Maybe not as dramatic as we would all like, but it would be nice to see some work put into trying to revive the idea of the air-augmented rocket. Apparently the

Maybe not as dramatic as we would all like, but it would be nice to see some work put into trying to revive the idea of the air-augmented rocket. Apparently the Russians worked on the idea in the 1960's[1]. But the PR-90 look like its as far as they got with the idea[2]. But maybe there won't be one dramatic change that makes rocket travel cheaper. Maybe we keep iterating on rocket and rocket engine designs and eventually looking back it seems revolutionary. As composites get better and better more and more of rockets will be made from composites instead of the current material of choice, lithium aluminum alloy. Plus the increased use of oxygen rich combustion[3] with it's improved efficiency. Also it looks like Ch4/LOX might be more common in the future[4][5][6], which is good because Ch4/LOX has a higher ISP then RP-1 and also is significantly more dense then H2 propellant. There's also so called "slush" or "super chilled" propellants[7], Spacex has even been using it for awhile[8]. So maybe the future will be extremely light, reusable, oxygen rich, staged combustion, methane burning rockets with super chilled propellants? [1]: http://www.astronautix.com/g/gnom.html http://www.astronautix.com/g/gnom.html [2]: http://www.astronautix.com/p/pr-90.html http://www.astronautix.com/p/pr-90.html [3]: http://www.americaspace.com/2015/05/29/new-oxygen-preburner-firings-a-major-step-toward-rekindling-u-s-hydrocarbon-rocket-engine-leadership/ http://www.americaspace.com/2015/05/29/new-oxygen-preburner-... [4]: https://spaceflightnow.com/2017/10/20/worlds-largest-methane-fueled-rocket-engine-test-fired-by-blue-origin/ https://spaceflightnow.com/2017/10/20/worlds-largest-methane... [5]: https://en.wikipedia.org/wiki/Raptor_(rocket_engine_family) https://en.wikipedia.org/wiki/Raptor_(rocket_engine_family) [6]: http://www.russianspaceweb.com/soyuz5-lv-ptk.html http://www.russianspaceweb.com/soyuz5-lv-ptk.html [7]: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19790004067.pdf https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/197900... [8]: http://www.businessinsider.com/spacex-deep-cryogenic-cryo-liquid-oxygen-lox-rocket-fuel-2017-1 http://www.businessinsider.com/spacex-deep-cryogenic-cryo-li...