Here’s a handy map of the trajectory:
And here is an interactive web app that shows each stage:
http://spaceflight.nasa.gov/history/apollo/apollo_mission.html
Yep. This part:
is where it all breaks down.
OK, so a space craft that leaves earths atmosphere going 24,000 mph is actually not moving forward at all (relative to the universe) but 43,000mph in the opposite direction. 24,000mph slower than the earth is pulling the moon.
So technically you are waiting for the moon by traveling the same direction as the moon at a slower velocity than the moon. The moon eventually catches up. Does that make sense?
This whole topic started as a friendly conversation among some of my friends (none of us being in the scientific field but all with huge imaginations)
Thanks for the input
Anybody interested in this stuff should get their hands on the Apollo News Reference (available here, apparently, but I didn’t check the link). It was published by NASA to be a comprehensive reference document for the press at the time, and so it’s got basically everything you’d want to know about the Apollo mission and spacecraft, pitched at the level of an educated, interested layman.
There’s a Lunar Module News Reference and Saturn V News Reference available on the web as well.
–Cliffy
Besides other considerations, if you cancelled the momentum imparted to you from the Earth to “stop” and wait in space, since you are no longer orbiting the Sun, you would begin to fall into it. Waiting for the Moon to come around would be the least of your problems.
Your problem is that you are assuming a zero rest frame ‘relative to the universe’ that the rocket can suddenly magically stop relative to. There is no such thing. All movement is relative, and there is no preferred frame of reference that can be declared to be not moving relative to the universe.
The Earth isn’t pulling the Moon along with it in orbit. The Moon is orbiting the Earth, and the two of them together are orbiting the Sun, which it itself orbiting the center of the galaxy, which is itself moving at some speed relative to other galaxies in the universe. When the Apollo craft fires its third stage engine for trans-lunar injection, it is still in orbit around the earth - just a highly elliptical orbit which will bring it near the Moon, where the Apollo service module engine will be used to put it into an orbit around the Moon. The math works out regardless of whether you consider the Earth, the Sun, or the Moon to be stationary.
Why did it take 3 days to get to the moon?
Lot of that pesky construction along the way.
Well the construction, and the fact that we never really went to the moon in the first place.
D, and of course, R
Upon seeing the resurrector of this thread did anybody else go;
“Na na, na na, na na, na na, shampoo, towel” or was that just me?
No, we did. But we drove there, fool.
You don’t need to obtain escape velocity to escape the gravity of the earth*, if you had enough time and fuel you could do it at 1mph.
Escape velocity is what is needed to be ‘shot’ from the surface with one burst of speed, it does not come into play for continuously powered rockets.
*technically way out in orbit you will need to exceed the escape velocity to escape, but at that point that far out the escape velocity would be only 1mph.
“Mouths full of chocolate
Covered cream.”
It was arguing over stopping and asking directions that REALLY took up the time!
~VOW
Why did it take 3 days to get to the moon?
Because it’s really far away.
Is this a zombie thread that got re animated
Declan