All SpaceX did was building a normal rocket that can land again.<p>Which, as it turned out, was anything but trivial and took 14 years. Their main competitors – ULA and Arianespace – already announced they won&#x27;t be able to manage similar capabilities this decade; and their plans for the next decade are still not as sophisticated as SpaceX&#x27;s approach (they only want to recover the engines and build a wholly new stage around them).<p>Skylon is a massively more ambitious undertaking compared to that – if it works, it&#x27;ll be the first practical SSTO, the first horizontal takeoff spaceplane, the first vehicle to use multi-mode engines, the first practical space plane to use a novel heat shield technology, …<p>That&#x27;s an awful lot of challenges to tackle. <i>If</i> it turns out to work, and <i>if</i> it then turns out to be as re-usable as hoped (something that did never panned out for the Shuttle, and which SpaceX will only learn over the next years for their Falcon), <i>then</i> it could beat SpaceX… in a decade or two.