The Tesla chief aired out his frustration on Twitter Saturday over a decision to potentially yank Starlink access out of Eastern Europe, apparently because it's too damn expensive ... and costing him and his company, SpaceX, a fortune to keep operating free of charge.

CNN says SpaceX honchos recently wrote D.C. to tell them they'd soon ask the Pentagon to start picking up the tab on Starlink as it pertains to Ukraine -- this after already burning through $80 million on their own dime ... with a projection of $100 mil by December.

Despite this report, EM himself is doing an about-face some 48 hours later. Now, he's saying 'screw it' ... we'll take the L and keep up the handouts, even if it puts us in the red.

He tweeted, "The hell with it … even though Starlink is still losing money & other companies are getting billions of taxpayer $, we’ll just keep funding Ukraine govt for free." In response to someone saying no good deed goes unpunished, he said good deeds should still be done.

It's unclear if Elon's being sarcastic here, but on its face -- it sounds like he and SpaceX are gonna bite the bullet on this and keep their satellites afloat as the war with Russia rages on. That's surprising, because lately ... Elon has been accused of being a Putin sympathizer.

A few weeks ago, he offered a would-be solution to the conflict ... and there were some concessions he suggested for Russia, which a lot of people weren't happy about -- including Volodymyr Zelensky, who fired back at Elon publicly for seemingly changing his tune.

The president posed his own poll, simply asking ... "Which @elonmusk do you like more?" The options being ... "One who supports Ukraine" and "One who supports Russia." The overwhelming favorite was the former.