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Old 09-11-2017, 05:11 PM
luke strawwalker's Avatar
luke strawwalker luke strawwalker is offline
Join Date: Dec 2007
Location: Needville and Shiner, TX
Posts: 5,822

Originally Posted by tbzep
They want multiple launch vehicles for a couple of reasons.

1. Competition drives the cost down a little.

2. Redundancy. If one launch vehicle gets grounded, the other can be used in its place. I haven't kept up and don't know if it has been replaced yet, but the Atlas V was using an NPO Energomash RD-180 main engine from Russia. That supply could be cut off at any time.


Not replaced YET, but Bezos is developing the BE-4 methane/LOX engine to replace the Russian RD-180's...

I'm not sure they'll incorporate it into the existing design of the Atlas V... the methane/LOX propellant combination would have somewhat different tank volume requirements from the present LOX/RP-1 combination used with the RD-180's.

I think (last I read) the present plan is to basically fly out the Atlas V's and when the BE-4 is ready, come out with a larger Atlas V replacement designed around the BE-4's, for methane and LOX. Basically it's a re-engined version of the Atlas V Phase II proposals that would have enlarged Atlas V by using the larger Delta IV diameter tanks feeding a pair (4 chambers) of RD-180's... Part of that plan is to develop the ACES upper stage as a larger, more capable replacement for the current Centaur upper stage (IIRC).

Later! OL J R : )
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