To ensure the safety of America's 730 million annual air travelers, all new jet engines must undergo arduous FAA safety testing—including a grueling series of static ground tests subjecting them to everything from gale force winds to simulated bird strikes. But how does one reproduce the identical test conditions needed for accurate performance measurements? You use a 32-foot wide wind baffle, of course.
If this works it will change the world, its the SABRE engine in development by Reaction Engines Ltd. It will use oxygen from the atmosphere as the oxidizer and then switch to on board liquid oxygen reserves to make the final push to space. This right here is the next stepping stone to bringing down the cost of getting people and materials into space.