Apparently, the differences between the Democratic presidential candidates can no longer be restricted to this world. Thursday night, Hillary Clinton made space travel an issue in the campaign. According to the New York Observer, Clinton told a crowd of nearly 3,000 people that "'one of the differences' between her and Obama ... is that she 'want[s] Houston to remain the capital of the space race.'"

It just so happened that Clinton was speaking at the Delmar Fieldhouse in Houston. NASA's manned spaceflight program operates out of the Johnson Space Center, also located in Houston. MSNBC points out that the Johnson Space Center "employs 3,000 federal workers and as many as 14,000 contracted employees."

Clinton suggested that if she is not elected president, spacecraft manufacturing runs the risk of being outsourced. "I don't want to be sending Americans into space on a Chinese- or a Russian-made vehicle," she said. "I want that work done right here in Houston."

Clinton's remarks were a jab at Obama's plan, released in November, to delay funding to NASA's Constellation program for five years. The goal of the Constellation program is to create a "lunar outpost" that would serve as a way station for a potential manned space flight to Mars. Obama wants to use the money instead to help fund his education-reform plan (details here), which will cost $18 billion a year.

Hillary isn't the only Clinton who has been speaking about celestial matters with Texas voters. On Wednesday, according to MSNBC, Bill Clinton reaffirmed Hillary's commitment to NASA during a speech in Houston. Hillary's opponents, Bill said, "say we should downgrade man space travel and upgrade robotic travel."

But the most notable quote from Bill's speech wasn't about space. Addressing an Obama ad that Clinton said told Texas voters "how terrible things were in the '90s," Clinton said, "If you believe things were bad in the '90s, just as bad as in this decade, and you believe everybody should be eliminated from being considered for president if they did anything good, I think you should vote for him." If not, he added, you should vote for Hillary.