Sanity check for earth launched moon pod

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Discussion Overview

The discussion revolves around the feasibility and calculations related to a proposed moon pod concept, including its propulsion and structural requirements. Participants are providing feedback on mathematical accuracy and theoretical implications, with a focus on the concept of escape velocity and comparisons to space elevator designs.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant presents a moon pod idea and requests feedback on the associated mathematics and concepts.
  • Another participant identifies significant inaccuracies in the initial calculations, including the distance to the Moon, Earth's radius, surface speed, and escape velocity.
  • There is a suggestion that the proposed design resembles a space elevator but lacks the necessary height to achieve orbit or escape velocity.
  • A participant questions whether the escape velocity mentioned is from the surface and notes that it decreases with altitude.
  • Concerns are raised about the physical feasibility of constructing a tower of the proposed height required for the concept to work.

Areas of Agreement / Disagreement

Participants generally agree on the inaccuracies in the initial calculations and the impracticality of the proposed tower height. However, there is no consensus on the overall feasibility of the moon pod concept itself, as it remains a thought experiment.

Contextual Notes

Limitations include unresolved assumptions about propulsion methods, the feasibility of achieving necessary velocities, and the implications of building structures of extreme height.

sammorgan101
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Hi I've been scratching my head late into the night, and come up with some ideas for a moon pod, I could use a sanity check on the maths and basic idea. Very interested to hear feedback. Post comments here or on my blog...

http://wellybob.blogspot.com/2012/01/travel-to-moon.html

Thanks in advance
 
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Your factual numbers are off by an order of magnitude. I assume "M" is metres.
Distance to Moon is 360,000,000 metres, not 36000000M. Radius of Earth is 6,353,000 metres not 635300M.

The speed at Earth's surface is 447m/s, not 46m/s.

Earth's escape velocity is 11,200m/s - a little higher than the 49m/s you calculated you'd achieve.

And you've done all this to gain a 6% increase in velocity - from 46m/s to 49m/s. Is it worth it?
Finally, what you're making is a junior version of a space elevator without the top half. Considering your tower would have to be 35,000 km tall to have its top achieve orbit, it will have to be even more ridiculously tall to gain enough speed to break orbit to go the Moon.

Seriously, look up space elevators.
But other than that, it looks great! Where do I book! :biggrin:
 
Last edited:
Thanks for the corrections, was done after a few whiskeys last night. Yes I saw the space elevator a while ago, very interesting, this was more a thought experiment in propulsion. Is the escape velocity that you quote from the surface? That's the next bit I need to look into.

Thanks Dave
 
sammorgan101 said:
Is the escape velocity that you quote from the surface?
It is, and yes the escape velocity drops with altitude but the problem is that, with your method, you don't each reach geosync orbit without a tower that is 35,000 km tall, let alone escape velocity.

It is physically impossible to build a tower that tall. Thus, the space elevator.
 

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