Suited for Spacewalking pdf - Virtual Astronaut

Exploration BriefBending Under PressureContextMaintaining proper pressure inside a spacesuit isessential to astronaut survival during a spacewalk. Alack of pressure will cause body fluids to turn to gas,and resulting in death in a few seconds.While makingspacewalks possible, pressure produces its ownproblems. An inflated spacesuit can be very difficultto bend. In essence, a spacesuit is a balloon with anastronaut inside.The rubber of the balloon keeps inoxygen that is delivered to the suit from pressurizedoxygen tanks in the backpack. But, as pressureinside the balloon builds up, the balloon’s wallsb e c ome stiff, making normal bending motion simpossible. Lack of flexibility defeats the purposeof the spacewalk–mobility and the ability to dowork in space.Spacesuit designers have learned that strategicallyplaced breaking points at appropriate locations outsidethe pressure bladder (the balloon-like layerinside a spacesuit) makes the suit become morebendable.The breaking points help form joints thatbend more easily than unjointed materials. Othertechniques for promoting bending include stitchingfolds into the restraint layer that spread apart andcontract with bending and building joints into therestraint layer like ribs on vacuum cleaner hoses.Objective• To observe how an external joint in a spacesuitarm segment increases bendability of the segment.Materials and Tools ChecklistTwo long balloons3 heavy-duty rubber bandsProcedureS tep 1. I n f l a te a long balloon and tie it off. The ba l l o o nre p resents the pre s s u re bl ad d er of a spacesuit arm .Let students try to bend the balloon in the middle.S tep 2. I n f l a te a second long ba l l o o n .As you are inflat -ing the ba l l o o n ,slip heavy - d u ty ru b b er ba n d so ver the balloon at intervals so that as inflationcontinues the balloon is pinched by the ru b b erba n d s . It is easier to accomplish this by pre -inflating the ba l l o o n . It may be necessary tod o u ble the ru b b er band to pinch the ba l l o o nenough for the demonstra t i o n . Have stu d e n t sc o m p a re the force re q u i red for bending this ba l -loon with the force needed for the first ba l l o o n .Suited for Spacewalking An Activity Guide for Technology Education, Mathematics, and Science, EG-1998-03-112-HQ • 8 7