I'd expected to see a mention of Korean Boeing that was shot down by Soviets, which prompted Reagan to make GPS available for civilians. As in [0]

"President Reagan announced on September 16, 1983, that the Global Positioning System (GPS) would be made available for civilian use, free of charge, once completed in order to avert similar navigational errors in the future."

[0] https://en.wikipedia.org/wiki/Korean_Air_Lines_Flight_007

That's a nice example for a reasonable reaction from politics. Good to know!

I don't know how you can mention the history of GPS, politics, and not include this:

https://en.wikipedia.org/wiki/Korean_Air_Lines_Flight_007

It was one of the biggest reasons why the military-only GPS system eventually became available for civilian use.

Just imagine if GPS was developed today. There would be widespread blaming of programmers involved because "they are writing software for targeting missiles used to kill people".

I’m not sure if those are supposed to be scare quotes or just the regular kind, but just in case: that was exactly the original purpose of it, and not just kill people, but kill hundreds of millions of them. I imagine the only reason it didn’t get protests is because it was relatively obscure.

The military side of GPS was more intended for killing retail rather than wholesale. ICBMs and strategic bombers have always relied more on stellar and inertial navigation since they knew they couldn't rely on GPS in a WWIII scenario.

Nuclear weapons were a major use case. Ballistic missiles wouldn’t use GPS in flight, but they need to know where they were launched from to a high degree of accuracy. That’s easy for ICBMs in silos, but a major problem otherwise. GPS greatly improves the accuracy of SLBMs and mobile ICBMs (which we never actually fielded, but that was the idea).

Do you have a citation for that? SLBMs are launched submerged so I don't see how GPS would work.

Wikipedia discusses it, although its source is pretty weak. The Navy’s TRANSIT system, a predecessor to GPS, had Polaris submarines as a major use case.

I’m not sure just what they do, but there are several possibilities for a submerged launch to use GPS. The sub could surface periodically to take GPS readings and keep the fix up to date with other systems, or it could run an antenna up to the surface, or it could let the missiles acquire their own fix after they breach the surface.

Keep in mind that high accuracy is mostly important for a first strike, when you’re trying to destroy the enemy’s nuclear weapons in hardened targets. A second strike can be much less accurate and still be useful. So the idea that you can’t use GPS because it will be destroyed in the war doesn’t necessarily apply.

At some point the rocket is out of water.

The missile accelerates so quickly that once you factor in the lag time for obtaining an accurate GPS fix without current ephemeris data it would be effectively useless.

I was making a parallel with the outrage over the Google army contract.

And I believe mikeash was pointing out that, indeed, the parallel is an accurate one.

Right. That is, it wouldn’t have been people blowing things out of proportion because of a perceived tie to military applications, but a reasonable response to a system whose major purpose was to facilitate the deaths of millions.