This was a common idea in science fiction circa 1945-1965; Heinlein especially was convinced that nukes based in space would trump any other strategic weapons system. Yet obviously that didn’t happen so there must have been something basically wrong with the concept. Where did the analysis of the prognosticators go wrong? About the only thing I can think of that the science fiction writers were thinking of rockets as “space ships” whereas the rockets that actually came to pass were torpedoes, one-shot artillery. Yet the V-2 itself should have made it obvious that in principle you could mount an atomic warhead on some sort of super- V2. So why the fixation on missile bases in high orbit or on the Moon?
As I understand it the issue is that first, they’d be hugely destabilizing and likely to spark a nuclear war. They’d allow someone to launch a nuclear attack with almost no warning, leading everyone to operate on a hair-trigger with their nuclear arsenal.
The other issue is that anything in space is highly vulnerable; someone - possible not even a nuclear power - could wipe out your space based nuclear arsenal with a small shrapnel bomb or two kicking off a Kessler Syndrome event. Which results in the loss of both all those weapons for a comparative pittance on the part of the attacker, and loss of access to orbit for everyone for an indeterminate period.
This is why the Outer Space Treaty forbade them, and more importantly why that part of the treaty was followed.
I agree. The central issue is that while nuclear powers would like to have a system that lets them launch a pre-emptive attack, they don’t want other nuclear powers to have such a system that could be used to launch a pre-emptive attack against them. And in the real world, any system that one power can build will be duplicated by other powers.
So the nuclear powers had to decide between having a world where every nuclear power could launch a nuclear attack from space and a world here no nuclear power could launch a nuclear attack from space. And they all agreed they preferred the former.
Were Heinlein et al presuming that there would be a single world power with a nuclear monopoly maintaining the space-based nukes as a deterrent?
No one actually wants a nuclear war. They want their own nuclear deterrent to be credible enough that no one attacks them with nuclear weapons, and failing that, that their nuclear arsenal is sufficiently survivable to strike the other side because you don’t want your remaining population to live under the thumb of the (undamaged) side that just crushed your civilization. But the former is obviously far preferable.
And so both sides in the cold war understood that weapon systems that incentivized a first strike by being undetectable, reducing warning time, prevented counter-attack, etc. were more likely to lead to a nuclear war. Both because it made a first strike by one side more effective, and therefore perhaps pardoxically sort of necessitated a first strike by the other side in order not to be the victim of this enhanced effectiveness first strike.
Space launched weapons could quietly fall to Earth without necessarily being detected, without a long travel time for detection/warning/reaction, and often from unexpected angles. This would be extremely destabilizing as each side would have to be on the lightest hair trigger for the first sign of an attack to launch their counter-attack, which is simply not practical to do over years or decades. Realistically, if one side started deploying space weapons, the other side would have an extreme incentive to attack before they were up there and operational because of how powerful space launched nuclear weapons are.
Both sides recognized that certain weapon systems (both offensive and defensive) heavily incentivized a first strike, which made nuclear war far more likely, and that it was in both of their interests to ban such weapons. That’s the reason we had the ABM treaty, the MRBM treaty, and the outer space treaty of 1967.
Basically, the first goal of every country is don’t get nuked, and therefore they were willing to ban destabilizing weapons even if they seemingly gave them an edge in active nuclear conflict.
As a practical matter, getting that much mass up into orbit is rather difficult and expensive and severely limits your ability to perform routine maintenance. ICBMs and SLBMs are still expensive but less so and also much easier to build and maintain without much loss of functionality.
The assumption made by a lot of SF writers was that the cost of lifting things into orbit per pound would continue to drop to the point they were essentially like shipping things by train or airplane or cargo ship. That never really came to pass. Even now, it does not appear cost effective. Private space companies rely heavily on government subsidies.
I don’t think expense was a primary consideration. Maybe a side benefit, but I don’t know how much it fit in the calculus early in the cold war where both sides were willing to throw plenty of money at coming out ahead. Either side would spend a lot more money chasing smaller edges over the other than space weapons would provide.
That’s one big point. Also, afaik no one in science fiction anticipated the submarine launched ballistic missile, which fulfilled the role of a hard-to-preemptively attack retaliatory force.
They’re science fiction authors who didn’t really do any technical or strategic analysis. That’s where it went wrong.
The better question is, how could it go right? What actual advantages would space-based nukes pose, and would they offset any disadvantages?
The advantage is as SenorBeef observed upthread, which is that these weapons could come from unexpected angles. That’s significant since both the US & USSR had most of their radar coverage over the North Pole. It’s a big enough threat that any side might have gone to war if the other side detected that such a project were close to deployment. This is why FOBS was limited by treaty.
