General Question Radio Comms Moon Base/ Sat/Earth

[paddy2]

Working on a model of a radio dome (Radome) and got to thinking about how a full time base on the moon would maintain contact with earth?

With a 28 day "day" to worry about, a given base would be out of sight for 14 days. ( Albeit a simple standpoint.)

So do we have a number of relay stations around the Moon, as earth did for Apollo? Do we have a number of low moon orbit birds to pass the message on. Do we just not talk to the folks back home the last week in July?

So here's the 1st question, Can Brighton Beach Talk to earth 24/7?
if yes how???

2nd question, Given none 24/7 comms, what would be acceptable/cost effective and what would be unacceptable/ too risky?

hmm::shrug:As some times it is not so easy to convey feelings, this is written as a light hearted querry NOT as a flame war)

 

[boogabooga]

I'm confused. Brighton Beach ALWAYS faces earth. (Tidal lock)

 

[paddy2]

I can not believe I did not think this through!!!
Because its not iluminated does not mean its moved out of "sight"
Sorry folks I feel a right %$&*"

 

[Donamy]

:facepalm:

 

[paddy2]

:facepalm: true so very true

 

[statickid]

I have wondered about the placement of a lunar base. Would a polar base be the best so as always be in the terminator? Is it even possible to have perpetual sunlight at one location or does some kind of tilt make it impossible?

 

[PhantomCruiser]

I read somewhere (on this board I think even) about a crater on the moon (at the pole) that is a "point of eternal light" or something, the rim of the crater gets continual sunlight unless the moon is in the Earth's shadow.

 

[sorindafabico]

I have wondered about the placement of a lunar base. Would a polar base be the best so as always be in the terminator? Is it even possible to have perpetual sunlight at one location or does some kind of tilt make it impossible?

[ame="http://en.wikipedia.org/wiki/Peak_of_eternal_light"]Peak of eternal light - Wikipedia, the free encyclopedia[/ame]

 

[garyw]

I have wondered about the placement of a lunar base. Would a polar base be the best so as always be in the terminator? Is it even possible to have perpetual sunlight at one location or does some kind of tilt make it impossible?

The poles would be good, there is water ice in the shadow plus you have perpetual sunlight.

Other locations on the moon would be fine if there is water ice that can be taped, there is a lot that can be done with water ice from fuel to oxygen to drinking water.

The big problem with any lunar base would be the lunar dust storms stirred up by a rising sun -> http://science.nasa.gov/science-news/science-at-nasa/2005/07dec_moonstorms/

So do we have a number of relay stations around the Moon, as earth did for Apollo? Do we have a number of low moon orbit birds to pass the message on. Do we just not talk to the folks back home the last week in July?

I've been thinking about this myself. If you've got a lunar base then you'll want to do 'over the hill' expeditions so how would they keep in contact with the base? there isn't an ionosphere to bounce radio signals off so I'm thinking either radio relay points or orbiting comms satellites. Lunar GeoSync isn't an option so any system would need to know where the satellites are to bounce through them.

 

[Cosmic Penguin]

The poles would be good, there is water ice in the shadow plus you have perpetual sunlight.

Other locations on the moon would be fine if there is water ice that can be taped, there is a lot that can be done with water ice from fuel to oxygen to drinking water.

The big problem with any lunar base would be the lunar dust storms stirred up by a rising sun -> http://science.nasa.gov/science-news/science-at-nasa/2005/07dec_moonstorms/



I've been thinking about this myself. If you've got a lunar base then you'll want to do 'over the hill' expeditions so how would they keep in contact with the base? there isn't an ionosphere to bounce radio signals off so I'm thinking either radio relay points or orbiting comms satellites. Lunar GeoSync isn't an option so any system would need to know where the satellites are to bounce through them.

Can the Earth-Moon Lagrange points work as the base for lunar communication spacecrafts?

 

[garyw]

Can the Earth-Moon Lagrange points work as the base for lunar communication spacecrafts?

I don't see why not but I was thinking more along the lines of 4 spacecraft at 90 degress apart in orbit at 800km or so. At a high altitude you've got more coverage, better line of sight to other satellites and, hopefully, less orbit changes due to Mascons.

Edit to add:

I've done a few quick and dirty calculations here based on a mission I've been working on for my VSA which is a trip from Brighton Beach to the Apollo 15 landing site at Hadley Rile which is 1,000km away.

Assuming that the Prelude base is 50m high that means that any trip to Hadley is out of comms range at just 32km! To provide radio relays all the way to hadley would require about 31 of them. Satellites are the way to go.

