Liftoff of the Ares I-X rocket — the first step in the space agency's tentative back-to-the-moon program — was reset for Wednesday.

Besides poor weather, launch controllers had to deal with an odd assortment of technical trouble, everything from a snagged cover for the rocket's tiptop probe to a cargo ship that strayed into an ocean danger zone under the flight path.

Launch director Ed Mango and his team came within two minutes and 39 seconds of sending the rocket on its short test flight. But a big cloud moved over the pad, and the flip-flopping weather was just too much to overcome for the remainder of the four-hour launch window.

Mango finally halted the countdown for good and ordered everyone back Wednesday morning for another try. The weather was expected to be a little better.

"We're not going to be 'go' today," Mango announced, thanking everyone for their hard effort.

The experimental flight is meant to last just two minutes. Parachutes will drop the first-stage booster into the Atlantic for recovery. The upper portion of the rocket — all fake parts — will fall uncontrolled into the ocean.

There's no payload on board, just hundreds of sensors to measure pressure, strain and acceleration.

NASA expects to learn a lot, even if it's for another type of rocket. The White House is re-evaluating the human spaceflight program.

Cloudy conditions pose extra concern for the Ares I-X. Rain clouds could cause static electricity to surround the soaring rocket, which lacks proper protection. The result would be disrupted communications, undesirable for a test flight.