The B-21 bomber, formerly the Long Range Strike Bomber (LRS-B) is a proposed long-range strategic bomber for the United States Air Force, intended to be a heavy-payload stealth aircraft capable of carrying thermonuclear weapons. Initial capability is expected in the mid-2020s. A request for proposal to develop the aircraft was issued in July 2014. The Air Force plans to purchase 80–100 LRS-B aircraft at a cost of $550 million each (2010 dollars). A development contract was awarded to Northrop Grumman in October 2015.