Idea for a high speed "craft"...would this work? Note: since I am not a physicist, I can't be certain how foolish I might sound if the following hypothetical device would not be physically possible (or economically useful, for that matter), but I'm a curious sort of fellow, so I'd appreciate any expert opinion on it, anyway. Imagine one were travelling in some kind of rocket-powered craft (in a vacuum) which had a maximum speed of about 1 mile per second, because the fuel simply cannot burn/expand any faster. But, this craft had a mineature version of itself on board. The mini-craft takes off. Could it reach a speed of 2 miles per second? And, would it be theoretically possible to reach much higher speeds by having a whole 'stack' of craft with progressively smaller versions of themselves, each taking off when the previous reached maximum speed, until eventually reaching near light speed?