by Astrogator Mike | Oct 9, 2013 | General Comments
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:
And we are here in the orbit:
If you could see the orbit from Earth you’d see this:
by Astrogator Mike | Oct 9, 2013 | General Comments
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:
And the orbit from above would look like this:
From Earth, if you could see the orbit, you’d see this:
Go LADEE!
by Astrogator Mike | Oct 8, 2013 | General Comments
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:
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.]
And finally the really cool view AstrogatorJohn came up with yesterday of the view of the orbit from the Earth:
So if you go outside tonight and see the Moon, imagine this orbit.
by Astrogator John | Oct 8, 2013 | General Comments
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.
by Astrogator John | Oct 7, 2013 | General Comments
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
