March 15, 2024

Open Thread 152

It's time once again for our regular open thread. Talk about whatever you want, so long as it isn't culture war.

As a reminder, the New England meetup is coming up in early May. The AirBnB is full, but anyone who wants to come can get a hotel room nearby. Currently signed up to go are:

  • Bean and Lord Nelson
  • Sam Chevre
  • Hunter
  • Ian Argent
  • SoupPirate
  • John Schilling
  • Usea2b
  • smd
  • 2 Friedmans

Also, we have a request for travel funds from someone who would like to attend but can't afford to on their own. If you're willing to donate, send me an email.

Overhauls are Russia's New Nuclear Weapons - A Skeptical Look, Military Procurement - Pricing, Amphibious Warfare Part 5, Letters of Marque Today, and for 2023, my review of the museums at Fort Leonard Wood and Confederate Raiding Part 8.


  1. March 16, 2024Hugh Fisher said...

    A recent YouTube video from Perun: US Navy Procurement Disasters - LCS & DD(X)

  2. March 20, 2024ack-acking said...

    Do you have any thoughts on whether Project Excalibur, aka "Star Wars," aka lasers in space, could have actually worked?

    On one hand, it strikes me as the only system that could, theoretically, stop a full nuclear strike. Everything else suffers from the problem where the interceptor missiles cost just as much as the attacking missiles, while also sometimes missing. The lasers could theoretically blow up many missiles with one shot.

    But then you need the lasers to actually work, and they never quite got that figured out.

    But then again, they had to stop doing actual tests because of the ban on nuclear tests. They did get produce a working X-ray laser, just not one powered by nuclear explosions. Is it actually possible to make a system that would both generate lasers, and not be destroyed by the blast itself? Or was this all just 80s hype and propaganda?

  3. March 21, 2024John Schilling said...

    Project Excalibur was hype and ego - Edward Teller's ego in particular. There was no real chance of its working. The physics were extremely questionable and based on best-case assumptions, the tests were poorly conducted and misreported, and even if the laser part had worked as advertised, there would be no practical way to aim it. You'd need milliradian accuracy from a weapon that cannot be boresighted to its targeting system because it will destroy itself in the process of lasing.

    "Star Wars", was more than just Project Excalibur, and some of the alternative concepts were at least in principle workable. Including some of the lasers, just not the bomb-pumped ones.

  4. March 21, 2024Ack-acking said...

    Which laser systems from SDI are you thinking of? The only other one I know is the airborne mounted chemical lasers. The problem, as I understand it, is that you just need a massive amount of power for a laser to actually destroy a missile, especially with 1980s laser tech.

  5. March 22, 2024Commodore Perry said...

    One of the criticisms of SDI lasers was that reflective paint would be an effective countermeasure. Was that concern ever real? Is is a problem for modern day anti-missile lasers?

  6. March 22, 2024John Schilling said...

    Several different types of laser were considered for the Strategic Defense Initiative, including chemical lasers, excimer lasers, and free-electron lasers. None of these had proponents with the combined reputation and ego of Edward Teller, of course. They did have the advantage of verifiably producing laser light of high intensity and beam quality.

    The best-developed were the chemical lasers, which as you note worked well enough to destroy missiles in tests of the YAL-1 airborne laser. The performance wasn't good enough in that case for a full SDI capability, but there was room for improvement. In particular, the primary mirror on the YAL-1 was limited to ~1.3 meters diameter by aerodynamic concerns; space-based laser proposals typically envisioned 3-5 meter mirrors. All else being equal, the effective range of a laser is proportional to diameter, so that's a pretty big gain for not having to be pushed through the air at 600 mph.

    As for using mirrors to reflect enemy laser beams, basically no. Mirrors are A: imperfect and B: famously breakable; the sorts of mirrors that are robust enough to survive silo launch, solid rocket boost, and aerodynamic flight, are even more imperfect as mirrors. The imperfection means that there will still be significant heating, the fragility means that the heating will further degrade it as a mirror.

    Also, every bug-splat on the missile's exterior as it ascends, is a point of concentrated failure under laser illumination.

  7. March 23, 2024ack-acking said...

    Thanks John Shilling. I didn't know they were doing tests of a ground-based laser bouncing off of space-based mirrors. That seems like a brilliant design, if it could be made to work. You get all the benefits of a laser in space, avoiding most of the atmosphere, while still having a system mounted on the ground with plenty of power and no weight limit.

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