Feb 18, 2020
S1E9 – Lunar Communications Network
We landed on the moon. We built a habitat on the moon.
We are living in earth orbit, and we are living in lunar orbit.
We are living on the far side of the moon, with no visibility to earth...ever.
With four space stations, two lunar bases, and over 35 crewed trips between the earth and the moon, how can we possibly communicate with each other over the long term?
How can we keep all these missions in communications with earth?
The answer, is a communications network that grows and becomes more sophisticated as time goes on. By the end of the Apollo-era, we can communicate over a half million miles without the requirement that we be line of sight with an earth based antenna. This required a sophisticated network of communications satellites and technologies…and a bit of luck.
This is the Apollo Lunar Communications Network. In the world of Belitopia.Links
* Episode Details (https://belitopia.com/109)
* Belitopia Information from this Episode (https://belitopia.com/lunarnet)
* Lagrangian Points (https://en.wikipedia.org/wiki/Lagrangian_point)
* Lunar Fronzen Orbits (https://en.wikipedia.org/wiki/Frozen_orbit#Lunar_frozen_orbits)
* Precession (https://en.wikipedia.org/wiki/Precession)
* Lunar Wobble - NASA (https://svs.gsfc.nasa.gov/10836)
* Lunar Libration - Wikipedia (https://en.wikipedia.org/wiki/Libration#Lunar_libration)
* Earth Rise - Famous picture from Apollo 8 (https://en.wikipedia.org/wiki/Earthrise)
As we near the end of season one, we’re going to try a slightly new format for this episode. We aren’t going to use the future documentary format, rather we are going to stay in a current day conversation. In this episode, we’re going to be talking about the fledgling communications network being built in the 1960s, 1970s, and 1980s to support the various Apollo missions we have previously discussed in season 1. We’ve talked about part of this network briefly in episode 7, when we talked about the lunar base on the far side of the moon...the BLA base. But there’s a lot more to that network than you imagine, and a lot more to lunar communications in general than you might think. This network was the first such extra-earthly communications network, and it was developed during the early days of the space race.Global Earth Dish Network
During the early Apollo days, during our first missions to the moon, one of the initial communications problems that had to be solved was how do you keep the moon-bound Apollo space craft in communications with earth, when the earth keeps rotating. That means, mission control, in Houston, Texas, was only in line of site of the Apollo space craft for relatively short periods of time every day — a few hours at most.
In order for Houston to maintain a 24 hour a day communications with the moon-bound space craft, a series of satellite communications stations were built around the globe. As the earth rotated, different stations around the globe were in line of sight communications with the Apollo spacecraft at different times during the day. These stations were in direct communications with Houston via landline communications channels...essentially phone calls. Each station, when it was their turn, would relay signals between the Apollo space craft and mission control. The result was a virtual 24...