Aerospikes aren't radically new. If you think about it, the Russians have gone half way with their trademark multi-chamber rocket engines since the 1960's as w

Aerospikes aren't radically new. If you think about it, the Russians have gone half way with their trademark multi-chamber rocket engines since the 1960's as well. The difference is that there are more burn chambers and they're arranged around a central plug. I.E: http://www.csulb.edu/colleges/coe/mae/views/projects/rocket/news_2008/aerospike06252008.shtml http://www.csulb.edu/colleges/coe/mae/views/projects/rocket/... The central basis of the aerospike has been around for decades. It's not as old as the traditional bell, but it's not only as old as the X-33. And their problem was a radical overall shape including the fuel tanks, plus a lot of other unproven technology. The engine concept was still sound. How come we don't all fly around in 1960's aircraft designs? Some people do, but not all of us. How about 1960's car designs? Computers? Sure, we use a lot of the same principles, but these are worlds apart for a reason. The aerospike isn't exactly a silver bullet, so you'll still have multiple stages, drop tanks etc... but capacity without burn efficiency doesn't mean much improvement. Pragmatism doesn't mean sticking to something cause it ain't broke. If there is a genuinely better way to do things, then it should be explored.