4 ms·

> provide us with mineral and energy wealth. Gravity: Am I a joke to you?

actionfromafar 4y ago
Iff the energy can be extracted on the moon (water + solar + rock) and equipment be built there, there is only the gravity of the moon to overcome, which is low.
- Teever 4y ago
  Due to the lower gravity Lunar Space Elevator with existing technology[0] to greatly simplify the process of resource return and we could easily use Moon based solar power to mine and refine minerals. [0] https://en.wikipedia.org/wiki/Lunar_space_elevator#Fabrication https://en.wikipedia.org/wiki/Lunar_space_elevator#Fabricati...
- marginalia_nu 4y ago
  Some flies in the ointment: * The moon is frequently bombarded by rocks of different sizes (most of this stuff burns up in our atmosphere). Any permanent structure needs to essentially survive being shot at by something at between mach 10-50[1], maybe just a tiny spec of dust, a pellet, or something big as a truck, happens every once in a while on the moon with no advance warning (except during meteor storms, when it's more like the battle of Somme). This probably rules out using permanent installations like catapults/mass drivers, space elevators, or similar to escape the planet. * You still need to actually land the stuff on earth. Can't just hurl space rocks at the planet. Anything big enough to survive re-entry is going to make a big crater. * You need to bring the stuff needed to safely bring stuff back to earth up into space for every "shipment". This is probably more costly than launching the stuff from the moon. [1] https://www.nasa.gov/centers/marshall/news/lunar/overview.html https://www.nasa.gov/centers/marshall/news/lunar/overview.ht...
  - actionfromafar 4y ago
    Given how much flak WW2 bombers could take and still fly, I'm not overly worried. Just build redundancy into the design. For wheeled vehicles, add more wheels. For solar panels, put them in a grid spacing, etc. Since the moon has a vacuum, whatever is launched from there has no drag. Make the payload in winged form, skip-bounce on the Earth atmosphere, add some ablative shielding, and Bob's your uncle.
    - marginalia_nu 4y ago
      This is a bit different from flak. The intuition you have for kinetic energy based on living on earth doesn't capture just how insanely high the kinetic energy of something going at 70 km/s is. It's probably better to conceptualize it as heavy artillery than a projectile in terms of the damage its capable of inflicting.
      - actionfromafar 4y ago
        Sure, but it will also go straight trought many things, not impart all of its kinetic energy into whatever it punches through first. The ISS has survived quite a long time in much the same environmental conditions as stuff on the moon offer, and the ISS also needs to worry about keeping air inside. Just how dense are these rock showers do you reckon? After all, the moon has very old untouched features.
        marginalia_nu 4y ago
        The ISS can first of all move if something larger is detected. But the ISS has gotten hit, several times. But most of its cross sectional area is solar panels though so it's not been so bad. Another big difference is that if the ISS gets hit by anything with significant kinetic energy, it will just punch a hole clean through whatever it impacts. There is nothing that can absorb that sort of kinetic energy. This is in most scenarios good news. If a meteorite hits the lunar surface, the surface absorbs the kinetic energy, the surface and the meteorite evaporates, causing an explosion of molten rock moving at high velocities. This means even glancing hits or near misses can be devastating in a way they aren't when you are in orbit.

Iff the energy can be extracted on the moon (water + solar + rock) and equipment be built there, there is only the gravity of the moon to overcome, which is low.

Teever 4y ago
Due to the lower gravity Lunar Space Elevator with existing technology[0] to greatly simplify the process of resource return and we could easily use Moon based solar power to mine and refine minerals. [0] https://en.wikipedia.org/wiki/Lunar_space_elevator#Fabrication https://en.wikipedia.org/wiki/Lunar_space_elevator#Fabricati...
marginalia_nu 4y ago
Some flies in the ointment: * The moon is frequently bombarded by rocks of different sizes (most of this stuff burns up in our atmosphere). Any permanent structure needs to essentially survive being shot at by something at between mach 10-50[1], maybe just a tiny spec of dust, a pellet, or something big as a truck, happens every once in a while on the moon with no advance warning (except during meteor storms, when it's more like the battle of Somme). This probably rules out using permanent installations like catapults/mass drivers, space elevators, or similar to escape the planet. * You still need to actually land the stuff on earth. Can't just hurl space rocks at the planet. Anything big enough to survive re-entry is going to make a big crater. * You need to bring the stuff needed to safely bring stuff back to earth up into space for every "shipment". This is probably more costly than launching the stuff from the moon. [1] https://www.nasa.gov/centers/marshall/news/lunar/overview.html https://www.nasa.gov/centers/marshall/news/lunar/overview.ht...
- actionfromafar 4y ago
  Given how much flak WW2 bombers could take and still fly, I'm not overly worried. Just build redundancy into the design. For wheeled vehicles, add more wheels. For solar panels, put them in a grid spacing, etc. Since the moon has a vacuum, whatever is launched from there has no drag. Make the payload in winged form, skip-bounce on the Earth atmosphere, add some ablative shielding, and Bob's your uncle.
  - marginalia_nu 4y ago
    This is a bit different from flak. The intuition you have for kinetic energy based on living on earth doesn't capture just how insanely high the kinetic energy of something going at 70 km/s is. It's probably better to conceptualize it as heavy artillery than a projectile in terms of the damage its capable of inflicting.
    - actionfromafar 4y ago
      Sure, but it will also go straight trought many things, not impart all of its kinetic energy into whatever it punches through first. The ISS has survived quite a long time in much the same environmental conditions as stuff on the moon offer, and the ISS also needs to worry about keeping air inside. Just how dense are these rock showers do you reckon? After all, the moon has very old untouched features.
      - marginalia_nu 4y ago
        The ISS can first of all move if something larger is detected. But the ISS has gotten hit, several times. But most of its cross sectional area is solar panels though so it's not been so bad. Another big difference is that if the ISS gets hit by anything with significant kinetic energy, it will just punch a hole clean through whatever it impacts. There is nothing that can absorb that sort of kinetic energy. This is in most scenarios good news. If a meteorite hits the lunar surface, the surface absorbs the kinetic energy, the surface and the meteorite evaporates, causing an explosion of molten rock moving at high velocities. This means even glancing hits or near misses can be devastating in a way they aren't when you are in orbit.