WASHINGTON - NASA briefed senior White House officials Wednesday on its plan to spend $100 billion and the next 12 years building the spacecraft and rockets it needs to put humans back on the Moon by 2018. The U.S. space agency now expects to roll out its lunar exploration plan to key Congressional committees on Friday and to the broader public through a news conference on Monday, Washington sources tell SPACE.com. U.S. President George W. Bush called in January 2004 for the United States to return to the Moon by 2020 as the first major step in a broader space...