# SPACE: Lunar Warfare? (was Re: Lunar Billboard?)

Mark Grant (mark@unicorn.com)
Sat, 4 Jan 1997 17:32:35 +0000

On Wed, 1 Jan 1997, Michael Lorrey wrote:

> Additionally, being on the moon gives one a first strike advantage. you
> can see the other guy coming 239,000 miles away,

Are you sure of that? A stealthy warhead launched from the far side of the
Earth would be almost impossible to detect without surveillance
sattelites. You certainly wouldn't be able to find it easily after the
launch. With a big investment you might be able to spot the warheads with
a radar cross-section the size of a marble that the Earthers put in lunar
orbit as a precaution, but could do little about them if they put a
hundred thousand real marbles up there as camouflage.

> and have plenty of time
> (two to three days) to get enough rocks in flight

What if the humans have a smaller mass-driver in orbit and use that,
rather than rockets, to shoot back at you? Also, how much power do you
intend to have available? AFAIR you need five or six km/s to get from the
lunar surface to Earth, so launching a one-ton rock will take about 14 GJ
if your launcher is 100% efficient (hitting you with a fusion bomb from
Earth orbit in one day would probably take more like 100 GJ, but they
wouldn't need many of them).

Hmm, so with a 1GW nuclear reactor you'd be able to launch four per
minute, or about 18000 before you're nuked to rubble. At 10kt per rock
you're only talking 180 megatons total, and I'd like to see the
calculations that show a 10kt yield per rock. I don't have the conversion
ratio from joules to tons of TNT handy, but my rough guess based on what I
remember of the conversion efficiency in atomic bombs is more like 10
tons. I might be wrong.

> to pulverize the
> entire planet before your own launcher gets taken out.

Let's see... even if you're right, the serious destruction area of a 10kt
explosion is around 4 km^2. So you can destroy or severely damage about
70,000 km^2 of Earth, or about 0.00001% of the surface or 0.00004% of the
land area. Bad, but not as bad as WWII, particularly as most cities will
be empty by the time your rocks hit them; if you can see missiles coming
from Earth then they can see your rocks a day before they land. In
comparison, the entire inhabited area of the moon will be nuked until
they're just making the glowing rubble bounce and any survivors will be
ruthlessly hunted down and executed.

Feel free to prove my calculations wrong, but I'd have to be wrong by
several orders of magnitude for your position to be realistic.

> remember, terran nations would need Saturn V like launching capability
> to do anything feasible in a lunar attack,

The Saturn V was so large because it had to get several tons to the moon
and back. What was Ranger launched on; an Atlas-Centaur? You could
probably fit a large fission bomb or small fusion bomb into the mass of a
Ranger probe.

> and if the corporation
> developing the moon controls the best launch capability, terran nations
> would be in a serious conundrum.

That seems like a highly unrealistic "if" to me. If any corporation can
build a launch vehicle that would make a lunar colony realistic then many
others will be queueing up to buy them or build their own. Governments
are likely to be among the first customers.

> Lunar construction also lends itself to bomb proofing. As a lunar
> habitat would need to be protected from the hardest radiation, it would
> neccessarily be at least 6 feet under the lunar soil or rock surface.

Well, the RAF built bombs in WWII that would penetrate a couple of hundred
feet underground before exploding, and the USAF planned to use the
original 'gun' atomic bomb to destroy Soviet submarine pens because it was
so tough it could punch through a huge amount of concrete before
exploding.

Basically, if you can see it you can probably destroy it; why do you think
that in WWIII the US president would be in a 747 and not an underground
bunker? The mass-driver, of course, will be km long and easy to destroy;
even a kamikaze attack with a lunar transport would knock it out for days.
I did mention that the CIA had agents in your colony just in case you
thought of this, didn't I?

> Any inhabitable space would be an automatic bomb shelter. So even if the
> Earth takes out your gun, you still have the rest of your infrastructure
> and population.

Even if they did survive they would be just sitting there waiting for the
Earthers to arrive and hang them for war crimes... Hmm, wonder if you can
hang people in lunar gravity?

Seriously, your scenario seems to rely on a complete lack of opposition
from Earth, in which case it would work. But that's not going to happen.

Here's my scenario: You threaten to attack Earth. I say 'Make my day...'
My agents who are working on mass-driver maintenance reverse the control
inputs in the second half of the tube. You fire your first rock, and it
slams into the side of the tube at 2500 m/s. If your calculations are
correct, then that's equivalent to an explosion of more than 250 tons of
TNT two-thirds of the way along the mass-driver. If I'm correct then it's
still bad news. You can't launch anything until it's fixed.

You refuse to surrender and rush around trying to fix it. My agents
working on your nuclear reactor blow up the cooling system with survey
charges provided by the industrial espionage agents working in your survey
teams. My navy arrives three days later and nukes the mass-driver. You
launch a missile at my flagship and I nuke all your surface installations.
You surrender. Your colony is taken over and most of the survivors go to
jail.

Mark

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