Discussion on question by Mohammad Fajar: Size of vehicle needed to leave moon gravitational pull?

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10:47

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Q: Size of vehicle needed to leave moon gravitational pull?

There are some skeptical questions in my mind about moon landing: Compared to distance to ISS, moon very far away from us, so it is need much of fuel to get to there, so it is reasonable to say that rocket that bring human to the moon much much bigger that bring them to ISS. How high altitude...

nasa

BobTheAverage

Hello and welcome to Skeptics.SE. Your questions are interesting ones, but here at Skeptics.SE we only answer questions that have a notable claim, something someone important has claimed to be true. Many people have said many things about the moon landing, and how it might have been fake. If you find the claims that inspired your question, and quote them here, we can answer your question.

Your question might be better asked on Space.SE, a StackExchange site about space exploration.

hdhondt

1. Most fuel is used to get from earth to LEO. From there to the moon requires less additional speed, and the craft is much smaller. 2. You never leave earth's gravity. 3. Ditto. As the moon has 1/6th earth gravity and no atmosphere, far less fuel is needed.

Mohammad Fajar

But the space craft and astronot at least have 400 kg of Weight (because its Weight 3 tons on earth), how to lift object 400 kg of weight to leave moon gravitational pull with minimum amount of fuell?

At least we must attain reasonable altitude and from there we Drive spacecraft to escape velocity of moon, and thats need much of fuell

Also we need specialized rocket so its stable when leaving moon surface, so there are two type of rockets to achieve moon landing, first the rockets that needed to bring human leave moon gravitational pull that is to attain high altitude and Drive to escape velocity of moon, and second rocket to carriage the first rocket and also human to leave earth gravitational pull...

Asher

Have you tried looking up the design of the Saturn V rocket and Apollo orbiter and landing craft? Examining the vehicles which actually performed the feat may help direct your questions. Currently they can all be answered with the rocket equation and calculus, but I doubt that would satisfy you.

fredsbend

space.stackexchange.com

Mohammad Fajar

10:47

You can compare this with the situation when modern jet fighter need to make vertical landing above aircraft Carrier, it is need specialized rocket and experienced pilot that bring them from horizontal movement with velocity up to 800 km per hours to vertical landing... And for moon landing it is very hard than this, because moon Orbital velocity is 2 km per second, thats very fast.. and when you see photo of lunar module, they just using old obsolete rocket mechanism that many I saw demonstrated on tv using bottle of coca cola..

Impossible for them to make soft vertical moon landing, because beside they not experience pilot, that lunar module just using old technology and need to adapt the mechanism that never succesfully applied until recently....

You, know how to bring astronot from ISS to earth surface, they using parachute and also to landing them on ocean.... If you try to Make a free fall on moon with acceleration 1.6 m/s^2, it is needed ten second to make you achieve velocity 10 m/s, and it is very hard when you hit the moon surface...

hdhondt

Try reading en.wikipedia.org/wiki/Apollo_Lunar_Module and en.wikipedia.org/wiki/Saturn_V , including the references. That will give you some idea how it was done. For background knowledge, try any good physics textbook.

Loren Pechtel

@MohammadFajar Landing a Falcon 9 is much harder than landing an Apollo LEM. The Falcon 9 is much taller--try to balance a baseball bat on your hand (vertically) vs balancing a ball on your hand--note that the early Falcon 9 losses were due to not being straight. Also, lunar gravity is 1/6th of ours, things happen slower so you don't need to be as precise. They also had the ability to hover, the Falcon 9 has no choice but to perform what's generally known as a suicide burn (as in you get it almost perfect or you die.)

While I agree that the questions involved belong on space.stackexchange.com it's not really off topic--he's obviously attempting to deal with some of the moon-landing-is-a-hoax claims--the notable claim requirement is met.

Shadur

@lorenpechtel He's not trying to deal with hoax claims, he's making them: He literally says "There are some questions in my mind". And judging by his "questions" they all stem from his lack of understanding of rocketry or any of the physics involved, so space.se is the correct place for him.

If all of the above recommendations and explanations fail you, crack open youtube and look for pretty much any Kerbal Space Program playthrough of a Mun landing and Kerbin return. Note the extreme size difference between the rocket that launches from Kerbin and the module that returns from the Mun surface.

Mohammad Fajar

Falcon 9 just for ISS, whereas ISS just 200 miles from earth surface, but for appolo 11 they needed to landing on moon that 124000 miles away, I bet if you try to makes a vertical landing in current technological situation in rocket development it is very hard, and they never succesfully to make such a rocket to simulate a vertical landing on earth surface during 1966 era, let alone to make it happen at the moon surface,

Can you give some video when they try to simulate about vertical landing during 1966 era, because impossible to makes astronot adapted with that situation for the first time.... It is like how make a sky diving wihout guide for the first time, you know thats very dangerous, let alone to make a capsule with 3 tons Weight to have a soft landing on moon for the first time..

Erik

It doesn't make sense to be skeptical of things you don't understand. You should be in learning mode, not questioning mode. Read about how (astro)physics work rather than trying to debunk a thing with your currently extremely limited understanding.

Mohammad Fajar

10:47

I dont wanna try to debunk something, I need more concrete proof, If you can give a proof how vehicle during 1966 era can achieve vertical landing from velocity 2 km per second,it is enough for me.

hdhondt

You want a video showing moon landing simulators? Try youtube.com/watch?v=rbdJPuq08Wc

Mohammad Fajar

Yes but that vehicle failed and burned, also not come from high horizontal velocity to "succesfully" vertical landing

Oddthinking

@MohammadFajar Good news! There was an experiment where they tried to build a machine with the technology available in the 1960s, to see if it was really feasible to send a rocket to the moon, have people land on it, and bring them back. It precisely addresses your "skepticism". It worked, so you can now feel comfortable it is feasible.

The experiment was called "Apollo 11", and they ran it in July 1969.

Here is your proof.

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