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. They hope to have a prototype done by 2020. Guys this means space tourism could be a legit thing by the time I’m 30.