WASHINGTON – The Defense Department first proposed Star Wars. Now it wants Star Trek.

DARPA, the Pentagon’s research agency that helped foster the Internet, wants someone to dream up a way to send people to a star.

The winner will get half a million dollars for the idea. This month, 150 competitors answered the federal government’s initial call for private sector cosmic ideas. The plan is to make interstellar travel possible in about a century.

The Defense Department devised a space-based missile defense system in the 1980s known as “Star Wars.” Its new trademarked 100-year Starship Study concept comes from the Defense Advanced Research Projects Agency, which is spending a total of $1 million on the project. After presentations this fall at a conference in Orlando, Fla., DARPA will decide in November who gets the money.

The grant would be “seed money” to help someone start thinking about the idea and then get it off the ground in the private sector, David Neyland, director of DARPA’s tactical technology office, said Thursday.

But even the nearest star beyond our sun is 25 trillion miles away. The fastest rocket man has built would take more than 4,000 years to get there. This isn’t just about thinking new rocket methods, Neyland said. It’s also about coping with extended life in space, raising issues of medicine, agriculture, ethics and self-reliance, he said.

Among those who showed an interest in the project is millionaire scientist Craig Venter, one of those who mapped the human genome and is now working on artificial life and alternative fuels.