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Comment by wongarsu | Hacker News Reader

There was fear that if the Russians got to the moon first they might set up a base, and having a base they could shoot down any other landing attempt (literally, with guns mounted in their moon base). Thus the moon could become Russian domain, which would not just grant them great research opportunities but also a virtually unreachable weapons platform. (Remember that the first crewed space station was 2 years after the moon landing, and also Soviet)

On that basis the military was advocating for a moon mission years before Kennedy's speech. It's hard to tell if this actually played a big role in the decision to go to the moon, but it was the cold war after all.

Also the Soviet Union was winning most of the relevant milestones in space (first satellite, first animal in orbit, first human, first woman, first space walk, etc), and this was a great source of national pride. Beating them had great propaganda value.

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Shooting people from the moon is probably the least practical military endeavor ever seriously contemplated, and that is saying a lot.

The Cold War resulted in a lot of really nutty thinking so I can't rule it out entirely, but it's hard to imagine what such a base would look like, especially with 1960s tech.

Getting from the moon to earth is trivial when compared to launching anything from earth. Using some back-of-the-envelope calculation a Atlas B ICBM from 1959 has enough fuel and thrust to deliver over 5 tons of warheads from the moon to earth. If you launched from the far side of the moon I imagine early warning and interception aren't on the table with 1960/70s tech, providing excellent first strike and second strike capability.

Of course actually getting ICBMs on the moon is a whole other endeavor.

Early warning satellites would be a heck of a lot easier to install than the missiles. Basically once someone started building such a plant it would be impossible to hide what you're doing.

You'd never get first strike launching from the Moon, regular ICBMs would be all over you long before the moon IPBMs made the 1 day journey back to Earth. Even with the faster travel speed from only having to accelerate out of the Moon's gravity well, you're talking about a distance of 384,000km vs. 8,000km. Your missiles arrive to a planet that is already a radioactive moonscape.

It doesn't have to be a one day journey. With a 3 ton payload the Atlas B seems to have > 8000km/s delta-v. Getting from moon to earth took Apollo about 4800km/s delta-v, leaving our little Atlas 3200km/s spare fuel. If you use that to accelerate to 3200km/s travel speed you arrive on earth after about 2 minutes (if we ignore the time it takes to accelerate).

I think we can simplify this further. It seems reasonable to assume that any weapon deployed on the surface of the moon would be devolved and dedicated specifically for that purpose, so we can ignore playing theoretical math games :).

It would also be fairly obvious that someone was trying to move several thousand pounds of hardware onto the moon, and launch detection satellites would be even more effective at monitoring the moon. So you've got a first strike, that will be detectable basically immediately, and weapons that now need to travel ~385,000 km and survive even more serious re-entry than the ICBM's based on Earth. Or you've got a second strike capability that cost you billions of rubles/dollars.

Once you look at it like that, its pretty easy to see why the submarine launched weapons were the preferred method for threatening rapid first strike while providing a guaranteed second strike capability.

Can a missile survive reentry at 3200km/s? From https://www.grc.nasa.gov/WWW/BGH/hihyper.html LEO reentry speed is 17500 mph = 28000 km/h = 7.7 km/s. It's 415 times the speed.

I didn't do the math but at that speed you don't need a warhead to destroy a target. Let's try with 1000 kg steel or whatever won't melt down

1/2 mv^2 = 500 * (3200 * 3600)^2 = 345,500,000,000 J

1 J lifts about 100 g mass by 1 m on the surface of Earth. That energy would lift 345,500,000 kg by 100 m.

A two minute travel time is ridiculous. Even light takes more than a second to reach us from the moon.

The lunar orbit->earth delta-v is 4.8km/s. I didn't check your other numbers but they seem to be off by a factor 1000 too.

You are off by at least 3 orders of magnitude.

Besides acceleration at the moon side, wouldn't there need to be deceleration before entering the atmosphere? I'm thinking an IPBM traveling that fast would rip apart in the upper atmosphere and/or explode too high to cause any real damage.

If you can land a ship on the moon, you can land an ICBM on a house in Moscow. It was less about launching from the moon. It was more about getting it to land where you want.

>Also the Soviet Union was winning most of the relevant milestones in space (first satellite, first animal in orbit, first human, first woman, first space walk, etc), and this was a great source of national pride. Beating them had great propaganda value.

I would rather say that the Soviet Union was winning the irrelevant milestones, precisely for the propaganda value. First woman in space means nothing, really - you put a woman on your spaceship, wham, easy win. The moon landings forced the USA to tackle real engineering challenges - rendezvous and docking, piloted spacecraft and piloted orbit changes, functionally useful EVAs, keeping humans alive in space for long periods, etc.

First satellite and first man in space are not irrelevant. They're very challenging engineering problems.

First woman in space is technically easy, but it does say something about the two cultures that the Soviet Union put a woman in space almost immediately, whereas the United States didn't do so for decades.

Oh boy, you underestimate the power of feminism. First woman in space is a lot, especially if you go back to 60th of previous century.

That's the point - it's a propaganda win, not a technical achievement in any way. Not to belittle the symbolic importance of it, but cmon - first dog murdered by being launched in a rocket, first time running two manned missions at the same time, first nap in space - a large proportion of the Soviet "firsts" were just low-complexity stunts.

One of the last major "firsts" was "first organisms to circle the moon" - they barely squeaked this one in a few months before Apollo 8, and they accomplished it by shoving some tortoises into a Soyuz (no food or water required!).

Do you have a source for this claim? A base on the moon is a sitting duck for an incoming missile -- it's easier to figure out how to guide a missile near the moon than to shoot down an incoming high-velocity missile.

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