SpaceX looks at Saturn V class

[aero313]

GraphGuy - 29/5/2007  2:51 PM
Ultimately I think that having a single F1 engine would be better than 9 of their current engines, assuming that they can book enough launches to keep the production line going.

There's a reason why EELVs have only one engine on each stage.  Unfortunately the "mass production lowers costs" argument breaks down when you start to total up the integration costs for nine engines - nine times the plumbing joints to leak test, nine times the actuators to check out, nine times the igniters, etc, etc.  Not to mention nine times the potential for problems that require rework (which is never counted in cost estimating).

[jongoff]

aero,

There's a reason why EELVs have only one engine on each stage.  Unfortunately the "mass production lowers costs" argument breaks down when you start to total up the integration costs for nine engines - nine times the plumbing joints to leak test, nine times the actuators to check out, nine times the igniters, etc, etc.  Not to mention nine times the potential for problems that require rework (which is never counted in cost estimating).

As someone working on fielding a multi-engine vehicle, I have to agree that it does add some real complications.  Especially when it is a prototype vehicle with developmental engines.  That said, there are some real benefits to having some engine-out capability--especially for cases like ours where we want the vehicle back afterward.  And there really are some efficiencies of scale to be had with higher production rates...

That said, there's a reason why our plans for our first suborbital vehicle have changed from 8 verniers and 4 fixed mains to 4 verniers and 1 or 2 fixed mains.  :-)

~Jon

[privateer]

simonbp - 28/5/2007  8:23 PM
And, strictly speaking, the Shuttle's SRB does have 200+ flights with one failure that has since been rendered impossible. By anyone's measure, that's a pretty stellar flight record...
Simon

How would you qualify flight record of SSME?