Reusable Rockets

What goes up in the space launch business generally comes back down, at least as far as the launch vehicle is concerned.

At the moment the launchers are expendable, which makes about as much sense as driving your car to an appointment in Sydney and throwing it away. So the boys at Space X, a brash young space transport start up with a new rocket the Falcon, have been planning to get more than one squeeze from the tooth paste tube, so to speak… 🙂

Their first approach was to do the traditional parachute and splash down in the sea, but this isn’t as simple as it seems and after you’ve dropped your high tech space vehicle into salt water it’s not going to be worth much. NASA’s SRB refurbishment program notwithstanding…

So their current plan is to turn their first stage around do a snappy de-orbit burn and then motor home to a spot landing on the tarmac. Absolutely wizard prang as they say, see here for for a video of how they envisage it working.

OK, so I like their style, but a few observations from the cheap seats.

First every pound of fuel you’ve got to carry to land with needs fuel to carry it up. That means either a bigger booster or reduced payload. That’s actually the advantage of parachute return they’re about the lightest recovery option going.

Second, you now have to design your flight vehicle to have structural integrity under a new set of aerodynamic loads. Again potentially more mass, not insurmountable but it does mean less payload or (again) a bigger booster. Unless of course you adopt the pressurised balloon tank system pioneered by Atlas, just a thought. 😉

A potential alternate recovery system would be to use a hatful of fuel to de orbit, then aerobrake in with a ballute or more traditional drogue chute before firing up the main engines for the powered terminal descent phase and landing. In a way that’s exactly how the Soviet Soyuz capsules operate.

From memory there were some studies done during the dying days of Apollo on using a similar approach to recover the Saturn main stage.

Of course the hidden advantage of a reusable booster is that you can actually flight test the damn thing before you loft your commercial payload so selling increased mission reliability is maybe the way in which Space X is intending to recoup their additional costs.

Whatever they elect I wish them the best of luck.

P.S. Love the Muse soundtrack guys…

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