WASHINGTON, Oct. 18 -- Put the resumes of the two Senate candidates from Florida side by side, and some similarities jump out.

Both men served for years in the House of Representatives. Both men attended the University of Florida. Both men had leadership roles in Key Club, the high school community service organization. Both men are in their mid 50s.

Both candidates are even named Bill.

But Democratic candidate C. Bill Nelson has one line on his resume that Republican Bill McCollum does not -- payload specialist.

Nelson, center, and the crew of the Space Shuttle Columbia.

In 1986, while a Democratic congressman representing Floridas Space Coast area, Nelson became the second member of NASAs politician-in-space program, following Senator Jake Garn, a Republican from Utah.

Aboard flight STS-61C on the shuttle Columbia, Nelson was involved with a University of Alabama at Birmingham experiment that hoped to grow crystal proteins in outer space for cancer research and served as the subject for medical tests examining the effects of microgravity on the human body.

The space agency chose Nelson and Garn for slots on the shuttle missions because of their positions on key congressional panels that oversaw NASA. Nelson was the chairman of the House space subcommittee and Garn headed the Senate appropriations subcommittee that oversaw NASAs budget.

Nelson, who left Washington in 1992 to make a bid for the Florida governors mansion that failed, has already become one of the few politicians to make space exploration an issue in the November elections.

His campaign hoped to center a September debate held near Cape Canaveral around space issues, but both the events sponsors and the McCollum campaign demurred, opting to focus on statewide issues.

In August, Nelson -- now Floridas insurance commissioner -- told Florida Today that he would make a piloted mission to Mars a legislative priority.

"In my lifetime, what I want to see is a mission from Planet Earth to Planet Mars with an international crew that returns safely," Nelson told the newspaper. "I think we can do that. We have the technology, we just have to have the will to do."

Nelson joins a short list of candidates who have pledged their support for such a mission, including McCollum, a member of Congress from central Florida.

"Congressmen from Florida as a rule have tended to be very supportive, because even if their district doesnt encompass the space center, they know how important the industry is to the state as a whole," said Michael Gilbrook, a space activist from Orlando, Florida, who serves on the board of the National Space Society.

During his tenure in Congress, Nelson was an ardent advocate for NASA and space exploration. He was the prime sponsor on a bill that would fund construction of the shuttle Endeavor, NASAs replacement for the shuttle Challenger.

The Endeavor bill may have had some personal significance for Nelson -- his shuttle flight touched down just 10 days before the Challenger lifted off on its doomed mission.

Critics say, however, that as a congressman, Nelson was too protective of the space agency, charging that he used his position as chair of the space subcommittee to act as a booster for NASA, instead of as an independent check on the agency.

"In my lifetime, what I want to see is a mission from Planet Earth to Planet Mars with an international crew that returns safely. I think we can do that. We have the technology, we just have to have the will to do."

Nelson and the space agencys other backers on the space committees were "NASAs biggest fans when you get right down to it," Donald E. Day, an auditor with the General Accounting Office, Congress investigative arm, told the New York Times in a 1986 article.

But Robert Walker, a former Republican congressman from Pennsylvania who served with Nelson on the space subcommittee, said that Nelsons advocacy for NASA was an effort to support his constituency, which included a large number of space industry workers.

"The great difference was that he represented a major space center and he focused on those things that were of interest to his constituents," said Walker, now the chairman and chief executive officer of the Wexler Group lobbying firm. "If there was a problem in terms of Bills service, it was that he did not have much room to maneuver."

"I do think he was seen pretty much as a cheerleader. He had thousands of employees in his district who depended on NASA," said Walker, who is also serving as a space policy adviser to the presidential campaign of Texas Governor George W. Bush.

But, he said, the Science Committee often attracts members of Congress who have major space or scientific facilities in their district.

Those criticisms dont seem to have hurt Nelson with Florida voters. A recent poll conducted by Mason-Dixon Polling and Research, a Washington-based firm, for the Orlando Sentinel showed Nelson leading McCollum 44 percent to 36 percent. The poll of 803 registered voters has a margin of error of plus or minus 3.5 percent.

Gilbrook said that space activists would probably be satisfied with either candidates stance on space.

"I think both men recognize that this is an important part of Floridas employment base and our technology base, but also for the nation as a whole," he said. "I think that both men would continue to look out for NASA and space interests."