Obviously, this ignores hills and things which would provide for either a better vantage point or signal blocking. :lol:

 

[statickid]

I think that for near base operations, a repeater tower on the biggest nearby mountain would be reliable for folks on the ground. It might make managing radio traffic easier too, with plenty of spectrum for lots of chatter. Communication between bases, like you say, should definitely be handled by satellites.

 

[Capt_hensley]

I think that for near base operations, a repeater tower on the biggest nearby mountain would be reliable for folks on the ground. It might make managing radio traffic easier too, with plenty of spectrum for lots of chatter. Communication between bases, like you say, should definitely be handled by satellites.

Burried Cable, Like Fiber Optics, for surface base to base, It means jobs, planning, and product consumption. FO requires low voltage low current media converters, and these can be solar powered rechargable stations.

It's not unherd of, look at all the cabe AT&T put on the ocean floors durring the 70's.

 

[N_Molson]

You could easily put a base on the dark side, in fact there are some buried NASA plans for that and the idea of a SETI-like installation shielded from our radio interferences by the Moon. Communications with Earth can easily be achieved using satellite relays, it's something we use everyday without even noticing it.

And BTW the "dark side" receives exactly the same amount of sunlight than the other

 

[PhantomCruiser]

"There is no Dark Side of the Moon really, matter of fact it's all dark"

 

[statickid]

Burried Cable, Like Fiber Optics, for surface base to base, It means jobs, planning, and product consumption. FO requires low voltage low current media converters, and these can be solar powered rechargable stations.

It's not unherd of, look at all the cabe AT&T put on the ocean floors durring the 70's.

yes, look at the undersea cables... for me, this is evidence that burying 1000 kms of cable is NOT a viable option, especially when simple launching a few satellites will do the job better. I say better because multiple bases all over could use the same satellites. The primary reason for laying undersea cables is for the sheer bulk of information being sent. Not even touching the subject of digging trenches on the moon.

P.S. ocean cable is not out dated technology, AFAIK its still the primary transmission of information (read: internet) across oceans right now.

 

[Hlynkacg]

Can the Earth-Moon Lagrange points work as the base for lunar communication spacecrafts?

Yes, in fact the Apollo Apllications project missions included the addition of a deployable antenna to the SIVb stage so that it could function as a communications relay for the CSM and proposed Lunar Orbital station when they were on the far side of the moon.

ETA:
The orginal study I read was on NTRS and thus no longer available but here is one that appears to be related.

http://www.nasaspaceflight.com/_docs/haloOrbitLunarStation.pdf

 

[Capt_hensley]

yes, look at the undersea cables... for me, this is evidence that burying 1000 kms of cable is NOT a viable option, especially when simple launching a few satellites will do the job better. I say better because multiple bases all over could use the same satellites. The primary reason for laying undersea cables is for the sheer bulk of information being sent. Not even touching the subject of digging trenches on the moon.

P.S. ocean cable is not out dated technology, AFAIK its still the primary transmission of information (read: internet) across oceans right now.

FO Cable is very light, but the armor is the contributing factor to excessive weight. I don't think digging trenches on the moons surface would be that difficult.

I could present arguments but that would be futile, However I thinking the cost would be in the ball park. It's just a matter of how you want the job done. Both methods have merit, most satellites can handle far more data these days. I was just bouncing an alternative around!. Cool image of the layer vessel.

 

[garyw]

FO Cable is very light, but the armor is the contributing factor to excessive weight. I don't think digging trenches on the moons surface would be that difficult.

You might not even need a trench, just let the cable covers sit in the regolith.

Could the lunar dust cause any sort of the problem with the cables or the cable protectors though? It's highly magnetic and gets into everything.

 

[Capt_hensley]

You might not even need a trench, just let the cable covers sit in the regolith.

Could the lunar dust cause any sort of the problem with the cables or the cable protectors though? It's highly magnetic and gets into everything.

To my knowledge about FO cable, the armor that's used as "Plenum" type for indoor use would be sufficient for a burial of 3-6" of dust. The moons average dust depth is about that. Mountains and boulders might be a challenge but diamond bits work really well. Since there is only "impact erosion" without any water or wind problems, the chance the cable would chafe, is very slim to none.

You burry it on the moon for only two reasons, Temperature, and Impact damage from small local impacts. A large impact would present a repair opportunity. Could you imagine being a FO cable splicer on the surface of the moon, sitting in your van/rover?

Magnetic dust will not affect the light transmission, it's simply far too week. It would take something on the order of a cyclotron to make a significant db loss. They use FO cable in the Cern LHC for ultra high speed, and moderate data transfer from the detectors. It's also a high temperature environment, but polymers are used now, not glass, but a glass hybrid. It's more flexible and tolerant to temp changes.