Ordering one of each Delta IV (4,4), (5,6) and (5,8) right now would be the best cover strategy. Together with Heavy they can cover everything that Atlas V does at a not so higher cost. Those actions should have a relatively small incremental cost (wrt an AV431, AV531 and an AV551 that would otherwise use the missions). And I would seriously consider reading an activation plan for finishing as much possible in Decantur and doing full integration testing in the HIF. That should enable 6 to 8 missions per year and assure availability of (4,4) for 2016 and (5,6) and (5,8) for 2017.
Ordering one of each Delta IV (4,4), (5,6) and (5,8) right now would be the best cover strategy. Together with Heavy they can cover everything that Atlas V does at a not so higher cost. Those actions should have a relatively small incremental cost (wrt an AV431, AV531 and an AV551 that would otherwise use the missions). And I would seriously consider reading an activation plan for finishing as much possible in Decantur and doing full integration testing in the HIF. That should enable 6 to 8 missions per year and assure availability of (4,4) for 2016 and (5,6) and (5,8) for 2017.
Sounds like a plan to me.
Ordering one of each Delta IV (4,4), (5,6) and (5,8) right now would be the best cover strategy. Together with Heavy they can cover everything that Atlas V does at a not so higher cost. Those actions should have a relatively small incremental cost (wrt an AV431, AV531 and an AV551 that would otherwise use the missions). And I would seriously consider reading an activation plan for finishing as much possible in Decantur and doing full integration testing in the HIF. That should enable 6 to 8 missions per year and assure availability of (4,4) for 2016 and (5,6) and (5,8) for 2017.
Don't forget the all-important upper stages (likely the most immediate upgrade path) :: common 4m (Centaur) upper stage, two engine Centaur, and ACES (common 5m upper stage).
Ordering one of each Delta IV (4,4), (5,6) and (5,8) right now would be the best cover strategy. Together with Heavy they can cover everything that Atlas V does at a not so higher cost. Those actions should have a relatively small incremental cost (wrt an AV431, AV531 and an AV551 that would otherwise use the missions). And I would seriously consider reading an activation plan for finishing as much possible in Decantur and doing full integration testing in the HIF. That should enable 6 to 8 missions per year and assure availability of (4,4) for 2016 and (5,6) and (5,8) for 2017.
Don't forget the all-important upper stages (likely the most immediate upgrade path) :: common 4m (Centaur) upper stage, two engine Centaur, and ACES (common 5m upper stage).
Common Centaur and ACES have their own timelines and critical path. In particular, can only be done after Common Avionics. Delta IV (4,4) can be done today. The new true Common Core is based on the old (5,4). So is actually reinforced for the 4 boosters. It's just certifying the combo. The (5,6) and (5,8) would require new reinforced cores. Obviously would bring back the problem that a (5,4) mission can't upgrade by simply adding boosters to the (5,6), because the core itself would need mods. And a (5,8) whose payload got delayed can't be easily reassigned to a (5,4) mission. But you'd get coverage for a worse case scenario for relatively little money.
It might happen, that ULA's schedule for Common Centaur is such that they would rather debut Common Centaur on a (4,4) or (5,6), but that would only be a potential synergy. In any case most people might not be worried about the Rd-180 availability at all and rather wait for the word war to pass.
I still believe it would be a cautious plan to execute.
Delta IV (4,4) can be done today. The new true Common Core is based on the old (5,4). So is actually reinforced for the 4 boosters. It's just certifying the combo.
Could a high value payload fly on the maiden (4,4) launch, or would a qualifying flight (with a lower value demonstration payload) be required for certification?
The (5,6) and (5,8) would require new reinforced cores.
Two different core designs for (5,6) and (5,8), or could those two share a core between them? (Essentially, what is the performance penalty for (5,6) if it flies with a core structurally capable of flying in the (5,8) configuration? Does it still offer improvement over (5,4)?)