Elon Musk's Grasshooper vehicle has inched a little closer to becoming a viable VTVL (vertical takeoff, vertical landing) rocket, last week completing its highest flight to date.
A video published by SpaceX on YouTube shows the ten-storey-tall jumper reaching 744 metres in altitude (a snip over 2,500 feet) before performing its now-routine rocket powered descent and touchdown.
Along with the divert test conducted in August, in which Grasshopper executed a lateral manoeuvre that took it 100 metres from its launch pad and back, the project is nearing a point where SpaceX will test it in a real-world configuration.
Grasshopper is based on the first stage of a Falcon 9 rocket with a Merlin 1D engine. In nearly* every space-faring craft ever built, the launcher is a throwaway that burns up or drops in the ocean.
SpaceX wants to cut the cost of launches by creating reusable boosters that return to the launchpad. That's because most of the cost of a liftoff is isn't in the fuel (around $200,000 for each flight) but embedded in the use-once-and-discard launchers.
With a fully-developed Grasshopper, the first stage would become reusable, at the cost of some extra fuel and sundry engineering efforts. ®
A reader has taken me to task on the basis that the X15 didn't drop anything into the ocean. Ok, so in nearly every space-faring craft, the booster drops into the ocean. In my defence, the X15 reached near-space and didn't use separate boosters anyhow.