3 ms·

The lander plans to transmit data to Earth using a relay satellite orbiting at the Earth-Moon L2 halo orbit: http://www.planetary.org/blogs/guest-blogs/2018/051

The lander plans to transmit data to Earth using a relay satellite orbiting at the Earth-Moon L2 halo orbit: http://www.planetary.org/blogs/guest-blogs/2018/0519-change-4-relay-satellite.html http://www.planetary.org/blogs/guest-blogs/2018/0519-change-... The relay satellite included two micro-satellites for the moon, only one of them survived: http://www.planetary.org/blogs/guest-blogs/2018/20180615-queqiao-orbit-explainer.html http://www.planetary.org/blogs/guest-blogs/2018/20180615-que...

Isamu 8y ago
That Earth-Moon L2 halo orbit is cool, I didn't even know that was a thing. [edit] I mean I was aware of Lagrange points, but not the practicality of the halo orbit. This is a nice explanation: http://hyperphysics.phy-astr.gsu.edu/hbase/Mechanics/lagpt.html http://hyperphysics.phy-astr.gsu.edu/hbase/Mechanics/lagpt.h...
- Florin_Andrei 8y ago
  Yeah, it instantly makes sense if you calculate the force at the Lagrange point and notice the vector points back at the exact L point when you're in the vicinity - and then you go, hmmm, looks like it might be possible to orbit that thing.
- acranox 8y ago
  https://en.wikipedia.org/wiki/Lagrangian_point https://en.wikipedia.org/wiki/Lagrangian_point
  - Isamu 8y ago
    An interesting point from that page: >A full n-body dynamical system such as the Solar System does not contain these periodic orbits, but does contain quasi-periodic (i.e. bounded but not precisely repeating) orbits following Lissajous-curve trajectories. These quasi-periodic Lissajous orbits are what most of Lagrangian-point space missions have used until now. Although they are not perfectly stable, a modest effort of station keeping keeps a spacecraft in a desired Lissajous orbit for a long time.
  - daveslash 8y ago
    https://en.wikipedia.org/wiki/Halo_orbit https://en.wikipedia.org/wiki/Halo_orbit "Halo orbits can be thought of as resulting from an interaction between the gravitational pull of the two planetary bodies and the Coriolis and centrifugal accelerations on a spacecraft."
- enos 8y ago
  Will L2 congestion become a problem once JWST and a few more missions join this craft? Will we have to manage that orbit like we do with geostationary?

Isamu 8y ago

That Earth-Moon L2 halo orbit is cool, I didn't even know that was a thing. [edit] I mean I was aware of Lagrange points, but not the practicality of the halo orbit. This is a nice explanation: http://hyperphysics.phy-astr.gsu.edu/hbase/Mechanics/lagpt.html http://hyperphysics.phy-astr.gsu.edu/hbase/Mechanics/lagpt.h...

Florin_Andrei 8y ago
Yeah, it instantly makes sense if you calculate the force at the Lagrange point and notice the vector points back at the exact L point when you're in the vicinity - and then you go, hmmm, looks like it might be possible to orbit that thing.
acranox 8y ago
https://en.wikipedia.org/wiki/Lagrangian_point https://en.wikipedia.org/wiki/Lagrangian_point
- Isamu 8y ago
  An interesting point from that page: >A full n-body dynamical system such as the Solar System does not contain these periodic orbits, but does contain quasi-periodic (i.e. bounded but not precisely repeating) orbits following Lissajous-curve trajectories. These quasi-periodic Lissajous orbits are what most of Lagrangian-point space missions have used until now. Although they are not perfectly stable, a modest effort of station keeping keeps a spacecraft in a desired Lissajous orbit for a long time.
- daveslash 8y ago
  https://en.wikipedia.org/wiki/Halo_orbit https://en.wikipedia.org/wiki/Halo_orbit "Halo orbits can be thought of as resulting from an interaction between the gravitational pull of the two planetary bodies and the Coriolis and centrifugal accelerations on a spacecraft."
enos 8y ago
Will L2 congestion become a problem once JWST and a few more missions join this craft? Will we have to manage that orbit like we do with geostationary?