I suspect that we would see Taurus re-engined with Merlins before we saw US manufactured AJ-26-62 engines.
Quote from: Danderman on 08/23/2008 08:06 pmI suspect that we would see Taurus re-engined with Merlins before we saw US manufactured AJ-26-62 engines.No, for many reasons1. Spacex isn't going to help a competitor2. Changing engines would be more costly to OSC3. Changing engines is not a one for one option
...but then SpaceX also has an upper stage engine to offer...
Hey, f=ma (and then you die...)
Quote from: antonioe on 08/25/2008 08:02 pmHey, f=ma (and then you die...) I've been using f=dp/dt totally unaware of my impending doom.
The Thrust-augmented Nozzle (TAN) AKA "afterburning rocket" is one of those ideas that look OK on paper, but the practical implementation negates many of its virtues; let me list just three:
Quote from: Danderman on 08/23/2008 08:06 pmI suspect that we would see Taurus re-engined with Merlins before we saw US manufactured AJ-26-62 engines.This indicates a lack of the fundamental understanding of how the rocket stage and the engine are a matched pair. What would seem like small changes in the engine operation end up having huge impacts on the stage. Often resulting in the need to resize the tanks and pressurization system... This in turn impacts nearly every subsystem in the rocket. Essentially you're creating and needign to qualify a new stage.A good example of this is the NK-33's mixture ratio 2.8:1 which is normal for Russian engines, but quite high for the US where most engines run 2.4:1. Or another is the minimum propellant pressures that must be provided to the engine pumps, minimum NPSH or NPSP. These are fundamental engine design characteristics, and the rocket has to make changes to accommodate the "new" engine.
That's the trade... Do a Atlas II to Atlas III like development? Or restart production of an engine built 35 yrs ago in Russia? There's time for Orbital to make that decision, assuming their successful in the first place. But it will start to come to head soon after first flight.
There's time for Orbital to make that decision, assuming their successful in the first place. But it will start to come to head soon after first flight.
Merlin was first test-fired a year after SpaceX was founded. How hard is it to make a new engine? I'm sure if there's a large demand for the Taurus II and they run out of engines, someone could just make a new one. Couldn't cost more than $200 million, half a billion tops. Might be a good idea to have one on the back-burner to use as a bargaining chip with the Russians.