Russian space officials have delayed until April a test launch of a solar-sail spacecraft, local media reported Tuesday.

Lidia Avdeeva, a spokeswoman for the Lavochkin production and science association, told the Russian ITAR-TASS news agency the launch of an unmanned spasecraft with eight triangular sail blades, each 16.5 yards long, had been planned for March, but was postponed because of “the sheer volume of preparatory work.”

The spacecraft, called Cosmos 1, is planned for launch on a Volna rocket from a converted SS-N-18 Russian submarine in the Barents Sea. The mission is expected to end within a month as the mylar of the blades degrades in sunlight.

“The experiment is to confirm the possibility of controlling the craft using sunlight pressure,” Avdeeva said.

The spacecraft is being buiilt under contract to the U.S. Planetary Society.

An attempt in 2001 to test a spacecraft with two sail blades failed because the craft failed to deploy from its booster rocket.