The first flight of NASA's Ares 1 launcher, originally scheduled for last April, then rescheduled for next month, will now have a planned launch probably sometime in October. Engineers are still working some technical problems, including a vibration during powered flight that tests on the ground have uncovered.
Ares 1 is set to deliver astronauts to low Earth orbit during the Constellation program. Of course, that assumes there will be a Constellation program, and that Ares will be part of it. Other launchers have been proposed by credible people both outside and inside NASA. The Obama administration has not yet fully embraced any manned spaceflight strategy, choosing to wait for the views of Norm Augustine and his committee.
Encountering problems in the development stage of any complex technology program is to be expected. Still, had Ares 1-X successfully performed in April, NASA, and Constellation, would be in much stronger positions today.