216 Bernd Kroplin Addtional ifatable Braking Device Man Infatable Brakng Device FREGAT Upper Stage Thermal Protection Filng Sysem Fig.5.Inflated reentry capsule[5] 3 Structures with Full Gas Volume The inflated tennis court-halls of the last century are a well known example for this class of structures,see Fig.6.Since the air pressure has to be maintained permanently for the stability of the structure,the doors are designed as double door pressure lock.Another example to overcome the totally inflated space inside is to inflate only the roof.Fig.7 gives an example.For adaptation to different load cases, e.g.snow,a spherical pressure chamber is included. Fig.6.Tennis court cover [6],permanent 4 Buoyancy-Structures If the inside space of the structure is filled with a gas lighter than air,an upward force is created,which is called buoyancy.The buoyancy depends on the density difference between the internal and the external medium.The principle has been used since the 18th Century.1 m3 buoyancy gas,e.g.helium,can roughly carry 1 kg216 Bernd Kroplin ¨ Fig. 5. Inflated reentry capsule [5] 3 Structures with Full Gas Volume The inflated tennis court-halls of the last century are a well known example for this class of structures, see Fig. 6. Since the air pressure has to be maintained permanently for the stability of the structure, the doors are designed as double door pressure lock. Another example to overcome the totally inflated space inside is to inflate only the roof. Fig. 7 gives an example. For adaptation to different load cases, e.g. snow, a spherical pressure chamber is included. Fig. 6. Tennis court cover [6], permanent 4 Buoyancy-Structures If the inside space of the structure is filled with a gas lighter than air, an upward force is created, which is called buoyancy. The buoyancy depends on the density difference between the internal and the external medium. The principle has been used since the 18th Century. 1 m3 buoyancy gas, e.g. helium, can roughly carry 1 kg