I watched the movie as a teen. I believe the movie is from 80's. One of the actors is not Jean Claude Van Damme but is similar to him but in less famous movies.
In the future some soldiers were losing a war. So they get on a spaceship and traveled in time back in the past to find a person that wrote a book to prevent him from writing the book which will became like religious book. And they had explosives around their necks, they were 2 guys and a woman. They managed to remove the explosives. And they made it. But only the woman came back to her time in the future and it wasn't the same. It was some beautiful time and I think she was found by some huge unknown for her ship from the new peaceful time and there she met her kid. And she was in a new unknown world but more beautiful world.