Sails in space

[Marshall Space Flight Center] Huntsville, Ala., U.S.A.

NASA’s nanosatellite NanoSail-D began its slow descent to Earth in April after successfully orbiting the Earth’s upper atmosphere for 95 days since deploying its 100-square-foot sail on Jan. 20. One of its missions has been to test it for possible use in de-orbiting decommissioned satellites and space debris, which is needed to prevent an exponential buildup of space junk around Earth. Made of a thin, polymer sheet of reflective material, the solarsail has made history by demonstrating an elegant and inexpensive method for deploying sails. Only one spacecraft has done anything similar: Japan’s IKAROS probe deployed a solar sail in interplanetary space and used it to fly by Venus in 2010.