Bussard Ramjet

This digital image shows a venerable design for an interstellar vehicle. Magnetic fields would collect stray hydrogen atoms and draw them into the funnel in the front. There they would be compressed and used to fuel a fusion reaction to propel the starship at relativistic speeds. The ship would have to be accelerated to a high speed by some other means before the ramjet could even begin to work.

Image copyright by Joe Bergeron.