Chair Force Engineer

Saturday, January 13, 2007

What doesn't kill us...

...only makes us stronger.

That's my reaction to Doug Stanley's analysis of the Direct Launcher proposal. I'm glad that Dr. Stanley gave his honest assessment of the situation, and I don't believe he's trying to pull a hatchet-job.

As it stands, the "Direct" rocket can't launch the moon mission in two launches. This is because the regeneratively-cooled RS-68 variant doesn't live up to the expectations that Ross Tierney and other "Direct" supporters had for it. At the same time, I don't think that we should give up on Direct. My firm belief is that NASA's budget will not support the development of the Ares I&V boosters. It may not even support the development of a single Ares IV booster (especially in light of the fact that NASA will continue to be funded at FY2006 levels instead of getting a planned increase of ~$500 mil.)

I see as many as five approaches for fixing "Direct."
1) Reduce the size and capabilities of the Orion capsule & lander.
2) Split the mission into three launches instead of two.
3) Use existing SSME's instead of RS-68's, because the shuttles won't be needing them after 2010.
4) See if the Russians can still produce RD-0120's.
5) Shave mass off the SRB's by using filament-wound casings and deleting the parachutes.

I see option 1 as a non-starter. After all, NASA's plan was sold to America as "Apollo on Steroids." If we suddenly took the steroids out, it would be a major letdown to the congress and ultimately the taxpayers who will have to fund it. Still, there are plenty of smart people out there who argue for more austere initial missions and open-cockpit landers.

Using three "Direct" rockets instead of two Ares IV's or one Ares I + one Ares V is not inherently bad. NASA may cringe at the thought of an additional rendezvous in earth orbit, but I see it as an opportunity to decrease the "standing army" costs that are spread over as many launches as can be made in a given year. The cost of adding one or two additional "Direct" launches per year (assuming two lunar missions per year) over the life of NASA's moon efforts might be cheaper than the development and standing army costs associated with the Ares I/V or Ares IV.

How dare we throw out SSME's? Well, I would still argue that the cost of producing and expending SSME's is worth considering in light of development and standing army costs. Besides, at the time of the Shuttle's retirement, there will be several SSME's that are capable of being flown again. The museums might get mad, but the SSME's will be sacrificed for their intended purpose if they are reused for an expendible rocket. That was similar to the plan for Shuttle-C, to use SSME's near the end of their useful lives. Alternatively, a recoverable engine pod could be developed, although that means more development costs and retaining recovery assets that would be used to fish the engine pod out of the ocean.

My favorite option (and the most questionable option) is to get the Russians to start building the RD-0120 again for use on the "Direct" rocket. This was the engine used for the Energia core, and had similar performance to the SSME (think of NASA's expendible SSME or the earlier Space Tramsportation Main Engine.) Of course, "Not Invented Here" comes into play, although the use of Russian engines for the Atlas V has eased those fears to some degree. A more realistic concern is whether the Russians possess the tooling and manufacturing expertise to put this engine back into production. Supposedly the RD-0120 plant is now used for producing consumer goods like baby formula.

The "lighter SRB" option isn't a complete solution for Direct's performance issues, but it's always a smart way of saving money and getting a little more payload to orbit. Most of the issues regarding filament-wound casings for the standard SRB were solved in the 1980's prior to the loss of Challenger. The biggest problem was that the emptied casings weren't as tough as the standard ones when it came to splashing down, and there wasn't a reliable way to determine if there was any delamination between the filaments. The simplest solution is to throw the SRB's away, leave off the mass of the parachutes, and dispense with the mini-Navy that NASA uses to recover the SRB's. Recovery of the boosters has never been better than a break-even proposition anyways.

We shouldn't count out "Direct" yet. An independent analysis of the different options (multiple Atlas launches, variants of Direct, Ares IV, and Ares I + V) should all be examined from the standpoint of total lifecycle costs. The use of multiple Atlas V's is even worse than Direct (from NASA's perspective) in all the regards that NASA has used to disqualify Direct. Still, I consider the use of multiple Atlas V's to represent a real step forward in terms of building a free-market, spacefaring society and an economy of scale.