It's probably something NRO related.

The idea of using shuttles to manage or deliver a nuclear deterrent/first strike capability in space was probably considered at some point during its development. If there was one reason to scratch this idea, it would be that launching a nuclear shuttle would have been highly auspicious - and likely treated as the equivalent of an ICBM launch. It's highly unlikely that permanent orbital munitions would be tolerated either.

  > in theory 3 space shuttles could deliver ~90 large warheads or up to 900 smaller warheads.

And even if you could get three shuttles airborne at once, where would you land them? Also, I'm not sure if the Vandenburg launch could land after a single orbit, I think that the Florida launches would land a white sands.

  > Space Shuttles would also have the ability to identify hard to find targets such as mobile ICBM launchers.

Regardless, ICBM's would probably be more efficient way to do it.

However, I am looking at the Wikipedia list of runways in service today. I'm not about to embark on looking at historical data.

The core shuttle design to have rocket engines on the orbiter makes substantially more sense if there was at one point a planned orbital delta-v component. Orbital delta-v really only makes sense for military applications involving satellite capture/servicing or nuclear strike. As all of these can be better done with missiles/robots, there isn't much advantage in a space shuttle except for the case where the payload must be returned from orbit. On a polar trajectory the only use cases where this would make sense are spy satellite returns or weapons missions. Replacing the spy satellite entirely is obviously cheaper than returning and refurbishing it - which leaves a weapons use case which was likely discarded sometime late in the program when it was determined to be logistically infeasible or difficult to pull off.

Yes, most (maybe all) shuttle rollouts were less than the 10000 length of the Machrihanish runway, but that's really cutting it close. SLF Florida is 15000 feet. But I guess if the situation is so bad that the shuttle needs to come down outside the US, it's probably not going to be used again so why not mow the grass at the end of the runway.

Also, the brute force of a nuke doesn't really combine well with subtile operations. Unless you want to 'clandestinely' wipe out a whole city.

You’re entitled to your opinion, but your reasoning is nonsensical.

There's encryption in use the NSA can't crack (SSL). So they..record the entire internet because someday they may be able to crack it. Sounds impossible, but they do. I don't know how many racks in how many data centers it takes, but money is no object.

Create an entire war on drugs to..keep a few percent of the black population from voting. Sounds like evil on a scale that's impossible to believe.

I'm sure your a decent person, which is why you discount how evil evil can get.

*Deployment of X-37B space plane For all its features and achievements, the primary objectives of the X-37B have remained largely classified during its existence, which has now been for more than a decade. The secrecy over the purposes of the space plane has even prompted Russia to say that apart from carrying out surveillance, the space plane could be harboring nuclear warheads.

While the mystery over this remains unresolved...*

https://interestingengineering.com/us-military-orbital-recor...

First, unless the satellite / bomb dispenser happens to be in the right orbit at the right time, you'd have to do some significant maneuvering on orbit. This is expensive in terms of energy/fuel. By the time you put the dispenser over or on the correct path to target, it might not even be faster than a conventional endo- or exo-atmospheric ballistic missile (SRBM/IRBM or ICBM).

Second, long range nuclear strike is one of the USAF's justifications for its silo missile and bomber fleet, particularly the B-2 and just-started-production B-21 Raider (LRS-B). They're going to have some awkward questions to answer if a big part of their signature stealth penetration bomber's mission could have been done by another system all along. Hell, the USAF has been desperately trying to come up with non-nuclear roles for their existing nuclear delivery systems ("Prompt Global Strike", aka "hitting someone in the head with a reentry vehicle full of concrete going 7000 m/s") for years.

Third, it's overly complex for that role. An ICBM warhead dispenser is something that exists; it's called the "bus" on MIRV missiles. If you wanted to put a bomb dispenser in orbit, you don't need a cool spaceplane. You just put a slightly bigger engine (or an extra stage) onto a traditional MIRV bus, so it has the delta-V to get into a stable LEO and sit there until you use or de-orbit it. The Soviets played with this concept extensively during the 1980s, and their "Sarmat" superheavy ICBM is probably capable of it. This was considered pretty destabilizing at the time (since it would avoid north-facing early warning systems) and was banned by treaty. So the US would be opening a can of worms back up that it seemingly tried hard to close in the 1980s, and it's a weirdly complicated way of doing it, vs. just building a superheavy ICBM like Russia did.

A lot of the complexity of a Shuttle / delta-plane design is related to getting back from orbit. A weapons dispenser, whether nuclear or kinetic ("tungsten rods from God") wouldn't need to be recoverable at all. Or if you really insist on that as a requirement, it could use a cheap-and-cheerful Apollo-style splashdown design. Why have it land like a plane? Nuclear weapons are pretty robust. You could splash one into the ocean going pretty fast and still have it be recoverable.

Which leads me to my personal theory: the design only makes sense if the intent is to bring things back. Fragile things. The NASA Shuttle landed like it did, because it had fragile humans on board. But why would a remotely-piloted vehicle need to? Maybe if it's bringing back things from orbit that were never meant to land on Earth in one piece.

*The secrecy over the purposes of the space plane has even prompted Russia to say that apart from carrying out surveillance, the space plane could be harboring nuclear warheads.*