ATMOSPHERIC DRAG
The ISS space station orbits approximately 400 km above the Earth. At this altitude, atmospheric drag can overwhelm photon pressure on solar sails. Solar sails cannot effectively navigate in LEO in this rarefied atmospheric wind, which moves at 7.66 km/s relative to the sail surface (27,576 km/h, the orbital speed of the ISS).
To avoid atmospheric drag, prototype Pico Solar Sails should be positioned in the lee of the space station, to shield the sail surfaces from bombardment by fast-moving air molecules. Once in a protected position, the sails can be directly observed and radio-controlled from the ISS cupola during the daylight portions of the space station orbit. After days of testing, orbital decay will cause the sacrificial prototypes to burn up in the atmosphere.
OBSERVATION OF PROTOTYPES FROM ISS CUPOLA
See: Mass Launch System
See: MLS Spaceport