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Does landing on far side of the Moon is possible?


Pawelk198604
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I just wonder why during Apollo era no one  tried to land on back side of the Moon?

I just wonder, because today landed on opposite side of Minmus on KSP, i did not play KSP for long time and forgot how wonderful and  intellectually enriching playing KSP is :D

to make a long story short, when i played KSP and landed on Minmus i forgot that i put on Minmus a satellite over month ago (lin this case literally and figuratively :wink: ) so i landed on back side of the Minmus and satellite bounced my radio to KSC 

So i wonder, Hey why NASA not tried this IRL :wink: 

The obvious is that NASA could not have a permanent direct connection with LEM, but a relay in orbit around the moon would solve the problem.

I know there are more geek in this forum who know better about orbital mechanics than me, and probably many of you will find this idea stupid, but still I would like to know your opinion?

   

 

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It was easier to land on the near side than to go through the trouble of setting up a relay.

They were pressed for time, too, with the cold war space race and Kennedy's goal of landing there before the end of the decade.

Besides, there's a bunch of really big flat spots on the near side so it's easier anyway.

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7 minutes ago, Pawelk198604 said:

I know that but they can just place relay on Moon orbit.

Correct. But, it costs extra, and if the relay breaks so does contact with the lander and crew. Also potential landing sites could be better mapped on the seen side of the Moon. Finally since none of Moon's surface was explored there was little to gain for that extra expense and risk. Same amount of new knowledge was available on the visible side.

Today; sure, why not? We have a working relay set (maybe not enough to call a network just yet) around Mars; the moon is a cakewalk with that experience. Also we have samples from the visible side; comparisons to the back side could yield new insight even if they just confirmed it's made of the same stuff. The craft can be much more independent - my laptop has more processing capability than the entire Apollo program had. But it will still cost more than landing on visible side with line of sight communications only.

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18 minutes ago, Pawelk198604 said:

I know that but they can just place relay on Moon orbit.

There were no relays those days. And even today the relay had to be overhead in time (besides the need of a proper rocket).

They landed near the terminator line because they had to eyeball the last meters down and that is best done when there are shadows as a visual reference. And they landed towards earth to be able to assist in case of difficulties (and to have the show live of course).

 

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11 minutes ago, monophonic said:

my laptop has more processing capability than the entire Apollo program had.

Including the computers on the ground, and entirely in the realm of "possibly more than all the computers existing at that time on the entire Earth combined".

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17 minutes ago, Shpaget said:

 "possibly more than all the computers existing at that time on the entire Earth combined".

OT, i wouldn't go that far (those were the days of the mainframes, ibm 360/370 and clones, steampunk by our measurements :-)), but, indeed, the massive power of today's 8*4GHz chips plus the massive parallel power in a decent gpu allow real time realistic rendering and simulation games in high resolution.

But what do we do with it ? Browse stuff on the internet :-)

 

Edited by Green Baron
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Let's not forget the science hardware that the astronauts left on the surface, namely the Lunar Laser Ranging Reflectors. To my knowledge there are 5? of them, and have been used in enormous lengths to discover or reaffirm things about our system. It was discovered that the moon is drifting away at three and a half centimeters per year, they tested the accuracy of Einsteins relativity equations.

 

But there are even more reasons for them to land on the earth-facing side, cost of ensuring communications has already been brought up. But I think there was a deeper cultural reason for landing on the near-side. I can point a telescope and show people "see that really bright crater on the left? Apollo 12 and 14 landed just south of there" That's a level of understanding that you can not get by just looking at a map.

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17 minutes ago, Green Baron said:

OT, i wouldn't go that far (those were the days of the mainframes, ibm 360/370 and clones, steampunk by our measurements :-)), but, indeed, the massive power of today's 8*4GHz chips plus the massive parallel power in a decent gpu allow real time realistic rendering and simulation games in high resolution.

But what do we do with it ? Browse stuff on the internet :-)

 

I did some ballpark math before posting it, so here's what I came up with:

NASA used IBM 7090 for the Mercury and Gemini program, and even during the early Apollo. 7090 could do roughly 100 KFLOPS, while modern CPUs easily get into the 100 GFLOPS (so a factor of a million). I doubt there were a million of 7090s, so at the beginning of Apollo, my statement could very well be true. Sure, the later 360 is faster than 7090, but modern GPUs go into the TFLOPS territory.

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4 hours ago, Pawelk198604 said:

I know that but they can just place relay on Moon orbit.

Moon orbits are a menace, viciously unstable. The proposal was to put it at an Earth-Moon Lagrange point instead, but funding for such an op was pulled along with funding for Apollo 18-21. Other than that, there was no real obstacle.

Lunokhod 2 kinda reached the dark side by operating very near the limb.

3 hours ago, Green Baron said:

OT, i wouldn't go that far (those were the days of the mainframes, ibm 360/370 and clones, steampunk by our measurements :-)), but, indeed, the massive power of today's 8*4GHz chips plus the massive parallel power in a decent gpu allow real time realistic rendering and simulation games in high resolution.

But what do we do with it ? Browse stuff on the internet :-)

https://www.xkcd.com/676/

Edited by DDE
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 Apollo couldn't access the interesting far side areas like the aitken basin, only areas which were basically the same as areas they could reach on the near side. There just wasn't a compelling reason to do it.

