We caught up with the "Reading Rainbow" host in Los Angeles Thursday, and LeVar explained space exploration is inherently risky ... and every potential problem can't be anticipated, and things often don't go according to plan.

The astronauts are now stuck on the International Space Station until 2025 after technical issues shut down their return flight.

As LeVar put it ... there is no way to create contingency plans for every possible outcome, especially when dealing with space exploration.

While the U.S. may have resources like the Coast Guard to help those stuck at sea, the cosmos is a totally different ballgame ... with LeVar reminding us that space is a vacuum.

LB also made a point to applaud Suni and Butch, saying they put their lives in danger in the name of science. He added ... "The research they do up there actually contributes to life being better here on Earth. So, I'm very grateful to NASA and its mission."

Suni's own mother told us she isn't losing sleep over her daughter's situation ... noting SW is well aware of what could happen every time she goes to space.

Suni and Butch are expected to return to Earth in February 2025, when they hitch a ride back with SpaceX. They originally flew the Boeing Starliner spacecraft to the International Space Station for a week-long mission ... but the Starliner experienced issues during their flight, and NASA decided not to risk their return on the craft.