How many pounds of fuel were used to escape earth gravity and how much was used to escape moon gravity?

Question

How much fuel was used to prevent the lunar module from crashing into the moon?

It is common knowledge that the moon has no atmosphere and has 1/6th earth gravity.

Jason T:

Masses of lunar module:
Ascent module: 10,024 lb or 4,547 kg
Descent module: 22,375 lb or 10,149 kg
Total: 32,399 lb or 14,696 kg

The forces on craft are its weight (downwar) and thrust (upward). The difference between these forces is net force, which should be directed upward, for, clearly, the craft requires an upward acceleration in order to decrease downward speed.

F(net) = ma = T − mg.

Thence,

T = ma + mg = m(a+g).

Of couse, g is in this case 1.6 m/s². Effective acceleration a can be found from

assume v initial is 28.3 m/s^2 (from another yahoo question)

a = vo² / 2h = 28.3² / 350 = 2.288 m/s².

Then,

T = m(a +g) = 14696kg ( 2.288 + 1.6) = 57138 kgm/s^2.

That means the lunar module needs to burn 57000 kg of fuel per second to brake...it could take a couple of hundred of thousand pounds of fuel to prevent it from crashing into the moon...

To escape moon gravity..just use your number of 6 million /6 = 1 million pounds

Answer 1

The Saturn V burned in total about 5.95 million pounds of propellants to send the spacecraft to the Moon. The lunar module descent stage used about 18,000 pounds of fuel to brake it from lunar orbit to a soft landing on the surface. The ascent stage used about 5,187 pounds of fuel to take off and return to lunar orbit, then the Apollo CSM used around 18,000 pounds of fuel to break out of lunar orbit and head back to Earth.

The vast differences in fuel usage are of course due to the different sizes of the payload in each case. The Saturn V had to bost a fully fuelled Apollo spacecraft and the entire third stage of the launch vehicle to a translunar trajectory, while the LM needed only to land itself on the surface and the boost a comapratively tiny, lightweight cabin with two men back to lunar orbit.

[Edited to add]

>>To escape moon gravity..just use your number of 6 million /6 = 1 million pounds<<

I suggest you think a bit harder about that. I won't even bother addressing your equations when you make such an elementary error.

The fuel requirements of a Saturn V were to boost a fully fuelled and manned Apollo spacecraft stack to a speed of 25,000mph against Earth's gravity. That entails boosting a 363' tall rocket weighing over 6.5 million pounds off the pad. The requirements of the lunar module ascent stage were to boost itself and two crewmen to a speed of less than 4000mph against lunar gravity. Why do you think that boosting a much smaller craft to a much lower speed against much lower gravity requires 1/6th the fuel of the Saturn V launch? And why do you think you can do such a straighforward conversion when you haven't bothered to find out the different densities of the different fuels, or the specific impulse of the different fuels?

Answer 2

The apollo launch vehicle was designed to boost the apollo capsule to the moon. That is, it was designed to have sufficient speed to get to the moon. Apollo launch vehicles were really only used to go to the moon. Other missions used Saturn V boosters (to go to the other planets) and I am not sure what they used to get to low earth orbit (I assume the gemini launch vehicle). The space shuttle was designed to go into low earth orbit. Though it can launch satelites into a higher orbit. All the space shuttle would need to get to the moon is more power. This could come from additional fuel. It could also launch a vehicle that could go to the moon. Really the main issue is not getting there (as some people think) but the time it would take. Many launches now plan well ahead of the mission and use gravity sling shots to take unmanned probes out to the planets. This uses less fuel. Basically the long and short of it is that if we wished to return to the moon we would need to build a new and more appropriate launch vehicle with a lot of talk about assembling it in space, rather than launching it from earth.

Answer 3

you will need to leave earth at a speed of roughly 26,000 miles per hour.

Answer 4

3210000

Answer 5

dunno