While some may say that nothing is impossible, that is a word that has been frequently used by experts to describe SPR Ltd’s EmDrive. To some, EmDrive is crazy, junk science that will never amount to anything; however, its inventor Roger Shawyer has stuck by it resolutely and insists that this novel spacecraft propulsion system works.
EmDrive is a highly efficient propellant-less propulsion system that converts microwave energy into thrust inside a sealed chamber. Such a system would be a complete game changer in spaceflight; it could dramatically cut the cost of satellites and space stations, extend the lives of spacecrafts and drive deep-space missions. But there’s a problem- it violates Newtonian laws of physics, in particular the law of conservation of momentum. Critics have therefore claimed that any thrust generated by prototype systems tested so far must be coming from another source.
Despite supposedly being impossible, the work has sparked genuine interest in some. For example, Chinese scientists have independently and repeatedly proven the theory of EmDrive. Just last year in fact, a Chinese team built their own EmDrive and confirmed that it produced 720 mN of thrust, which would be sufficient for a satellite thruster. This system could be powered by solar electricity, negating the need for a bulky propellant. However, the work was largely ignored and scientists were still far from convinced.
Now, the big boys in the field, NASA, have swooped in and tested the viability of a microwave thruster built by US scientist Guido Fetta. The results are in, and it seems Shawyer may have been right after all.