Saturday, June 05, 2010

Spam, spam, spam, Spam!

Maybe it's because I don't post much to this blog (mostly I'm over at but I've been having real problems with Asian spam, so I've turned on moderation here for all message comments.  It's not like the action is so fast-paced here it will put a cramp on things, and maybe it will at least keep the damned spammers under control.

But if you leave a comment, be aware, it may not show up for a while until I've had a chance to review and clear it.


Friday, June 04, 2010

SpaceX Excels Through Patient Steps to Space

Today's successful first launch of SpaceX's Falcon9 medium booster and prototype Dragon capsule is a vindication of their patient, determined, building-block approach to space flight, one that resembles the original NASA method far more than what NASA has done since the cancellation of the Apollo program.

The Falcon 1 was a test program for everything that followed, an "X-Plane" if you will, but it was also designed as a functional commercial launch vehicle that could take small payloads to orbit. It had its share of failures before it succeeded, but it was designed to. The scale was small enough that failures were economically survivable, which probably wouldn't have been possible with a larger vehicle. It was also complete enough that if money had run out for further development, they still had a launcher to sell. Brilliant.

Upscale the structure of Falcon 1, put nine Merlin motors in the first stage instead of 1, one Merlin with a bigger nozzle in the second, multiply many of its systems, and you have the medium lift Falcon 9 that flew today. The approach of clustering to create a larger booster resembles the very successful Saturn Ib booster used on many Apollo orbital flights, manned and unmanned (including taking astronauts to Skylab, and the Apollo Soyuz mission). The Saturn I clustered and stretched tanks and engines used on previous launch vehicles (the Saturn Ib had eight first-stage engines).

But while the Saturn Ib was a mass of mismatched parts, the Falcon 9 is built more like a Lego toy, from a smaller number of common elements. The first and second stages use different versions of the same engine. The first and second stage use different versions of the same structure, and therefore overlapping tooling to build them, roughly half the work to verify the structural methods and performance.  The Falcon 1 and Falcon 9 share many common parts and systems.

Like the original NASA approach, Space X is designing launch vehicles independently of their mission. Falcon 9 can be used for satellite launches, to loft cargo in its Dragon capsule, and eventually astronauts (or paying passengers) as well. But it isn't limited to those things, or overspecialized in ways that cripple it for other missions (see the Shuttle as a worst-case in this department).

Today's launch isn't the end of the road. It's a mid-point in their master plan. The next Dragon capsule to fly will be fully functional on orbit, able to maneuver under its own power and do everything except dock with the space station. Docking is the next step. At some point, they also need to demonstrate reentry capability, and (if the capsule is to be used for manned launch) an escape rocket system.

But even that isn't the end. Incremental upgrades to Falcon 9 are certainly possible, and Space X eventually plans the Falcon 9 Heavy, a heavy-launch vehicle that straps two Falcon 9 first stages as boosters to the sides of a central Falcon 9.

In fairness, it should be pointed out that the building-block approach may have its limits. The Saturn Ib was a huge success, but the Russian N-1 Moon rocket (challenger to the mighty Saturn V) was a colossal failure. It may not be fair to make comparisons though. SpaceX shouldn't suffer the political snafus and pressures that hamstrung the N-1 program, and the engineering problems are far better understood (as are the tools for predicting and solving them).

Today, Space X has announced that they're in early talks with NASA on the development of a future "super-heavy-lift" vehicle. Would this be a Falcon 9 heavy with four strap-ons, build on some further upscaling of the core vehicle, or would it be the start of a new cycle of development built around larger motors and structures? It will be exciting to find out.