Principle Investigator Payload Manager

1. Anthony Colaprete Principle Investigator Payload Manager

2. Target Selection Criteria • The four primary criteria for selection: • Terrestrial Observations (to insure minimum success requirements). • Illumination of ejecta by sunlight • Target properties (e.g., surface roughness, slopes, and regolith depth) • Observed concentration of increased hydrogen

3. Terrestrial Viewing Constraints • Observatory Viewing Constraints: • Observatory needs to be 2hrs from dawn/dusk at impact • Impact must occur when moon is more than 30 deg away from new moon or full moon • Elevation angle of moon at impact relative to observatory must be greater than 45 deg • Maximum impact time adjustment of 12hrs allowed (due to DV limitations)

4. Altitude Mask Ejecta Illumination Ejecta Illumination dominates sensitivity analysis. Predicted NIR Spec Water Ice Sensitivity Shackleton Shoemaker To Earth

5. Optimum Target vs Launch Date The optimum site varies with launch date due to changes in solar illumination angle and impact angle (from ARC-04.01.SciImpSite.01.v-3.0): The LCROSS Science Team recommends a target be selected for each possible LRO launch date and if possible all targets be limited to the South Pole. Furthermore, the LCROSS Science Team recommends new data be used to refine targeting up until 30 days prior to Centaur separation.

6. Target Selection Process Selection Process: Craters A, B, C, or D Terrestrial Observations Project Requirements (e.g., dV) Craters A, B or D SC Water Sensitivity, RFA PL-CDA-02 Hydrogen Ejecta Illumination Crater Selection Craters A or B Crater B Surface Properties New Data

7. Target Selection Process

8. Selected Targets • Target Selection Products • Impact Site Selection Workshop, October 2006 • Impact Site Report from the Site Selection Committee: Impact Site Selection Committee Report (ISSCR) (November, 2006) • LCROSS Science Team Impact site Position Report (STIPR) (January, 2007) • Baseline Target Review (July, 2007) Campbell et al., 2007

9. Selected Targets Sh Fa

10. Baseline 2008 Impact Sites * Faustini as selected when sensitivity margins in Shoemaker were low, and was selected over Shackleton due to its high sensitivity margins and knowledge of target properties. † Cabeaus was selected when all other target sensitivity margins where marginal or poor relative to the requirement or Cabeaus. A: Visibility to Earth B: Good sensitivity margin C: Knowledge of target properties

11. Baseline 2008 Impact Sites * Faustini as selected when sensitivity margins in Shoemaker were low, and was selected over Shackleton due to its high sensitivity margins and knowledge of target properties. † Cabeaus was selected when all other target sensitivity margins where marginal or poor relative to the requirement or Cabeaus. A: Visibility to Earth B: Good sensitivity margin C: Knowledge of target properties

12. Target Refinement LCROSS retains the ability to change our target with the southern polar region (with about ~100 km of our original target): Target refinement within current targeted craters based on on-going analysis of existing data and analysis of new data (table below) Target refinement can occur as late as 30 days prior to impact date (e.g., for a 3 month cruise, approximately 60 days after launch).

13. Target Selection Backup Slides

14. WEH, ISRU and the Sensitivity Requirement • The most recent water equivalent hydrogen (WEH) retrievals deconvolve the low resolution data set with models of the permanently shadowed regions (Elphic et al., 2007). • The only estimates of WEH for individual craters • Depends on the DEM to create shadowed regions • Pervious estimates broadly (unconvolved) place WEH ~1% • Several theoretical treatments place WEH ~1-2 % • Radar returns associated with water ice requires volumetric scattering that places WEH limits > 20% Water content > 1-2% wt would constitute a more cost efficient than mining “dry” equatorial regolith • For In-Situ Resource Utilization (ISRU), water concentrations of >1% make polar mining more efficient than equatorial mining. • This sets the required sensitivity of detection threshold of 0.5% (RFA PL-CDA-02).

15. Percent Water Sensitivity • The sensitivity of the LCROSS SC nadir viewing NIR spectrometer was used as a verification of the Projects ability to sense regolith water. • The Project must be sensitive to water concentrations of 0.5% wt (RFA PL-CDA-02). • The NADIR NIR Spectrometer is the most sensitive instrument to ejecta cloud water ice, the expected dominant form of water initially within the ejecta cloud. • The performance of the instrument was estimated using a discrete ordinate scattering algorithm (DISORT) and linear mixing of optical constants for water ice and dust. • Water ice and dust opacities were estimated using impact model predictions. • Instrument sensitivity was calculated using expected throughput and noise equivalent power (recent system level calibrations confirm this performance). • For each impact date, several factors, which dominate measurement sensitivities to water ice, are taken into account in the model: • Impact Angle • Solar Illumination Angle • Crater Wall Height • Synthetic spectra for the first 30 seconds following impact are used to determine sensitivity for various concentrations of water ice in the regolith (see backup slides). While a complete error analysis has not been done, it is believed that these estimates are uncertain to approximately ±0.1 %

16. D~5 m (t~1 Myrs km-2) 0.5 1.0 1.5 2.0 Depth (m) D~10 m (t~15 Myrs km-2) Horizontal Distance Crater Lunar Polar Hydrogen Gardened Layer (1Byr) • Space weathering homogenizes [H] at a rate of ~1.5 m per Gyr (Crider & Vondrak, 2003). • Below ~2 m compaction greatly reduces pore space and reduces diffusive [H] capacity, however, burial is still possible. • Impacts which excavate to ~1.5 m deep and have diameters of ~10 m occur on timescales of t~15 Myrs/km2, or about sixty 10 m craters km-2 on a surface 1 Gyrs old. • This crater density results in a mean distance between 10 meter diameter craters of ~150 meters (or 450 meters for 100 Myo surface). • Thus, H2O likely to be horizontally heterogeneous on scales of ~100m to depths of ~1.5 m. Desiccated Layer 0 1 2 3 4 5 Depth (m) Crater burial of “dry” material Crider & Vondrak, 2003 Feldman et al., 2001 10-6 10-5 10-4 10-3 10-2 [H] (wt. parts)

17. Lunar Polar Hydrogen • If heterogeneity is controlled by 10 meter craters (crater excavation controlled), which are out of equilibrium with diffusive and space weathering processes, then the aerial fraction that is in equilibrium, i.e., “wet” is ~1.-102/1002 = 99%. • LP sensed the top meter (~70 cm) Derived LP values representative of this excavation controlled regolith “horizon”: high concentration pockets (WEH greater than few %) in the top meter not likely. • Diffusive and space weathering processes likely to enforce their own horizontal modulation due to environmental effects (e.g., temperature and porosity) 1 km For a 100 Myr Old Surface: • D (m) N • 40 • 5 • 1 • 0.1 • 80. 0.01 D~10 meter 1 km

18. Apollo 11 Craters East Crater ~30 meters 1.0 km West Crater ~200 meters 1.2 km