Gayle King’s still riding high after that nerve-wracking Blue Origin mission -- but she’s bringing it back down to Earth just a bit to clap back at the haters saying the money could be spent elsewhere.

TMZ caught up with Gayle, and funny enough -- she used to be one of the cynics too. But, after getting that firsthand experience, she’s seen how much important stuff actually goes into space exploration ... and now, she’s urging the critics to go see it for themselves at Blue Origin HQ.

Gayle makes it clear the money going into space travel isn’t coming at the expense of what’s happening down here on the ground -- something the cynics, such as Emily Ratajkowski, have spoken out about.

You have to check out the clip -- 'cause Gayle also comes for those brushing off the mission as just a "ride," saying it makes the whole thing sound frivolous … and she’s not having it.

Gayle tells us she’s heard from loads of young girls, women -- and yep, even men -- who were inspired by her journey. So, she’s also worried about how all the hater talk could mess with inspiring future generations.