Chair Force Engineer

Thursday, May 10, 2007


Direct Launcher is back in action.

After taking some lumps from NASA's Doug Stanley back in December, the Direct Launcher proposal has been updated. Version 2 is now online at the Direct Launcher website.

The revised proposal was the product of a small but dedicated team, combining the efforts of the original DIRECT team plus TeamVision. The resulting launch vehicle is named "Jupiter" and comes in several variants. Important revisions to Jupiter include:
--The tried-and-true RS-68 (in quantities of two or three) provides the first stage propulsion, instead of a regen-cooled variant that doesn't yet exist. The change is more consistent with the DIRECT philosophy of "Let's use what we have today instead of reinventing the wheel."
--The Earth Departure Stage is defined in greater detail, using two near-term J-2XD engines instead of the definitive J-2X.
--The new architecture allows for the Orion service module to perform the LOI burn instead of the LSAM. This is a more efficient use of system mass than NASA's baseline.
--As more confidence is established after several lunar sorties, DIRECT can evolve into an LOR-LOR architecture instead of EOR-LOR.

The important thing to remember is that DIRECT is the guiding approach/philosophy, while Jupiter is the family of launch vehicles. Noting that this is a family of vehicles is important, as Jupiter can evolve with a stretched first stage and five-segment SRB's once more money is available.

The DIRECT V2 proposal is quite short in comparison with DIRECT V1. It reads more like an addendum to the V1 proposal, rather than a stand-alone document. It's important to remember some of the V1 proposal's key points, like the re-use of shuttle launch pads and facilities, and the problems with Ares I that will prevent it from being safe, simple or soon. While some of DIRECT V1's criticisms of Ares were unfounded, it's still true that the Ares I-Orion stack has extremely thin performance margins, and requires multiple burns of the same engine that will be used for the return from lunar orbit.

At the risk of sounding like a cheerleader, DIRECT V2 is the only way that NASA can achieve its goals of going back to the moon "safe, simple & soon" in the current budgetary climate. It's pleasing to Congress because it preserves shuttle jobs/votes, it closes the manned spaceflight gap after the shuttle retires, and it will probably be cheaper to develop than Ares I.