This is a fascinating idea of how to lob a payload into space with water. Ok, not quite the water rockets you bought when you were a kid (or built as an adult), this uses the vacuum created by burning oxygen and hydrogen to force a column of water into a pocket of hydrogen gas that launches the rocket ( SCRAM jet) into low orbit. The payload needs to be pretty strong, the gee forces are going to be quite extreme. Also, as it needs water to work it can be lashed to a boat and towed to a launch site near the equator and if something goes wrong stuff won’t fall on the neighbors. If this system proves practical it may become the preferred way of lifting tough payloads to a waiting space station.