I guess if I had answered "billions and billions" of on-topic questions
on the reflector of a lot of years, I would probably not sweat the
question of strict-topic-conformance very much either. Plus the question
is interesting but that's just me.
73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com
On 21-Jan-19 12:47 PM, Steve Lott wrote:
How is this relevant to the Email Reflector
Tower Talk. ????
Steve
KG5VK
On Mon, Jan 21, 2019 at 12:45 PM jimlux <jimlux@earthlink.net> wrote:
On 1/21/19 9:57 AM, k7lxc--- via TowerTalk wrote:
Howdy, TowerTalkians --
The recent Chinese moon landing on the dark side has me wondering
how they communicate from back there. Since we're talking line of sight
frequencies with no atmospheric scattering or repeater relay capabilities,
what's going on? Inquiring minds want to know. Tnx!
Relay satellite in a halo orbit at L2. L2 is on the far side of the
Moon, about 450 million km from Earth (the Moon is around 385 million km
from Earth)
https://en.wikipedia.org/wiki/Halo_orbit
Although we talk about it as a round circular orbit in a plane, in
reality the orbit is more like the edge of a Pringles potato chip. It's
not planar. There's a whole family of stable orbits that look like 3D
lissajous figures.
For what it's worth, there's also Moon libration, and some tall
mountains near the Lunar south pole.. if you land there, you're
technically on the far side, but the mountain is high enough to see over
the edge, helped a bit by diffraction. There's also schemes to use
diffraction from within Aitken Basin for comm without a relay (perhaps
in an emergency, if your relay satellite dies)
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|