With the cancellation of Ares1-Y, it looks to be at least
six or eight years before Ares could see a manned flight.
Does it make sense to pursue two different paths to replacing
the shuttle?

I believe that the lack of support for another moon-shot, combined
with the glaring need for lower cost to orbit means this
program is the one that now makes sense.


U.S. Air Force Aims to Launch Space Plane Next Year

"As a reusable space plane, the intent of the craft is to
serve as a testbed for dozens of technologies in airframe,
propulsion and operation, and other items in the hopes
of making space transportation and operations significantly
more affordable. "
http://www.space.com/news/090602-x-37b-space-plane.html


s


Executive Summary
NASA'S SPACE SOLAR POWER EXPLORATORY RESEARCH
AND TECHNOLOGY (SERT) PROGRAM
http://www.nap.edu/openbook.php?record_id=10202&page=1