A lunar swing-by can have important benefits for trajectories leaving from or arriving at Earth. This can reduce trip times, especially in cases where the sail is heavily loaded. A swing-by can also be used to obtain favorable departure or arrival directions relative to Earth. A planetary swing-by could also be employed similar to what is done with coasting spacecraft, but good alignments might not exist due to the requirements for overall optimization of the trajectory. The following table lists some example concepts using beamed laser propulsion as proposed by the physicist Robert L. Forward: Interstellar travel catalog to use photogravitational assists for a full stop Successive assists at α Cen A and B could allow travel times to 75 yr to both stars. Lightsail has a nominal mass-to-surface ratio (σnom) of 8.6×10−4 gram m−2 for a nominal graphene-class sail. Area of the Lightsail, about 105 m2 = (316 m)2 Velocity up to 37,300 km s−1 (12.5% c) . Ref: Projects operating or completed Attitude (orientation) control Both the Mariner 10 mission, which flew by the planets Mercury and Venus, and the MESSENGER mission to Mercury demonstrated the use of solar pressure as a method of attitude control in order to conserve attitude-control propellant. Hayabusa also used solar pressure on its solar paddles as a method of attitude control to compensate for broken reaction wheels and chemical thruster. MTSAT-1R (Multi-Functional Transport Satellite)'s solar sail counteracts the torque produced by sunlight pressure on the solar array. The trim tab on the solar array makes small adjustments to the torque balance. Ground deployment tests NASA has successfully tested deployment technologies on small scale sails in vacuum chambers. In 1999, a full-scale deployment of a solar sail was tested on the ground at DLR/ESA in Cologne. Suborbital tests A joint private project between Planetary Society, Cosmos Studios and Russian Academy of Science in 2001 made a suborbital prototype test, which failed because of rocket failure. A 15-meter-diameter solar sail (SSP, solar sail sub payload, soraseiru sabupeiro-do) was launched together with ASTRO-F on a M-V rocket on February 21, 2006, and made it to orbit. It deployed from the stage, but opened incompletely. On August 9, 2004, the Japanese ISAS successfully deployed two prototype solar sails from a sounding rocket. A clover-shaped sail was deployed at 122 km altitude and a fan-shaped sail was deployed at 169 km altitude. Both sails used 7.5-micrometer film.