About 1,500 Boeing (BA) machinists went on strike at 12:01 a.m. Los Angeles time on Wednesday after last-minute talks broke down between their union and the company unit that operates the Delta rocket program, the Associated Press reported on Wednesday.

A federal mediator was unable to broker an agreement after meeting both sides on Tuesday, the AP reported, citing Gary Quick (search), the chairman of the union's negotiating committee.

"We're out picketing now" at the company's Huntington Beach plant, he told the AP.

A Boeing spokesman did not immediately return a message left on his cell phone, the AP said.

The strike could affect satellite launch facilities operated by Boeing's Integrated Defense Systems unit at Vandenberg Air Force Base in California and Cape Canaveral in Florida, the AP reported.

The launch of one Delta rocket carrying NASA (search) environmental satellites has already been delayed at Vandenberg because of the strike threat, the AP said.

Two weeks ago, locals with the International Association of Machinists and Aerospace Workers in California, Alabama and Florida rejected Boeing's latest offer for a three-year contract.