I watched Solar Crisis [1990]
I was attracted to this film as the plot had similarities to the popular scifi Sunshine released in 2007. In this movie a space mission is trying to prematurely trigger a gigantic solar flare before it can fry the earth. There are elements on board the mission trying to sabotage the whole thing because corporations are assholes to the point of deliberately causing global extermination.
You watch this film and it kind of has the earmarks of a low budget movie, but it has a very surprising cast. Charlton Heston. Jack Palance. And Peter Boyle. Tim Matheson (Animal House) is the captain in charge of the mission.
Another surprising feature is the outer space shots look like something that belongs in a bigger blockbuster movie. Also I thought the plot was a little more believable than Sunshine's, where they make a bomb big enough to prematurely trigger a solar flare rather than Sunshine's plot to restart the whole darn sun.
The story goes back and forth from earth to space as Tim Matheson's son has escaped from a military school to try to see his dad before he leaves on what most people think is a suicide mission. This leads on an adventure through a nomadic post apocalyptic looking earth. The story on the spaceship is peppered with suspense of people dealing with sabotage, killing off characters almost like a slasher film. I think there's elements here that may have inspired the movie Sunshine, which has much slicker production and effects but kind of a stumbling plotline.
Over all I say it's worth a watch. Good film.