The Autonomous Extravehicular Activity Robotic Camera Sprint (AERCam Sprint) is an experiment planned to demonstrate the use of a prototype free-flying television camera that could be used for remote inspections of the exterior of the International Space Station.
The AERCam Sprint free-flyer
is a 14-inch diameter, 35-pound 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 Scott during the STS-87 spacewalk and
Most of the free-flyer's systems are derived from the development of the Simplified Aid for EVA Rescue (SAFER) backpack. The AERCam's thrusters, basic avionics, solid-state rate sensors, attitude hold electronics, nitrogen tank and hand controller are identical to those used on the SAFER. The AERCam thrusters, however, produce eight-hundredths of a pound of thrust while the SAFER thrusters produced eight-tenths of a pound of thrust.
The free-flyer is powered by lithium batteries. Its electrical supply and nitrogen supply are designed to last at least seven hours, the maximum length of a normal spacewalk. The AERCam sphere has a small floodlight built in that is identical to floodlights used on the helmets of spacesuits. Spaced equally around the sphere also are six, small, flashing yellow light-emitting diode lights that make the free-flyer visible to the operator in darkness.
The front of the sphere is marked by stripes and arrows while the back is marked by dots. These markings assist the operator in determining the orientation of the AERCam. A small fabric strap on the sphere serves as a handhold for the spacewalker while deploying and retrieving the free flyer.