NavList:

Paul Dolkas, you wrote:
"But guys, get serious. There’s no reason, in this day and age, for resorting to pencil & paper arithmetic, when there are calculators and cell phone apps that do the same thing. Just because the GPS satellites could be disabled doesn’t mean that the CN calculators go belly up at the same time. We are talking about two independent technologies. I applaud the Navy for re-instating CN. But this is the 21st century for God’s sakes. Let’s stop pretending we are back in the days of wooden ships and sails."

Yes, exactly. I'm teaching my "Modern Celestial Navigation" class this weekend, and it is not traditional late 20th century celestial navigation with tables and forms and plotting (I do teach that in a class I call "Intermediate Celestial" because there's demand for it). The key to all of this is to recognize that there are different kinds of failure modes, and they do not all happen at once. We are not immediately thrown back in time fifty years. The best backup to a GPS system is an alternative GPS system. The best backup to the GPS satellite network is the other guy's satellite network. And so on...

Frank Reed

PS: Then again, some people do worry about what would happen to a vessel thrown back in time (and you'll note one of the first comments in the thread points out that they would be lost without their GPS!). And let's not forget the immortal words of the Commander of the nuclear aircraft carrier USS Nimitz on December 6, 1941: "Splash the zeros... I say again... splash the zeros!" That's from a gung ho 103-minute long commercial for the US Navy from 1980 called The Final Countdown (it wasn't really a commercial... it was a feature film... but it sure looks an awful lot like a commercial at times). Ha. There. I did it... I mentioned a time travel movie in context on Back to the Future day!

File: