6.5-7 billion Joules

• About equal to 1.5 tons of TNT

• Minimum of 200 tons lunar rock and soil will be excavated

• Crater estimated to have ~20-25 m diameter and ~3-5 m depth

• Similar in size to East Crater at Apollo 11 landing site

• About equal to 1.5 tons of TNT

• Minimum of 200 tons lunar rock and soil will be excavated

• Crater estimated to have ~20-25 m diameter and ~3-5 m depth

• Similar in size to East Crater at Apollo 11 landing site

LCROSS Mission SystemLCROSS Mission System

• Shepherding Spacecraft: guided and aimed the Centaur to its target and carried all of the critical instrumentation.

• CentaurUpper Stage: provided the thrust to get us from Earth orbit to the Moon and was then used as an impactor.

• Shepherding Spacecraft: guided and aimed the Centaur to its target and carried all of the critical instrumentation.

• CentaurUpper Stage: provided the thrust to get us from Earth orbit to the Moon and was then used as an impactor.

14.5 m

•Visible (263–650 nm) emission and reflectance•spectrometry of vapor plume, ejecta cloud•Measure grain properties•Measure emission H2O vapor dissociation,OH- (308 nm) and H2O+(619nm) fluorescence

UV/Vis Spectrometer

•NIR (1.2–2.4um) emission and reflectance•Spectrometry of vapor plume, ejecta cloud•Measure grain properties•Measure H2O ice features•Occultation viewer to measure water vapor absorption by cloud particles

NIR Spectrometer

•NIR (0.9–1.7 um) context imagery•Monitor ejecta cloud morphology•Determine NIR grain properties•Water concentration maps

NIR Cameras

•MIR (6.0–13.5 um) thermal image•Monitor the ejecta cloud morphology•Determine MIR grain properties•Measure thermal evolution of ejecta cloud•Remnant crater imagery

Thermal Cameras

•Three color context imagery•Monitor ejecta cloud morphology•Determine visible grain properties

Color Camera

•Measures total impact flash luminance•(425–1,000 nm), magnitude, and decay of flash•Sensitive to total volatile soil content, regolith depth and target strength

Flash Radiometer

SpectrometerTelescopes

Save $ and Time by Using an Existing Structure Designed to Carry Heavy

Payloads During Launch

Save $ and Time by Using an Existing Structure Designed to Carry Heavy

Payloads During Launch

EELV Secondary Payload Adapter or ESPA Ring

But how do you make a spacecraft out of something that looks like a sewer pipe?

Put LRO on top

Attach bottom of

ESPA Ring to top of rocket

Use ESPA ring to make

LCROSS spacecraft

Answer: Put Equipment Around the Rim and Tank in the Middle

Answer: Put Equipment Around the Rim and Tank in the Middle

Propellant Tank

ESPA Ring

Solar Array

Equipment Panel (1 of 5)

Integrated LCROSS Spacecraft

Different Panels Perform Different Functions

Different Panels Perform Different Functions

Solar Array

Batteries

Science Instruments

Power Control

Electronics

Command and Data Handling

Electronics (including computer)

Attitude Control and Communications

Electronics

LCROSS Viewed From Above without Insulation

Panel Approach Makes LCROSS Easier to Put Together

Panel Approach Makes LCROSS Easier to Put Together

LCROSS with Panels Laid Flat for Integration of Electronics

Other Equipment Includes Two Types of Antennas to Talk Back to Earth

Other Equipment Includes Two Types of Antennas to Talk Back to Earth

Omni (Low Gain) Antenna (1 on each

side)

Medium Gain Antenna (1 on each side)

And Sensors to Determine Spacecraft Attitude (Pointing)

And Sensors to Determine Spacecraft Attitude (Pointing)

Star Tracker

Sun Sensors (10 total)

Solar Array

Propulsion System Must Maneuver and Point the Spacecraft

Propulsion System Must Maneuver and Point the Spacecraft

Propellant Tank

(40.85” dia)Post

Supports Thrusters

(1 of 4)

5 lb Thruster for

Maneuvers (1 of 2)

1 lb Thruster for Attitude Control

(1 of 8)

Launch: June 18, 2009Launch: June 18, 2009

• Both LCROSS and LRO shared space aboard an Atlas V launch vehicle.

• Launch occurred at Cape Canaveral.

• Both LCROSS and LRO shared space aboard an Atlas V launch vehicle.

• Launch occurred at Cape Canaveral.

• We used the Atlas V Launch Vehicle.• This is the latest version in the Atlas

family of boosters.• Earlier versions of Atlas boosters

were used for manned Mercury missions 1962-63.

• Atlas V has become a mainstay of U.S. satellite launches.

• NASA has used Atlas V to launch MRO to Mars in 2004 and New Horizons to Pluto and the Kuiper Belt in 2006.

• We used the Atlas V Launch Vehicle.• This is the latest version in the Atlas

family of boosters.• Earlier versions of Atlas boosters

were used for manned Mercury missions 1962-63.

• Atlas V has become a mainstay of U.S. satellite launches.

