there will be significant design differences between the ISS Orion and the lunar Orion (including heat shield designs and communications ect...). Designing Orion to service the station seems to only further undercut our moon missions with further delays and design costs.
If one assumes that Orion will fly on a liquid rocket the escape system also be simplified as you no longer are running away from a lit SRB.
This simplified Orion could fly on a Delta(5,4) or an Atlas(521).
If we are going to actually get to the moon we need less of this block 1/2 stuff - everything needs to be lunar capable from the start.
But to get it onto Ares-I for ISS missions, they are simply planning to fly only two of the four propellant tanks inside the SM.It's a quick fix. Easy to accomplish, and safe.
I think the big question should be: "Are we expecting too much of Orion?"While most of us agree that the new system will be more fragile
With regards to your opinion I'm worried about the thrust oscillation problem and the SRB design.
So you are loosing the redunancy of backup tanks and capability if one of the tanks springs a leak.I wonder what all this does to the LOM/LOC numbers...Safer because there are less tanks? Less safe because you don't have backup fuel in a seperate system to save the crew?