[hugh3]

One interesting thing I read Elon Musk saying the other day is that it's definitely not fuel -- the cost of fuelling a Falcon 9 is actually only about the same as the cost of fuelling a Boeing 747.

The problem is that the cost of building a Falcon 9 is still similar to the cost of building a 747, and you throw it away after one flight. So if you could recover and re-use the booster rocket then you'd be looking at a serious cost reduction.

[Tuna-Fish]

> So if you could recover and re-use the booster rocket then you'd be looking at a serious cost reduction.

This was the logic behind the space shuttle. But unfortunately, they have to survive to high stresses that inspecting and repairing them between launches costs more than building a simpler disposable launch vehicles.

I honestly believe that as long as we will be using rockets, the best cost savings will not come from reuse, but from increasing the launch volumes to the point where launch vehicles stop being hand-built boutique items and start being mass-produced commodities.

This announcement gives me hope that this might happen during my lifetime.

[InclinedPlane]

The Shuttle is an excellent example of how an initially good idea (reusable launch vehicles) can become twisted and perverted by excessive compromises and congressional meddling. The Shuttle as it was built was actually a step backward from previous generations. Not only was it not properly reusable (it was at best refurbishable and partially reusable), it's unusual characteristics caused it to require a huge standing army of engineers to keep the program going, regardless of flight rate. As the true limits to the flight-rate of the Shuttle came to light it became obvious that no matter what the Shuttle system was capable of it wasn't capable of lowering launch costs over conventional expendable boosters.

It's a good case study in the downfalls of a waterfall type process and of committing too early to a system before it's true character is known.

[hugh3]

I honestly believe that as long as we will be using rockets, the best cost savings will not come from reuse, but from increasing the launch volumes to the point where launch vehicles stop being hand-built boutique items and start being mass-produced commodities.

I'm not sure that economies of scale can get you that far when you're talking something as complicated as a rocket. How many jet engines does Rolls Royce make every year? Rolls-Royce and GE make many hundreds (thousands?) of jet engines per year, but they still cost a crapload of money each.

You might be right, maybe fully-recoverable rockets aren't possible. On the other hand, being personally unqualified to judge, if I've got some random piscinymous internet commenter telling me that it's not possible on one hand, and Elon Musk telling me that it is possible on the other, I'm more inclined to believe the dude who owns a rocket company.

[TheEzEzz]

Hm, if fuel is so cheap then why not bring enough fuel with you to decelerate before de-orbiting? Then you don't have to worry about reentry heat.

[jbri]

Because if you want to take fuel with you, that's a lot of extra mass you have to lift. Which requires bigger engines and even more fuel.

[TheEzEzz]

53 metric tons worth of fuel?

The fuel requirements to decelerate are much lower than the requirements to reach orbit, for multiple reasons. You aren't fighting against gravity, your weight is greatly reduced (having burnt the fuel to get to orbit), and you also don't need to fully decelerate, only decelerate sufficiently to avoid burn-up upon reentry.

The original comment said that fuel was very cheap, and the primary expense was constructing the launch vehicle. Suppose it required five times as much fuel to be able to launch a rocket with sufficient additional fuel to be able to decelerate out of orbit. Wouldn't this still be much more economical if it meant the ability to easily reuse the launch vehicle after reentry?