Genesis launch delayed again

A drawing of the Genesis spacecraft

(CNN) -- The launch of NASA's Genesis spacecraft aboard a Boeing Delta II rocket, has been postponed again to give engineers more time to test a power unit similar to one on the satellite.

"They need some additional test and evaluation time," according to NASA spokesman George Diller.

The launch now would take place no earlier than Wednesday, August 1, at 12:31 p.m. EDT from Cape Canaveral.

The Genesis launch, originally scheduled for Monday, was delayed after a vendor notified NASA that a power supply undergoing tests for another mission malfunctioned when it was placed in a simulated space environment.

Specifically, Diller said, the power unit failed during a simulated solar flare.

Genesis is designed to fly 930,000 miles toward the sun, gather bits of the solar wind and bring them back to Earth in 2004.

Engineers will continue running tests until early Wednesday and make a decision about launch just hours before the launch window opens, according to Diller.

Even if the power supply issue clears up, the weather may not. Diller said there is a 60 percent chance of bad weather at launch time Wednesday.