70's young adult book: high school kids kidnapped on a spaceship which they find out caused the extinction of dinosaurs

This book was in a library in the 1970’s.

It was about a group of high school kids who are kidnapped while on a field trip. They are taken to a spaceship that was last here during the dinosaurs and the habitat has them in it. The ship is run by a computer and the last species studied were a starfish-like species.

The kids find out that there is an evil program that causes the ship to shoot flames at the planet as it leaves, destroying most of the planet. They must find it before it destroys the Earth like it did 65 million years ago.