LCROSS, LRO and Centaur, during Trans-Lunar Injection, 46 minutes after launch.

Launch deliveries are never perfectly accurate – there are always “delivery errors” that a spacecraft has to make up for to get on track after launch. Our mission is no different. On this day, we’ll plan for our first Trajectory Correction Maneuver, or TCM, which happens 25 hours after we started our outbound journey toward the moon. One shift spends most of its time planning TCM 1 (while monitoring the spacecraft), the second shift “executes” the maneuver, then evaluates how well we did, based upon tracking data from the DSN. This is a mission-critical maneuver, and must be performed well.

Right after TCM 1, we’ll also perform our first science payload test, called Quicklook. It’s a simple test: power on the payload and instruments, and perform sampling on each one to verify that everything is functional. Then power everything off.

Day 3: TCM 2 Planning and Execution:

This day is a lot like Day 2, except the second TCM, 24 hours after TCM 1, should be smaller than the first. In fact, if TCM 1 goes perfectly, and nothing else disturbs our orbit (unlikely), we can skip TCM 2. We’ll continue evaluating spacecraft health, and getting the feel for how it operates for real.

Day 4/5: TCM 3 Planning and Execution, and Star Field Calibration:

TCM 3 is a “clean-up” maneuver for TCM 2, and should be even smaller than TCM 2. More importantly, we’ll be performing another science payload activity, called Star Field Calibration, just a few hours after our third “burn”.

The goal of Star Field Cal is to measure the alignment angles between the science camera “boresight”, or camera field-of-view centerline, and the “star tracker”, the instrument that tells our spacecraft what direction it is facing. One can measure this on the ground before launch, but there is some worry that the jostling that occurs at launch might cause the science instruments to move. Once we know the actual alignment between those two instruments, we can point the spacecraft in the right direction to direct the cameras at interesting targets on the moon. To find out, the Star Field Cal event will point our cameras at a known field of stars that we can recognize, and will simultaneously record data from the star tracker. Performing a special sequence of attitude changes, we will be able to derive the alignment offset between the two.