Mike’s Tweets

Sep 30 LADEE Trajectory Update

LADEE on 9-30-2013 18:05 UTC (Rotating Coordinate Frame)

LADEE on 9-30-2013 18:56 UTC (Rotating Coordinate Frame)


LADEE on 9-30-2013 18:56 UTC (Earth-Centered Inertial Coordinate Frame)



LADEE on 9-30-2013 18:56 UTC (Top View)



Next Maneuver:  TCM-1 on 1 Oct. 2013 22:00:00 UTC (11 hrs after Perigee 3).

  • Denniswingo


  • Denniswingo

    How much is the Moon pulling the apogee up?

  • Renee Wesley

    Great job guys!!! The LADEE trajectory looks a little familiar to me. : )

  • The Moon doesn’t directly pull up the apogee, but rather adds (or subtracts) velocity when we’re at apogee. We use this purposefully to plan our launch window and the trajectory. The Moon raises our perigee both on our first revolution and our 3rd. On the first apogee, we timed the launch window so that the Moon would add velocity at apogee and serve the same function as a maneuver at that spot would serve. The Minotaur launched us onto an orbit with a 200 km perigee altitude. After we came around once, our next perigee was at about 2300 km (altitude). On our second apogee, the Moon lowers us a bit (down to about 1500 km altitude) and then on the third apogee, the perigee altitude is brought back up to about 1650 km. On the final approach, it’s interesting to think about what the apogee is doing right before we get to the Moon. We’ve plotted out Apogee altitude vs time, and Lunar Altitude vs time. Apogee Altitude is a 2-body quantity, and obviously becomes less meaningful as we get closer to the Moon. Once we get into orbit at the Moon, it’s not even well defined. Still though you can see that even within 5000 km, the orbit still has a reasonable Apogee altitude.

  • Looks a lot like IBEX doesn’t it? We’re getting closer now though, to something IBEX never quite did 🙂 Wait until Sunday!

  • Renee Wesley

    I will stay posted for Sunday!!!