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I believed a far side landing was one of the myraid of proposed missions for the later cancelled apollo missions. The CM would serve as comms relay when passing overhead, but there certainly would've been a lot of alone time on that mission.

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Imagine how the conspiracy theorists would have responded to a landing on the far side, where no one could possibly see the site from Earth!

Anyway, I won't be surprised if future science missions do go to the far side. It obviously has a very different geologic history than the near side, with almost none of the big basalt flow "marias".

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56 minutes ago, mrfox said:

I believed a far side landing was one of the myraid of proposed missions for the later cancelled apollo missions. The CM would serve as comms relay when passing overhead, but there certainly would've been a lot of alone time on that mission.

They probably had needed an extra satellite or two for constant coverage, harder but not significant so, China plan to land an rover on backside. 
Geology is different, some theory that earth had an second small moon at a L3 or L4 who impacted on the backside some million year after the primary impact. 

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7 hours ago, Pawelk198604 said:

I know that but they can just place relay on Moon orbit.

Nothing is impossible for the man who doesn't have to do it himself...

The main question is: why?

It's not like landing on the moon wasn't a challenge. “A small step for a man, a giant...”  “Hey Neil, bro! Save that for later, will ya? You guys did NOTHING, you just landed on the near side of the moon. EVERYONE can do that!”

Without joking around, there wasn't anything NASA would achieve by landing on the far side, at the price of jeopardizing a mission (so much more complexity, so many more things to go wrong). With a lack of certain benefits, either on the size of prestige and on the side of scientific gains, it simply wasn't worth the risk. Keep in mind that the scientific reasons we have now to go the far side probably didn't exist fifty years ago, as we knew far less about the moon (the very moon missions have changed that).

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On 19.07.2017 at 0:10 AM, DDE said:

Moon orbits are a menace, viciously unstable. The proposal was to put it at an Earth-Moon Lagrange point instead, but funding for such an op was pulled along with funding for Apollo 18-21. Other than that, there was no real obstacle.

Lunokhod 2 kinda reached the dark side by operating very near the limb.

https://www.xkcd.com/676/

 

But why Lunar orbit are so unstable?

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48 minutes ago, Pawelk198604 said:

 

But why Lunar orbit are so unstable?

Because the moon is small and lumpy, it's gravitational field is not evenly distributed. In other words, gravitational force depends not just on your distance to the center of the moon, but also on where (lat/lon) you are.

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57 minutes ago, Pawelk198604 said:

 

But why Lunar orbit are so unstable?

 

5 minutes ago, Kerbart said:

Because the moon is small and lumpy, it's gravitational field is not evenly distributed. In other words, gravitational force depends not just on your distance to the center of the moon, but also on where (lat/lon) you are.

Also there's a huge mass nearby that goes around the Moon (from its perspective) once a month.

The Moon is so big and so close that it pulls the oceans toward it visibly on the near side (and the Earth away from the oceans on the far side). Imagine what the Earth does to the Moon.

Sure it's not enough to send you careening into space or anything, but over time that takes its toll on an orbiter.

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That's on high orbits. Earth pulls the blanket to herself.

Low orbits are unstable due to mascons mass concentrates — masses or more dense rock material under the largest lunar seas and craters (there are several tens of them).
The craters (including seas) are result of hits of exttralunar bodies, and every hit compressed the rock beneath making it become more dense minerals.
These concentrates disturb the low orbit a lot, making it 2d-potato-shaped.

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I guess the problem was because of lack of relay sats, and any ways to put them (and justification to do so). You could, theoretically, deploy them on every attempt and only use them for a single attempt (so no need of orbital keeping); but it'd be waste of resource (back then) and still bulky (today). I'm not sure on the possibility of fitting cubesats (3U perhaps ?) with propulsion and relay comms on say, Apollo LM in the place of the satellites that they deploy for scientific research, but basically it's not possible back then and the main thing is not available today. You can bypass the problem by having comm sat things on Earth-Moon L4/L5 and L2, but I'd like to see one other satellite doing so first. Manned spacecraft are not easy; you know that dreams of Mars pretty much existed since people think of rockets but no-one is committing to it. If, somehow, SLS were to be real, maybe lots of you need to write to your representative that we do need one mission to the far side of the Moon. And then hope they hear you.

Edited by YNM
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8 hours ago, YNM said:

I guess the problem was because of lack of relay sats, and any ways to put them (and justification to do so). You could, theoretically, deploy them on every attempt and only use them for a single attempt (so no need of orbital keeping); but it'd be waste of resource (back then) and still bulky (today). I'm not sure on the possibility of fitting cubesats (3U perhaps ?) with propulsion and relay comms on say, Apollo LM in the place of the satellites that they deploy for scientific research, but basically it's not possible back then and the main thing is not available today. You can bypass the problem by having comm sat things on Earth-Moon L4/L5 and L2, but I'd like to see one other satellite doing so first.

Well, if anything, there is a history of chucking cubesat-like spacecraft into Lunar orbit from passing manned ships.

Apollo_15_Subsatellite.jpg

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