Florida's primary on Tuesday is a high stakes, winner-takes-all contest. At stake: 50 delegates and a victory in the nation's largest swing state. It is also the first contest to have a significant number of Republican Hispanic voters.

Gingrich, Romney sharpen attacks

Newt Gingrich opened a new line of attack against Mitt Romney, focusing on his wealth and ties to Goldman Sachs Group Inc., a firm he says added to the housing crisis. His remarks were designed to blunt criticism of his work for Freddie Mac, the government-backed mortgage-lending company that Republicans link to the financial meltdown. "We're not going to beat Barack Obama with someone who owns Swiss bank accounts, Cayman Island accounts," he told a Tea Party crowd in Mount Dora, Florida. "I am running for president to represent you, not to represent the Washington establishment, not to represent Goldman Sachs."

Meanwhile, Romney told supporters in Jacksonville that the choice they face was between a businessman and "someone who has been part of the culture of Washington for the last 35 years."

Experts weigh in on lunar base plan

Newt Gingrich vowed that by the end of his second term as president, the U.S. flag would once again be planted on the moon. The United States, he said, would have a permanent lunar base.

His comments created big headlines Thursday on the Space Coast. The question is whether this is science fiction.

"I think it's an aggressive mission," said Robert Whelan, an aerospace executive with Harris Corp. That was his way of saying that building a lunar base by January 2021, or even putting a single human bootprint on lunar soil, would be difficult.

Gingrich said he would transform NASA's culture and rely heavily on private industry. He said he'd use 10 percent of the NASA budget, which would amount to nearly $2 billion a year, to create prizes for entrepreneurs to achieve space flight milestones. Edward Ellegood, a space policy analyst at Embry Riddle Aeronautical University, doubted that that strategy would work for such an ambitious mission. But retired shuttle worker John Weiler, 67, liked what he heard. He said: "Probably the best speech I've heard in this political season so far. Visionary."