Before the year's end, a team of civilians united by a passion for space travel will launch a spacecraft into orbit to test a new space-traveling technology.

The mission, which will use a solar sail to carry a spacecraft ever farther from Earth, is the first use of a propulsion technology that may pave the way for interstellar flights.

"Our job is just to prove this technology," project director Louis Friedman told SPACE.com. "If our craft goes just 10 kilometers on the solar sail, then it's a success." Friedman is also executive director of the Pasadena-based Planetary Society.

"I frankly don't know if this will work," said Friedman. "But our spacecraft is really coming together."

Cosmos 1 is being built at the Babakin Space Center, where engineers are incorporating the small, three-foot (one-meter) wide spacecraft into the nosecone of a Volna rocket originally developed as a submarine-launched intercontinental ballistic missile.

Ann Druyan, Cosmos 1 program director and CEO of Cosmos Studios, said the conversion of a weapon of mass destruction into a tool of science is an added benefit of the solar sail mission.

"For us, the solar sail represents a baby step into the cosmic community," she told SPACE.com. "This is an opportunity to stretch the human horizon."

The Planetary Society, founded by Druyan's late-husband Carl Sagan, Friedman and planetary scientist Bruce Murray, consists of about 100,000 members, many of whom helped contributed donations - ranging from the $100,000s to just $5 - to raise the $4 million necessary for Cosmos 1.

The Cosmos 1 rocket will be loaded into the Russian nuclear submarine, transported out to the Barents Sea, where and launched into a 497-mile (800-kilometer) Earth orbit. After a few days of spacecraft checkout time, the eight-bladed solar sail will open up like a giant space flower.

Each of the sail's petals is 47 feet (about 14 meters) long, composed of thin mylar and rolled into a space the size of a coffee can before launch. Cosmos 1 ground controllers plan to open the sail, four blades at a time, by inflating hollow tubes that run along the sides each blade with nitrogen gas. Each blade can also be rotated to present either its full face or just an edge toward the Sun, allowing researchers to control the amount of force striking the sail.

"So when you're in Earth orbit, it's kind of like you're tacking in a harbor," said Jim Cantrell, a consultant for the Cosmos 1 mission. A mechanical engineer by training, Cantrell added that if Cosmos 1 always presented a full face toward the Sun, it would never gain any positive velocity.

For example, the kick Cosmos 1 would get as it orbited away from the Sun, with photons pushing the sail from behind, would be cancelled out as it rounded Earth and photons began to strike the front of sail.

"It's an added complexity when you're in travelling in orbit," said Cantrell. "In open space it wouldn't be a problem."

The propelling force behind solar sails stems from photons of light, not the solar wind of charged particles blowing outward from the Sun.

"The sail is basically a giant mirror," said Friedman. The pressure of sunlight bouncing off the sail adds momentum and pushes the spacecraft.

The process is slow and may not be the right choice for jet setting around the Solar System. Cosmos 1, for example, would take a year and a half to reach the Moon, whereas a chemical rocket has done the job in a few days.

"The amount of force on a solar sail is about the equivalent of the weight of a postage stamp," said Hoppy Price, a senior engineer at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. "But it continues, day after day, month after month and year after year. A chemical rocket lasts only a few minutes."

In a space trip out to about 50 astronomical units (AU), which is 50 times the distance between the Earth and the Sun, a solar sail craft could reach speeds of about 100 kilometers a second. Lasers could also be launched ahead of time along the spacecraft's flight path to provide light boosts to the sail. Chemical rockets, on other hand, results in speeds of up to 15 to 20 kilometers per second.

Price told SPACE.com that NASA researchers are also busy developing their own solar sail methods, which should undergo deployment tests in 2005 and a possible flight test in 2007. Meanwhile researchers with the European Space Agency (ESA) and the German Aerospace Center (DLR) have conducted ground tests of their own sail material.

The Cosmos 1 mission, however, will be the first solar sail to be unfurled in space, allowing researchers to study the effectiveness of the deployment process and ability to control the sail. The mission should also demonstrate the sail's ability to withstand micrometeorite impacts and other space hazards. Cosmos 1 scientists plan to make their findings public in the hopes of boosting solar sail research.

While the mylar material of Cosmos 1's sail isn't the best choice for an interplanetary mission, it should work fine in a proof of concept flight. "Mylar is a polyester," Price said. "It's lightweight, but it doesn't take high temperatures well, or radiation."

NASA missions for solar sails are expected to be long-duration flights requiring hardy material that can withstand intense heat as well as high radiation doses, he added.

The upcoming launch won't be the first for Cosmos 1 planners, but it will be the project's first complete flight.

In July 2001, project managers launched a suborbital version of Cosmos 1 that never opened its two-bladed sail. "It launched okay, went up just fine and we were all cheering," said Kent Gibson, Cosmos Studios president. But the spacecraft failed to separate from its third stage, but continued on its ballistic flight path toward the Kamchatka peninsula. It has not been recovered.

"We've had some tough times, and we'll certainly have more tough times," said Friedman.  But Cosmos project designers are confident in their complete, eight-bladed solar sail.

And even if Cosmos 1 fails, Druyan added, mission scientists will still learn more from the launch than if they hadn't tried at all.

Cosmos 1 researchers said they hope to launch their spacecraft by October, although there will be blackout period when the submarine they plan to use will be unavailable due to the schedule of Russian naval exercises.