posted 05-27-2009 09:09 AM            

My bona fides as the Retro-Bring-Back-The-Saturns-Guy are well established, so here is a thought experiment for the armchair rocket scientists out there who know how to crunch the numbers on this modest proposal.

I suggest we switch to the Saturn S-IB stage for Orion, only making the new version a mono-tank instead of the nine separate tanks of the original. A common bulkhead fuel and LOX tank would save literally tons off the original first stage weight. Then use the Ares second stage as currently planned.

So, how much payload would a mono-tank Saturn 1B with the Ares upper stage be able to place in LEO?

I believe the largest payload a Saturn 1B lofted was ASTP -- 37,000 pounds into orbit (CSM + docking module).

The Orion CSM weight is currently slated for 45,000 pounds -- that's only 8,000 pounds more than the ASTP payload.

So, how much could a mono-tank Saturn 1B place in orbit? Would the tank streamlining increase the payload capacity by that much?

If not, how much of a stretch of the first stage tanks be required to raise the payload capacty to, say, 50,000 pounds (I'll spot Orion 5,000 pounds for growth weight over the current design)?

This solution would bring back the 8 H-1 engine cluster and thrust structure that would be bolted on to the tankage and there you'd have it -- a first stage for Ares that did not rely on the inelegant use of that hideous SRB.