NASA's towering Ares 1-X rocket, a test vehicle for a planned crew launcher to replace the space shuttle, remains on the ground at Kennedy Space Center in Florida after the space agency scrubbed its Tuesday launch attempt. The launch team will try again Wednesday in a four-hour launch window that begins at 8:00 A.M. (Eastern Daylight Time).

Tuesday's attempt was ultimately foiled by uncooperative weather, but not before a stuck cover on a probe at the top of the rocket delayed proceedings, as did a cargo ship that wandered into the danger zone under the flight path.

The launch will test components of the Constellation program, a spaceflight system now in development to replace the shuttle, which is scheduled for retirement next year. In the Constellation system, Ares 1 rockets would deliver astronauts to low-Earth orbit.

But with development years behind schedule, an independent panel convened by the Obama administration recently estimated that manned Constellation flights would not begin before 2017. The panel, chaired by former aerospace executive Norman Augustine, also concluded that under NASA's budgetary constraints the agency may have to choose between continuing to develop Ares 1 and extending the life of the International Space Station beyond 2015.

Photo of Ares 1-X on the launch pad Tuesday: NASA TV