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Thanks. I'm just surprised that the cost of damage from seawater to a dumb rocket with a parachute and floats is more than the cost of a smart rocket making a

Thanks. I'm just surprised that the cost of damage from seawater to a dumb rocket with a parachute and floats is more than the cost of a smart rocket making a much more error-prone landing on a tiny ship.

lallysingh 11y ago
After R&D you're just paying for the additional fuel to land safely. The control systems are already there for the other parts of the trip. Also, I assume it's a lot easier to be sure that the rocket's in good shape if you don't have to check the interior for leaks, and whatever chemicals seeped in with the water?
madlag 11y ago
There is no such thing as a dumb rocket : to get down, they are using almost exactly the same stuff they use to get up, weight wise: they use the gimbaled engines, and the nitrogen attitude thrusters. The only additional devices are the grid fins, to control aerodynamically the descent, and the legs. Then you have to write the right software, and it does not weight much more ;-)
- samstave 11y ago
  Is this the first rocket with legs? Seems like every thing else in history has really been a missile. This thing can land, so seems like it's literally the first rocket. Do we have a definition of missile vs rocket?
  - ygra 11y ago
    A missile historically has been anything that was thrown or launched. Nowadays it usually means a self-propelled weapon. A rocket is just something with a rocket engine. Note that missiles do not need to use rocket engines and rockets don't need to carry warheads.
- Retric 11y ago
  That and a little extra fuel. But, as you say probably less weight than you might think. Also, getting dunked in water probably adds quite a bit of new stresses so you would need a stronger rocket shell which is more wight.
CydeWeys 11y ago
> I'm just surprised that the cost of damage from seawater to a dumb rocket with a parachute and floats Maybe it helps to think by analogy. Which is harder, putting a car on a ferry to carry it across a river, or just driving it into the river and fishing it out the other end? Sure, you'll have to replace the engine and the electronics and lots of other stuff (i.e. all the most expensive parts of a car), but if you're only doing it once, it's cheaper to ford that river Oregon-Trail-style than to get yourself a ferry. But if you're doing it many times ... The point is, there's lots of extremely high precision, expensive stuff on a rocket, that don't appreciate being dunked in water in exactly the same way that, say, your computer or car wouldn't. Those engines are incredibly complicated, high performance, and expensive, and they don't have the benefits of economies of scale like other consumer goods that are manufactured in the amounts of millions or billions per year. Each rocket has nine Merlin engines on it; that's an awful lot to essentially have to replace with every launch. The barge is cheaper.
- kpennell 11y ago
  good stuff

lallysingh 11y ago

After R&D you're just paying for the additional fuel to land safely. The control systems are already there for the other parts of the trip. Also, I assume it's a lot easier to be sure that the rocket's in good shape if you don't have to check the interior for leaks, and whatever chemicals seeped in with the water?

madlag 11y ago

There is no such thing as a dumb rocket : to get down, they are using almost exactly the same stuff they use to get up, weight wise: they use the gimbaled engines, and the nitrogen attitude thrusters. The only additional devices are the grid fins, to control aerodynamically the descent, and the legs. Then you have to write the right software, and it does not weight much more ;-)

samstave 11y ago
Is this the first rocket with legs? Seems like every thing else in history has really been a missile. This thing can land, so seems like it's literally the first rocket. Do we have a definition of missile vs rocket?
- ygra 11y ago
  A missile historically has been anything that was thrown or launched. Nowadays it usually means a self-propelled weapon. A rocket is just something with a rocket engine. Note that missiles do not need to use rocket engines and rockets don't need to carry warheads.
Retric 11y ago
That and a little extra fuel. But, as you say probably less weight than you might think. Also, getting dunked in water probably adds quite a bit of new stresses so you would need a stronger rocket shell which is more wight.

CydeWeys 11y ago

> I'm just surprised that the cost of damage from seawater to a dumb rocket with a parachute and floats Maybe it helps to think by analogy. Which is harder, putting a car on a ferry to carry it across a river, or just driving it into the river and fishing it out the other end? Sure, you'll have to replace the engine and the electronics and lots of other stuff (i.e. all the most expensive parts of a car), but if you're only doing it once, it's cheaper to ford that river Oregon-Trail-style than to get yourself a ferry. But if you're doing it many times ... The point is, there's lots of extremely high precision, expensive stuff on a rocket, that don't appreciate being dunked in water in exactly the same way that, say, your computer or car wouldn't. Those engines are incredibly complicated, high performance, and expensive, and they don't have the benefits of economies of scale like other consumer goods that are manufactured in the amounts of millions or billions per year. Each rocket has nine Merlin engines on it; that's an awful lot to essentially have to replace with every launch. The barge is cheaper.

kpennell 11y ago
good stuff