The AERCam Sprint free-flyer is a , 35-pound (16 kg) sphere that contains two television cameras, an avionics system and 12 small nitrogen gas-powered thrusters. The sphere, which looks like an oversized soccer ball, was released by Mission Specialist Winston E. Scott during the STS-87 spacewalk and flew freely in the forward cargo bay for about 30 minutes. The free-flyer was remotely controlled by Pilot Steven W. Lindsey from the Shuttle's aft flight deck using a hand controller, two laptop computers and a window-mounted antenna. The AERCam is designed to fly very slowly at a rate of less than one-quarter of a foot per second. Remote control of the AERCam is performed through two-way UHF radio communications, with data regarding the status of the free-flyer's systems transmitted back to the operator. Television images are transmitted back to the operator via a one-way S-band communications link. During the experiment operations, live television images were also relayed via Columbia to Mission Control. Two miniature color television cameras are mounted on the free-flyer, one with a 6 millimeter lens and another with a 12 millimeter lens. The exterior of the free-flyer sphere is covered with a layer of Nomex felt to cushion any inadvertent contact with a spacecraft surface and prevent damage.