• NASA has used Atlas V to launch MRO to Mars in 2004 and New Horizons to Pluto and the Kuiper Belt in 2006.

Launch Vehicle

• Launch was from Space Launch Complex 41 (SLC-41) at Cape Canaveral.

• Historic site where many previous missions launched:

• Helios probes to the Sun• Viking probes to Mars• Voyager planetary flyby and

deep space probes• Mars Reconnaissance

Orbiter• New Horizons spacecraft to

Pluto and Kuiper Belt

• Launch was from Space Launch Complex 41 (SLC-41) at Cape Canaveral.

• Historic site where many previous missions launched:

• Helios probes to the Sun• Viking probes to Mars• Voyager planetary flyby and

deep space probes• Mars Reconnaissance

Orbiter• New Horizons spacecraft to

Pluto and Kuiper Belt

Launch Site

When?When?

• LRO/LCROSS launched June 18, 2009.

• This led to impact at 11:30UT on October 9 for LCROSS.

• Impact targeted the South Pole region of the Moon.

• LRO/LCROSS launched June 18, 2009.

• This led to impact at 11:30UT on October 9 for LCROSS.

• Impact targeted the South Pole region of the Moon.

Centaur-LCROSS-LRO at TLICentaur-LCROSS-LRO at TLI

LRO SeparationLRO Separation

LCROSS Lunar Flyby: L + 5 daysLCROSS Lunar Flyby: L + 5 days

Lunar Flyby: June 23, 2009Lunar Flyby: June 23, 2009

LCROSS Trajectory: The Long and Winding Road

LCROSS Trajectory: The Long and Winding Road

• Flyby transitioned to Lunar Gravity Assist Lunar Return Orbits (LGALRO).

• 3 LGALRO orbits about Earth (~36 day period).

• Long transit also provided time to vent any remaining fuel from Centaur.

• Flyby transitioned to Lunar Gravity Assist Lunar Return Orbits (LGALRO).

• 3 LGALRO orbits about Earth (~36 day period).

• Long transit also provided time to vent any remaining fuel from Centaur.

LCROSS taken through Liverpool 2-meter Telescope, La Palma, Canary Islands – Robert Smith

LCROSS in flight taken through an amateur 16-inch telescope – Paul Mortfield

LCROSS in flight taken through an amateur 16-inch telescope – Paul Mortfield

LCROSS Separation: Impact - 9 hrs 40 minLCROSS Separation: Impact - 9 hrs 40 min

Centaur ImpactCentaur Impact

Centaur ImpactCentaur Impact

Into the PlumeInto the Plume

• During the next 4 minutes, the Shepherding Spacecraft descended into the debris plume, measured its composition, and transmitted this information back to Earth.

• The Shepherding Spacecraft then ended its mission with a second impact on the Moon.

• During the next 4 minutes, the Shepherding Spacecraft descended into the debris plume, measured its composition, and transmitted this information back to Earth.

• The Shepherding Spacecraft then ended its mission with a second impact on the Moon.

Cabeus as Seen From LCROSSCabeus as Seen From LCROSS

Centaur Impact From LCROSSCentaur Impact From LCROSS

Centaur Impact PlumeCentaur Impact PlumeLCROSS Visible Camera Image of Ejecta Cloud

10 kmLCROSS / NASA ARC / A. Colaprete

Centaur Impact PlumeCentaur Impact PlumeLCROSS Visible Camera Image of Ejecta Cloud

10 km

Field of View of instruments making measurements of the vapor and debris composition

LCROSS / NASA ARC / A. Colaprete

Centaur Impact CraterCentaur Impact CraterLCROSS NIR Camera image from about 10 km above surface

Centaur Crater

LCROSS / NASA ARC / A. Colaprete

Centaur Impact CraterCentaur Impact CraterLCROSS NIR Camera image from about 10 km above surface

80 meters

LCROSS / NASA ARC / A. Colaprete

LCROSSLCROSSLCROSS Instruments Involved in Water Measurements

UV/Vis Spectrometer

NIR Spectrometer

Water Signatures Detected!Water Signatures Detected!LCROSS Observations with Model Fit

LCROSS / NASA ARC / A. Colaprete

0.95

1

1.05

1.1

1.15

1.2

1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2

Brig

htne

ss

Wavelength (microns)

OH Also Detected! OH Also Detected!

OH Emission

0.5

1.0

1.5

2.0

2.5

3.0

300 305 310 315 320

Ratio

of P

ost-

to P

re-Im

pact

Wavelength (nm)

Band Strength Time aft

er Impact

LCROSS / NASA ARC / A. Colaprete

So How Much Water?So How Much Water?

•At least 100kg or about 25 gallons seen in spectra of impact•First estimates for total in permanently-shadowed areas are about 1-2% of the volume of the Great Salt Lake•50-100 billion gallons!•Amount will be refined by measurements from LRO.

New Questions to AnswerNew Questions to Answer

•Where did the water come from?

•How long has it been there?

•What kinds of processes have been involved in putting it there, modifying it, and removing it?

QuestionsQuestions