Aid For Extravehicular Activity Rescue
SAFER, is a small, self-contained, propulsive
backpack device that can provide free-flying mobility for a spacewalker. This jetpack’s primary purpose
is to safely return the spacewalker to the ISS if he or she accidentally becomes untethered. Attached
to the spacesuit’s display and control module is a hand controller, similar to a joystick, which operates
various combinations of thrusters to propel the astronaut back to the safety of the ISS. Each of the
24 fixed-position thrusters expels nitrogen gas with a force of 3.6 newtons (less than one pound of force).
The astronaut can move the SAFER up and down, back and forth, and side to side, and yaw, pitch, and
roll by manipulating the hand controller. The nitrogen is contained in highly pressurized
tanks that cannot be recharged in orbit. If the SAFER is used, a Space Shuttle must bring a new unit to the
ISS. Used units will be brought back to Earth and recharged for future use.