A couple of random Apollo questions..

[intheshadow]

Hello all. Happy to be a part of the community. I've read and researched Mercury through Apollo for a number of years now but there are still some things I'd love to find answers to. Wanted to see if anyone could help.

1) I often read about talk about how dangerous it would be to land on the "far side" of the moon or how exploring the "far side" could be exciting. What I don't understand is... doesn't the moon rotate on its axis just like the earth? And if so, there really isn't a "far side" of the moon per se since all sides face the earth at some point in its rotation right?

2) Why didn't the astronauts need to be in their pressurized suits on re-entry? Also, did they only wear them during the launch simply to avoid the "bends" or was there another reason?

3) Why was weight of the CM/LM so important? They always said they "had to keep the weight down." I realize it takes more thrust to launch something heavier but couldn't they just build bigger rockets? And why did they take just enough fuel on the LM to land on the moon? Was having a couple hundred pounds of fuel as a reserve really that big a deal in the weight category?

4) How in the world did the engineers/scientists first discover the proper re-entry angle? Was it just process of elimination with unmanned probes to see which ones survived the trip back?

many thanks in advance!

 

[drwayne]

Hitting some of your questions as I have the time.

With respect to the "far side", the moons rotation is such that it rotates once on its own axis at the
same time that it orbits once around the Earth. This means that it always presents the same face
to the Earth. You will hear terms like "tidal locking" associated with this effect.

With respect to weight, there is a limit to how big (and how costly and complex) you can make your
launch vehicle, so growing the Saturn 5 to allow for a bigger CM/LM was not feasible. There was
by the way a safety margin on the LM fuel to allow for significant course corrections, as well as
various abort modes. As the Apollo 13 mission proved, despite it's constraints, it was a vehicle
with a lot of margin to it.

 

[highdobb]

Hello all. Happy to be a part of the community. I've read and researched Mercury through Apollo for a number of years now but there are still some things I'd love to find answers to. Wanted to see if anyone could help.

1) I often read about talk about how dangerous it would be to land on the "far side" of the moon or how exploring the "far side" could be exciting. What I don't understand is... doesn't the moon rotate on its axis just like the earth? And if so, there really isn't a "far side" of the moon per se since all sides face the earth at some point in its rotation right?

2) Why didn't the astronauts need to be in their pressurized suits on re-entry? Also, did they only wear them during the launch simply to avoid the "bends" or was there another reason?

3) Why was weight of the CM/LM so important? They always said they "had to keep the weight down." I realize it takes more thrust to launch something heavier but couldn't they just build bigger rockets? And why did they take just enough fuel on the LM to land on the moon? Was having a couple hundred pounds of fuel as a reserve really that big a deal in the weight category?

4) How in the world did the engineers/scientists first discover the proper re-entry angle? Was it just process of elimination with unmanned probes to see which ones survived the trip back?

many thanks in advance!

1: Google "synchronous rotation." Have you ever seen the far side of the moon before?! I would think the main reason for keeping the landing sites on the near side in the late 60's/ early 70's was due to communication...

2: It's my understanding they wore them during launch as a precaution in case of aborting a launch. Upon reentry you're in gravity's hands, no control beyond angle of reentry, therefore they aren't necessary. The capsule was pressurized for their protection.

3: It was approximately $3,800 per pound (adjusted for inflation) to launch something on the Saturn V. At 6.2 million pounds fully loaded, it was VERY important to keep weight/cost down. The more you bring the more fuel and bigger rocket needed. You can't be half way through building the rocket and add more weight, the whole thing would need to be redesigned!

4: No. Math is the key! With a great understanding of physics, gravity and the mental capacity to handle it, humans can do wonders ;-)