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Where is LADEE Now, and where is it going?

After the successful launch of LADEE last Friday:

NASA’s LADEE Page

you may be wondering where the LADEE spacecraft is now, and what are the next steps on the trajectory. So here we are, LADEE on Sept 11, 9 AM PDT:

LADEE on Sept 11, 2013

LADEE on Sept 11, 2013

Note the upcoming phasing loops (dotted) and the Moon to the upper right. Of course this is a 3-D picture, and you can get a better feel for where the Moon is now here:

LADEE on Sept. 11, 2013 with Moon (side view)

LADEE on Sept. 11, 2013 with Moon (side view)

We (LADEE Flight dynamics) often like to look at the lunar trajectories in an Earth-Moon rotating frame. The Earth is at the middle, the Moon at the top:

LADEE on Sept. 11 (Earth-Moon Rotating Coordinate frame)

LADEE on Sept. 11 (Earth-Moon Rotating Coordinate frame)

On Sep. 13, 2013, LADEE will reach first perigee:

LADEE at first perigee

LADEE at first perigee

The first orbit-raising maneuver (after the test maneuver on Sep. 11) will occur here. This maneuver is called Perigee Maneuver 1 (PM1) and will raise LADEE’s orbit and change the orbit period from 6.44 days to 7.6 days. This brings us to perigee 2 on Sep. 21, 2013:

Perigee 2

Perigee 2

From here we perform PM2, and raise the orbit period to 10 days. We get back to perigee 3 on Oct. 1, 2013:

Perigee 3

Perigee 3

We have no nominal burn at Perigee 3 (although we may perform a trajectory correction maneuver there, and one more 36 hrs later for our final precise targeting to our Lunar arrival conditions).

Finally, we take a 5-day transfer to the Moon, where we arrive on Oct. 6, 2013 for our first Lunar Orbit Insertion burn (LOI-1). We use 3 maneuvers for Lunar capture, which we will describe in another post.

Lunar Approach

Lunar Approach

Here’s a few more pictures of the complete LADEE trajectory:

Complete LADEE Cislunar Trajectory, Earth Centered Inertial coordinate frame.

Complete LADEE Trajectory, Earth Centered Inertial coordinate frame.

Complete LADEE Cislunar Transfer trajectory, Earth-Moon Rotating Coordinate Frame

Complete Lunar Transfer trajectory, Earth-Moon Rotating Coordinate Frame

  • Jonathan McDowell

    Nice! I’ve been following on JPL Horizons since I can get the actual numbers there… unless there is a better source? Let us know how the test burn goes

  • http://www.astrogatorsguild.com/ Astrogator_mike

    Horizons has the real stuff, their ephemeris is coming directly from the DSN portal, which we upload to regularly in order to keep the Antennas pointed properly.

  • http://www.astrogatorsguild.com/ Astrogator_mike

    Test burn at 23:00 UTC. Everything currently on schedule.

  • Jonathan McDowell

    Thanks – and thanks for posting the time of the test burn, I look forward to your updates. Go LADEE!

  • Jonathan McDowell

    I think the segment in Horizons called “20130916_092827_to_20131018_161740_SEP162013 ” which covers 2013-Sep-21 from 11:02 to 15:02 UTC is screwed up – it shows a drop of apogee back down to 271800 km for that period. Presumably just a patch that wasn’t covered by other updates and will be updated post the PM-2 burn (for which, good luck!)

  • http://www.astrogatorsguild.com/ Astrogator_mike

    There was an issue with the Horizons ephem that has now been fixed. Horizons currently has an ephem that extends from right after launch, all the way through the science orbit. It should be relatively accurate. Previously, Horizons had been getting their spice files from the DSN portal, which is where we upload ephemeris data to allow the DSN stations to track LADEE. Unfortunately, the DSN propagators had issues with ephemeris files that contained maneuvers, so our OD folks cut out sections of the ephemeris files and posted those to the portal. The Horizons folks grabbed these same files, not knowing of the editing that had occurred, and their system used previous (pre-launch) ephems to fill the missing data. That cause the issue you saw. We fixed it though, and created (from our best OD solution) a full ephem from launch to current time, and attached our current predicted ephem through end of mission. It’s a pretty cool ephem actually (I love our team, all of our people really live and breath this stuff!). We’re using that same ephem now in the Flight Dynamics room (and elsewhere) to show the current position of the spacecraft.

  • Jonathan McDowell

    Great – and I see it’s back in Horizons, thanks. These sorts of configuration issues are not surprising between organizations, thanks for sorting it out. Seems like you have a very cool team on a very cool mission, I wish you all the very best (even if we on Chandra are probably going to be fighting you for DSN time :-))