Access to High Earth Orbit about to get much much cheaper.
Cambridge University has made a breakthrough that allows carbon nanotubes to be combined into a weblike structure and wound into a continuous ultra-strong fiber filament. This innovation has been predicted for decades in Science Fiction Literature. Larry Niven used it in much of his "Known Space" series of novels, calling it "Sinclair Filament". Sir Arthur C. Clarke also used a variation of it in his novel "Fountains of Paradise".
No data has been released publically as to the UTS or modulus of elasticity of this fiber as of yet, but it is thought to be strong enough and light enough to allow the fabrication of a space elevator similar to that envisioned by Sir Arthur C. Clarke. NASA, which funded the research, is eager to begin playing with the material.
If this material does in fact have the strength required for this project, then it is reasonable to conclude that the current plans for the Constellation program should be reviewed in light of this in order to ascertain what modifications, if any, are required to allow the vehicles to be used in the construction of the project.