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TECHNICAL
INFO |
Lunar
CRater Observation and Sensing Satellite (LCROSS) |
Impactor Targeting
Figure 1 |
Figures 1 and 2 depict the trajectory that will be used to target the
LCROSS Centaur upper stage and Shepherding Spacecraft into a North or
South Pole crater. The 86-day (5 day earth-lunar transit plus 81 day earth
orbit) Lunar Gravity-Assist, Lunar Return Orbit (LGALRO) was chosen to
allow LRO time to complete its two-month commissioning phase and conduct
nearly a month of science data collection of polar crater measurements.
The LGALRO orbit can be
Figure 2 |
established for any LRO launch opportunity and the Centaur impact can be
timed to allow LRO and key ground observatories to observe the ejecta
plume generated by a high-velocity and steep incident angle impact (Figure
3). Dual viewing of the Centaur impact by the LCROSS Shepherding Spacecraft
and LRO can provide additional perspective and redundant data collection.
The initial science scenario and Shepherding Spacecraft propellant sizing
inputs assume that the Shepherding Spacecraft separates from the Centaur
9 hours before impact and that a 50 m/s braking maneuver will slow the
Shepherding Spacecraft 10 minutes behind the Centaur. This allows 4 minutes
of instrument observations and real-time transmission before the Shepherding
Spacecraft itself impacts the same permanently shadowed crater, or if
desired, one adjacent to it.
Figure 3 |
Technical Information
Overview | Mission
Rationale | Spacecraft and System Description
| Instrumentation | Water
Detection | Targeting
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Visit the NASA Mission Site @ http://www.nasa.gov/lcross
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