The DIRECT Route?
Government programs tend to grow in weight, size and complexity. The Space Shuttle began with the dream of a reusable Spaceship launched on a winged booster. Budget cuts eliminated the flyback booster, replaced by Solid Rocket Boosters (see Challenger) and a foam-covered external tank (see Columbia). To fit all customers the payload diameter was increased to 5 meters. Heavy drag-inducing delta wings were added to give crossrange capability, which has never been used. High wing-loading led to the TPS tiles, which are a maintenance and safety nightmare (see Columbia again). The dream of airliner-like service led to an expensive and ungainly system.
The Space Station was conceived as a stepping stone to other worlds. The US decided to save money by assigning major components to Russia. That caused delays in getting the Russian modules ready, and forced ISS into a high-inclination orbit serving Kazakhstan launch sites. The Space Station enjoyed the nice view of New Zealand we saw yesterday, but is useless as a stop for the Moon or Mars.
The Vision for the Moon and Beyond called for new boosters using existing technology. Constellation conceived of a Ares I with an SRB as the first stage and a J-2 powered second stage. A larger Ares V would have 2 SRB's attached to a center stage derived from the Shuttle External Tank. Studies then showed that 4-segment SRB's would not suffice, we would need 5 segments for Ares I and possibly 6 segments for Ares V. Building longer SRB's means a long testing process. The long skinny Ares I has vibration issues, as the rocket acts like a giant organ pipe. This may require heavy isolation machinery in the spacecraft.
Even with lengthened SRB's doubts exist whether Ares I could carry a loaded Orion, leading to a drastic effort to save weight. Capability to land on solid ground may be sacrificed for more water landings, requiring another Navy task force each time. The Essex-class aircraft carriers that recovered Apollo don't exist anymore, so a Wasp or Nimitz-class carrier might have to be diverted from the battle group's normal duties. Has anyone from the US Navy brought this up? Hello?
Ares I could not reach orbit without its J-2X powered second stage. The new engine would be an expensive and time-consuming project. Ares V now increases diameter of the External Tank, requiring new tooling. A sixth engine may be needed. The booster would be so heavy that it would exceed limits of the crawlerway leading to pads 39A and 39B. The pads themselves would have to be rebuilt to accommodate a wider vehicle, the VAB would have to be reconfigured...and so on.
The five-year gap between Shuttle and Ares I would mean thousands of NASA and contractor job losses. As happened in the 1970's, talented people would become unemployed and their expertise lost forever. Ares V would be a very expensive project that would be easy for a future administration to cut. This would leave the US where it started, stuck in Low Earth Orbit.
Presently NASA is determined to develop Ares I and V. In April 2009 an unmanned demonstration of Ares I-X is planned. This test will use 4-segment boosters, a dummy second stage and Orion that will not reach orbit. While it will be spectacular to watch, the test will be far from the vehicle that would carry humans. No doubt with enough time and money the engineering issues could be patched. The Ares I and V designs are capable of reaching the Moon, with work.
Any NASA employee would support Constellation and do whatever possible to make it work. However, a few have quietly been developing an alternative. Last month this writer was in the room for their presentation at ISDC. Yesterday the DIRECT plan reached the front page of the local Orlando Sentinel.
NASA remains silent on a rocket that could rescue the Cape.
"Indeed, an unfinished internal NASA study -- shut down and disowned by the agency last fall -- showed Direct 2.0 would outperform Ares, which the agency is designing for its Constellation program to return astronauts to the moon. The initial results showed Direct 2.0 was superior in cost, overall performance and work-force retention -- a big issue for Florida."
DIRECT 2.0 (website) would make maximum use of common hardware. Jupiter-120 would use 2 standard Shuttle SRB's, around a core built from the Shuttle ET with two currently available RS-68 engines. The crewed spacecraft would match the cargo ability of Shuttle. Jupiter-120 could easily lift Orion into orbit with payload to spare.
The larger Jupiter-232 would add a third RS-68 and an upper stage powered by a J-2 engine, to carry cargoes to the Moon and Beyond. Possibly it could be upgraded to carry payloads up to 140 tons. With a similiar footprint to Shuttle, these new boosters would use NASA's existing launch infrastructure. DIRECT backers claim the system would carry humans to the Moon by 2017, two years sooner than Ares.
Given the challenges to reaching the Moon, DIRECT 2.0 deserves official consideration. A new adminsitration will certainly reassess NASA's progress. In the 1960's a few brave engineers proposed Lunar Orbit Rendezvous, which got the US to the Moon in time to meet Kennedy's goal. Presently NASA engineers are working on DIRECT in their spare time without knowledge of their bosses. There may be time to change direction, and possibly get us to the Moon sooner.