Then there are the practicalities of such systems. They have to remain in orbit. They’re undefended. It’s impossible to conceal any maintenance or repositioning. An adversary could easily position systems close enough to neutralize them in an emergency. Or hell, even just steal the damn things.
Then there’s the fact that these systems aren’t bombers, the warheads can’t just quickly be dropped from orbit. They have to de-orbit, meaning a long and conspicuous burn and a very obvious re-entry trajectory.
Maybe in the future there will be some tactical or strategic situation that will change the calculus in favor of space nukes, but in the current threat environment they’re of little if any practical advantage. Most advantages of space nukes could be achieved by a terrestrial-based FOBS
The problem with science fiction predictions in that era is that they were made in support of dramatic plots rather than real world difficulties. At the same time they were predicting nuclear missiles in space they were predicting space cowboys mining the asteroids, rockets making regular trips between planets and even star systems, humanoid robots taking over jobs, cities under the sea, and city-sized computers. Everything was big and easy and powered by atomic energy, and worked fine the first time without, say, an atomic rocket full of atomic bombs blowing up on the launchpad.
On top of that, the past they were extrapolating from was a decade-long Depression followed by the entire country coming together socially and technologically to win a world war that barely touched the mainland. Their egos were stuffed to bursting by the chance that rockets and atomics played a part late in that war. They were full of both optimism and paranoia and understood nothing about a different future. They were the same people pushing SDI (Star Wars) under Reagan.
They did make the future sound fascinating, fascinatingly close, and fascinatingly possible. But they weren’t prophets.
For The Moon, this was kind of an extreme version of nuclear missile subs. A second-strike capability, that would be mostly safe from anyone trying to take it out with a preemptive strike. That’s assuming you have a Moon base and the other guys don’t, but at the time, RAH and others like him assumed that the Western powers, and the USA in particular, would beat the Soviets to The Moon, and deny them the opportunity to set up such a base.
In at least a couple of his stories, yes, this was a factor. But those were usually cautionary tales, where he was trying to tell people that this was the only way to avoid a World War with nukes. I don’t think he thought such a thing would arise organically, but maybe the US could impose such a peace, if they acted quickly and effectively.
Exactly where it seems to me the concept falls apart.
I thought one of the practical reasons for not doing this, aside from the international legal framework, was that the risk of a nuke exploding while transiting to orbit was too high - a nuclear explosion high in the atmosphere would be orders of magnitude worse, likely for the sponsoring country, than one that happens at ground level or in the lower atmosphere. The dangerous fallout would spread around the globe. Exhibit A: the Challenger disaster.
I don’t see the difference between lofting to orbit and lofting sub-orbitally but extra-atmospherically, like most ICBMs must.
And in any event implosion-based nuclear weapons are inherently failsafe: you don’t get a nuclear explosion unless everything goes according to plan.
The trajectories are different, and the FOBS can potentially obscure the target location and be harder to detect with some early-warning systems:
Though of course space-based early warning and detection systems now provide global coverage.
One thing Heinlein mentions more than once in his writings is the supposed advantage of being higher in the Earth’s gravity well:
Men on the surface of the planet are as helpless against men in spaceships as a man would be trying to conduct a rock-throwing fight from the bottom of a well. The man at the top of the well has gravity working for him
But of course as mentioned upthread warheads in orbit don’t drop down on their target like rocks; they have to deorbit and follow a reentry trajectory which is far from instantaneous. And lastly there’s the fact that unless you had a huge constellation like Starlink of nukes that afforded multiple targeting options, the nukes would spend most of their time out of range of their intended targets; and even then you’d really need maneuverable reentry vehicles with significant cross range away from their initial trajectory.
That’s the same kind of nonsense that almost destroyed planet Omicron IV.
I know there’s a difference in trajectory.
I don’t know the significance of that difference in the context of spontaneous detonation while being lofted in either case, which was @snowthx’s concern.
If spontaneous detonation is somehow a risk in an orbital trajectory, why isn’t it one in a suborbital ballistic trajectory?
In Space Cadet, Matt mentions that orbital nukes are placed into circumpolar orbits, so RAH was thinking very much along the lines of a Starlink-like constellation of nukes. Matt also mentions two of them by name, I-2 and H-1, from which I would say that in-universe, there are at least 18 bombs in orbit, and likely many more.
Heinlein’s comparison of fighting from orbit to fighting from the top of a well is true tactically, such as it is, but ignores the fact that when you’re at the bottom of the well, you usually want to be at the top; but when you’re in orbit, you want to be able to protect things planetside, and you’ll need those things to sustain you in orbit.