The giant Sunjammer solar sail, cleared a successful design test that required the deploying beam to stretch a quarter of the sail completely open. Because the Sept. 30 test took place on Earth, gravity and atmosphere made conditions more challenging than they would be in the vacuum of space, the sail’s designers said.

Technicians at L’Garde, the primary contractor for the Sunjammer mission, work carefully with the enormous solar sail.
Credit: Space Services Holdings, Inc.

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“If this test succeeded under these stressing conditions, we certainly anticipate it will work exceedingly well in space,” Nathan Barnes, President of lead contractor L’Garde Inc, said in a statement.

When Sunjammer launches in 2015, it will be the largest solar sail ever flown. Covering an area of almost 13,000 square feet (1,200 square meters), the full sail will span approximately a third the length of a football field. Despite its size, the enormous sail will be only about five millionths of a meter thick, keeping its weight down to 70 pounds (31 kilograms).

The lightweight, reflective material will rely on the pressure generated by sunlight to maneuver it through space. Smaller sails at the end of each of four