Pasadena, Calif. ? Scientists said they may have detected a signal from the world’s first solar sail spacecraft, hours after it suddenly stopped communicating following Tuesday’s launch from a Russian submarine under the Barents Sea.

“Good news,” said Bruce Murray, a co-founder of The Planetary Society, which organized the launch. “We are very likely in orbit … we seem to have a live spacecraft.”

The announcement came after an all-day search for Cosmos 1, a $4 million experiment intended to show that a so-called solar sail can make a controlled flight. The spacecraft was launched at 2:46 p.m., and initial data reception was followed by silence.

The signals were found Tuesday night in a review of data recorded at ground tracking stations on Russia’s Kamchatka Peninsula, Majuro in the Marshall Islands of the Pacific Ocean and at Panska Ves, Czech Republic.

If all went as planned, the spacecraft was to unfurl eight triangular sails, each nearly 50 feet long and just a quarter of the thickness of a trash bag.

Controlled flight, achieved by rotating each sail to change its pitch, would be attempted early next week. Cosmos 1 was supposed to orbit Earth once every 101 minutes and operate for at least a month.

Solar sails are seen as a means for achieving interstellar flight by using the gentle push from the continuous stream of light particles known as photons. Though gradual, the constant light pressure should allow a spacecraft to build up great speed over time, and cover great distances.

This undated artist's rendition shows the Cosmos 1 solar sail in orbit. The solar sail vehicle designed to be propelled by the pressure of sunlight was launched into space Tuesday from a Russian submarine.

Such a craft would not have to carry chemical fuel to propel itself through space, and, according to advocates, would eventually achieve greater speed than a traditional spacecraft.

The Planetary Society is a Pasadena-based organization founded by the late astronomer Carl Sagan. The project was also organized by Murray, who is a former director of NASA’s Jet Propulsion Laboratory, and Louis D. Friedman, a JPL veteran.

Funding came largely from Cosmos Studios of Ithaca, N.Y., a science-based entertainment company that was founded by Sagan’s widow, Ann Druyan.

“Whatever we discover from this mission, if it’s not a success, we’ll still learn from it,” she said. “The way to the stars is hard.”

Built in Russia by the Lavochkin Association and the Space Research Institute of the Russian Academy of Science, Cosmos 1 was under the control of a mission operations center in Moscow.

Japan tested solar sail deployment on a suborbital flight and Russia deployed a solar sail outside its old Mir space station, but neither involved controlled flight.