Author Topic: Earth to Orbit with a Space Bungee  (Read 15003 times)

Offline stefan r

  • Full Member
  • *
  • Posts: 122
  • pennsylvania
  • Liked: 23
  • Likes Given: 51
Re: Earth to Orbit with a Space Bungee
« Reply #60 on: 08/14/2017 09:59 pm »

So how would you guys get things off the Earth, using non-Earth-based resources?

You don't.  You use Earth-based resources to get things off the Earth.  Bringing non-Earth-based resources into the Earth's gravity well to get out of the gravity well makes no sense.

It can make a lot of sense.  An orbital ring has been described and there are several versions. 

Momentum exchange tethers also have detailed description.  They are not likely to reach into the atmosphere.  Velocity at the end of the tether will be much higher than surface velocity.  But they could haul material out of Earth's gravity well.  Tethers can take momentum by deorbiting junk satellites or deorbiting mass from asteroids or the moon.  Rockets attached to tethers can burn lunar oxygen. 

A space station burning or accelerating lunar oxygen is also using outside resources to rise higher in the gravity well. 


Part of the problem with this discussion from my point of view is that you aren't accepting my central premise for the point of this discussion, that water is plentiful on the Moon. I understand this is not currently an Established Fact, but I think the possibility that it soon will be is enough to start thinking about what to do with it.

It might help if you distinguished between "water" and "hydrogen containing minerals".  Pottery makes call the clay "bone dry" before they put it in the kiln.  Then they heat it slowly to boil off the water.  Then they raise the temperature to remove chemically bound water from the surface of particles in the clay. 

Bauxite or gibbsite (Al(OH)3) is a mineral.  I would say that batch of bauxite can be dry and "not have any water in it".  If you process bauxite into aluminum metal there must be some oxygen and hydrogen atoms around. 

Suppose we had a chunk of pure gibbsite larger than Texas conveniently located at the moons equatorial surface.  A lunar colony will still have better uses for hydrogen then sending it into Earth's atmosphere.  Extracting hydrogen from gibbsite is painful.  The hydrogen would be needed in lunar greenhouses and could be used to launch away from Earth. 

Offline bradjensen3

  • Member
  • Posts: 50
  • Tulsa, Oklahoma, USA
  • Liked: 4
  • Likes Given: 0
Re: Earth to Orbit with a Space Bungee
« Reply #61 on: 08/14/2017 10:35 pm »
Recent water on/in the Moon article https://phys.org/news/2017-07-scientists-spy-evidence-moon-interior.html

No, I wasn't thinking of extracting hydrogen and oxygen from bauxite on the moon.
Not That There's Anything Wrong With That.

« Last Edit: 08/14/2017 10:37 pm by bradjensen3 »

Offline meberbs

  • Senior Member
  • *****
  • Posts: 3096
  • Liked: 3379
  • Likes Given: 777
Re: Earth to Orbit with a Space Bungee
« Reply #62 on: 08/14/2017 10:46 pm »
Recent water on/in the Moon article https://phys.org/news/2017-07-scientists-spy-evidence-moon-interior.html

No, I wasn't thinking of extracting hydrogen and oxygen from bauxite on the moon.
Not That There's Anything Wrong With That.
The adjectives in that article may have caused you to miss the number. In the parts that have water, what they found is 0.05 % by weight or 1 part in 2000. This means processing 2 tons of regolith to get 1 liter of water. This basically translates to your "plentiful cheap water" assumption being something that will never happen.

Of course most of the recent objections to your idea have moved past this and just pretended that there is an ocean on the moon to point out why the rest of your concept still will not make sense.

Offline bradjensen3

  • Member
  • Posts: 50
  • Tulsa, Oklahoma, USA
  • Liked: 4
  • Likes Given: 0
Re: Earth to Orbit with a Space Bungee
« Reply #63 on: 08/14/2017 10:57 pm »
If we need more water on the Moon, why not bring it from Ceres?

Ceres has a lot of water, and it is probably available thru ice volcanoes.

Ceres has 1/30th Earth gravity and an escape velocity of .51 km/second.

Use water from the Moon with a NTR engine giving specific impulse of 420 to head for Ceres.

Use automated rockets with hydrogen peroxide engines with spcific impulse of 140 to send giant water balloons back to the Moon. Aim for a crater with high walls all around just entering the 14 day lunar night. Grab up some significant percentage of the water as it cools down.

Or aim near the poles and let the moon 'distill' the water intos its ice caches.


Tags:
 

Advertisement NovaTech
Advertisement Northrop Grumman
Advertisement
Advertisement Margaritaville Beach Resort South Padre Island
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
0