Chair Force Engineer

Tuesday, May 17, 2011

Give Me Liberty, or Give Me The Shaft!

The idea of using a large solid rocket for the first stage of a human-rated crew launcher presents a lot of technical problems, so I was not surprised when NASA stopped development of the Ares I rocket. Supporters of Project Constellation were saddened at the time, but Ares I surprisingly isn't dead. Its principal contractor, ATK, is keeping "The Shaft" alive as a privately-funded venture (without even the benefit of NASA CCDEV money) called "Liberty." The true believers in Ares I now have a chance to put their money where their mouth is and bring the design to life.

I'm embarassed to say that I've been catching up on a lot of the NewSpace developments just now after several months away from the space industry, so the Liberty launcher took me by surprise. Undoubtedly, some of the Ares I vibration issues still need to be addressed in the form of an upper-stage isolation system, the parachute-mounted dampers, or the active d-strut system. Crew survivability in the event that the first stage explodes (either due to design defects or destruction by range safety) will still be almost nil. But other Ares I problems seem to have a solution in the new Liberty configuration.

One of the longest-lead items in "The Shaft's" schedule was J-2X, an all-new upper stage engine with similar performance to the old Apollo J-2. The teaming of ATK with EADS-Astrium gets around this problem thanks to the Vulcain 2 engine. Originally used on the Ariane 5 first stage, the Vulcain engines have been remarkable engines very similar to the J-2 in terms of performance. They were a natural choice to replace the J-2X; after all, Volvo Aero produced the innovative nozzles for both engines. The remaining challenge is whether the Vulcain engines can be adapted to ignite on the second stage, far away from the required ground support equipment they've relied on during the Ariane days. Presumably Astrium will be replacing Boeing as prime contractor for the Liberty's first stage as well.

My biggest questions about Liberty deal with the infrastructure to support the vehicle. Apparently ATK is going to leverage the shuttle infrastructure as much as possible, using the aging Mobile Launch Pads & Crawlers. Presumably the Liberty would be assembled in the Vehicle Assembly Building and launch from LC-39. The inherent contradiction is that these facilities were never designed for minimizing the amount of labor during the launch processing phase of the mission. If Liberty has any commercial prospects, the facilities may become an achilles heel in the face of strong competition from SpaceX, the Boeing-ULA team & others.

Admittedly, I've never been a big fan of Ares I. Perhaps it's a Challenger-inspired phobia of solid rockets, but Ares I always seemed like it would take too long to develop, cost too much to fly, and pose too much of a safety risk to the astronauts who flew onboard. But ATK now has the chance to prove me wrong. At least they will have to rely on their own money to make it work, instead of keeping "business as usual" going solely at the taxpayers' expense.