Author Topic: Net on the Moon  (Read 1730 times)

Offline Spacenstuff

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Net on the Moon
« on: 07/13/2018 03:06 pm »
Hi,
Just wanted to get a professional view if there would be a point of setting up a net to catch padded/protected robots to lower propellant requirements for Moon landing?

How efficient would this be? Would it be economical?

Thank you

Offline johnfwhitesell

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Re: Net on the Moon
« Reply #1 on: 07/13/2018 03:18 pm »
How efficient would this be? Would it be economical?

Space travel involves changes of speed of kilometers per second.  Here is a nifty chart: http://www.projectrho.com/public_html/rocket/images/spacemaps/RocketCatUniverse2.png

I could see a net being useful for something of perhaps a hundred meters per second.  So it's pretty small compared to the scale we are talking about.  I think it would probably more sense as a safety feature then as anything else, the job of the net isn't to slow things down but to soften the impact if something goes wrong at the last second.

Offline Spacenstuff

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Re: Net on the Moon
« Reply #2 on: 07/13/2018 03:43 pm »
That's a great chart. Yeah, I had my suspicions... At least here I got my answer in matter of minutes  ;)


Offline speedevil

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Re: Net on the Moon
« Reply #3 on: 07/13/2018 03:49 pm »
As an addendum, some things don't need to be landed intact, and it's somewhat plausible to hard-land them.
For example, raw carbon powder.
(carbon is moderately rare on the moon)

Offline Spacenstuff

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Re: Net on the Moon
« Reply #4 on: 07/13/2018 04:27 pm »
Create robots that can reassemble themselves like Terminator in one of the movies - don't need any propellant to land :)

Offline EMurphy85

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Re: Net on the Moon
« Reply #5 on: 07/16/2018 01:43 pm »
Or just set up an assembly facility on the surface and hard-land the materials it needs

Offline johnfwhitesell

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Re: Net on the Moon
« Reply #6 on: 07/16/2018 02:50 pm »
Or just set up an assembly facility on the surface and hard-land the materials it needs

How hard we talking?

Offline speedevil

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Re: Net on the Moon
« Reply #7 on: 07/16/2018 05:41 pm »
Or just set up an assembly facility on the surface and hard-land the materials it needs

How hard we talking?
Carbon dust can easily take impact to lunar escape velocity, with negligible evaporation.
Tuning the particle size spectra may be interesting.

Ice, cooled to 20K will about half evaporate on going from LLO->impact. Again, tuning particle size so you get significant enrichment on your target will be fun.

Once you start going below that velocity, there is limited point in hard-landing, as you need to spend most of the propellant anyway.


 

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