LADEE Trajectory Update 10-9-13: LOI-2 nominal

The LADEE Lunar Orbit Insertion burn 2 (LOI-2) executed as planned this morning at 3:38 PDT, placing LADEE into a 4 hr orbit.  Things move much faster now for the spacecraft, and the Moon is looking a lot bigger. We originally captured with a periselene altitude near 560 km but our periselene has now been lowered to an altitude of ~235 km by Earth perturbations in the Post-LOI-1 24 hr orbit.  The planned periselene of the commissioning orbit was 250 km, however the small (<1%)  underperformance of LOI-1 caused aposelene to be slightly higher, and thus we got slightly more Earth perturbations than we nominally planned for.  The result of this is that we got a bit of free lowering from the Earth, which we’ll take!  (Since we plan to go lower than 250 km anyway).  So the current plan is to drop the aposelene to 250 and perform commissioning there in the 235 x 250 km orbit.

LOI-2 lowered our apogee down to ~2200 (we’ll have to wait for some more tracking to verify that exactly).

From our pre-LOI2 planning, things should now (9 Oct 2013 13:00 UTC)  look like this:

 

ladeeview

 

And we are here in the orbit:

moonview

 

 

If you could see the orbit from Earth you’d see this:

 

earthview

 

LADEE Trajectory Update 10-9-13: 4 hrs to LOI-2

Lunar Orbit Insertion Maneuver 2 (LOI-2) is upon us, scheduled for 09 Oct 2013 10:38 UTC.  This maneuver will lower our periselene altitude from 15700 km down to 2220 km and change our orbit period from 24 hrs to 4 hrs.

The maneuver will last for 220.8 seconds, and will impart a delta-V (change in velocity) of 293 m/sec.

Right now LADEE sees this view:

 

ladee view

 

 

And the orbit from above would look like this:

 

topview

 

 

From Earth, if you could see the orbit, you’d see this:

 

earth view

 

 

Go LADEE!

LADEE Trajectory Update: 10-08-13

LADEE is now in its last rev in the 24 hour capture orbit, and preparing for LOI-2, which will lower the spacecraft into a 4 hr orbit.  LOI-2 is scheduled for 10:38 UTC (3:38 AM PDT) Wed. morning, Oct. 9. Here’s the view from LADEE to the Moon:

 

moonandsun

 

Here’s the orbit [Note: blue shows the 4 hr orbit we’re going to next.  Dotted lines show the past trajectory, solid are into the future.  So we’re not quite at aposelene yet.]

 

lunar orbit

 

And finally the really cool view AstrogatorJohn came up with yesterday of the view of the orbit from the Earth:

 

moonfromearth

 

So if you go outside tonight and see the Moon, imagine this orbit.

LADEE’s Orbit as seen from Earth

After posting the picture of the Moon from the parking lot at Ames, we thought it would be cool to see what LADEE’s orbit would look like, if we could see it, from the Earth.  The picture below is from the Earth to the Moon, with Ecliptic North at the top.  The White Orbit is our current orbit, and the small white circle is where LADEE was when I took this snap… it’s moving to the right, towards periselene; the Blue Orbit is what it will be after LOI-2, and the Green Orbit is the near circular orbit we will stay in during commissioning for about a month before we start science operations.

LADEE's orbit as seen from Earth

Planning LOI2 – and taking a break to look for LADEE

Astrogator Mike is in the Flight Dynamics Room planning our second lunar maneuver, Lunar Orbit Insertion-2 (LOI2), and I (Astrogator John) am processing tracking data doing orbit determination.  Mike noticed the Moon and Venus over the parking lot, so I went out there with him took this picture with my phone.  That’s Venus to the left of the Moon.

LADEE is orbiting around that Moon

LADEE is orbiting around that Moon

 

LADEE Update 10-07-13: Safe in Lunar Orbit after LOI-1

The LADEE Spacecraft successfully performed Lunar Orbit Insertion maneuver 1 (LOI-1) on Oct. 6, 2013 3:57 PDT.   The LOI-1 maneuver captured LADEE into a 24 hr orbit.  After 3 days (and 3 revs) in the capture orbit, the spacecraft will perform LOI-2 on Oct. 9 at 3:37 PDT.  The second of 3 Lunar Orbit Insertion maneuvers, LOI-2 will reduce LADEE’s orbit down to a 4 hr orbit.

Finally, LOI-3 will be performed Oct. 12 at 8:00 PM PDT to circularize the spacecraft in a 235 km orbit.  LADEE will spend a month in this “commissioning” orbit, while the spacecraft is checked out before full-time lunar science begins, and the Laser-Communications experiment will be tested.

 

Moon View

 

 

At this time (7 Oct. 2013 7:53) LADEE is past its first aposelene, and is headed for its first periselene after capture.

 

 

Moon centered

 

LADEE in Lunar Orbit

The LADEE spacecraft is now in Lunar orbit.  Tracking data will later confirm the precise parameters of the orbit, but based on telemetry of thruster performance and accelerations, the LOI-1 burn appears to be close to nominal.

The planned Lunar orbit has an orbit period of 23.1 hrs.  The next planned maneuver (Lunar Aposelene Maneuver 1, or LAM1) is scheduled for the 2nd aposelene, which would occur roughly 1.5 days from now.  For LOI-1 results close to nominal, this maneuver can be waived.

LOI-2 is nominally scheduled for 3 revs after LOI-1.