Mike’s Tweets

LADEE trajectory update 10-4-13

LADEE is rapidly approaching the Moon.  Depending on who you talk to, you can consider the spacecraft to be within the “Sphere of Influence” of the Moon somewhere near 66,000 km (on LADEE we switch central bodies on our numerical integrators at 50,000 km, but that’s not a magic number).  So we’re not quite Moon-Centered yet, but that doesn’t stop us from giving you pictures in a Moon centered frame.

As you can see, showing the Earth orbit no longer has great utility:

ladee ECI

 

 

[Note:  Velocity is still Earth-relative] I have to still show my favorite view of the phasing loops, the Earth-Moon rotating coordinate frame, but Earth-bound phasing loops are about to be less relevant.

 

ladee rotating

 

 

But as much as I like the phasing loops, this is the view we really should be thinking about (and I like it so much I just tweeted it!):

 

ladee moon

 

 

And this view gets me very excited:

ladee MCI

 

 

But we still can look back to where we came from:

 

ladee earth

 

 

If you check the dates on the pictures, you can see what order I created them in, as the dates don’t all match and I’m animating in real time.

  • Jonathan McDowell

    Nice! 66000 km is the Hill sphere and 58000 km is the Earth-Moon L1 point, if I recall correctly – I am still struggling with which to choose as the better boundary to live by in general two body problems 🙂 Seems like the L1 boundary is more ‘real’ in practical situations of where a loosely bound object will end up