giant inflatable optical lenses for the fake sun
now imagine these are floating way above us and look at the shape of the emitter at the bottom
look at the image in the top image, look familiar?
The IRD was a DoD program to develop large aperture, high precision, low mass, low stowed volume inflatable reflectors and rigidizable structures. The aperture diameter of the parabolic antenna designed and built was 7m with an F/D of unity. Its surface accuracy was measured to be 1.3 mm rms. The antenna film material used was 0.5 mil thick aluminized Mylar. This antenna reflector was one of the first low film stress reflectors (100 psi film stress) built by L.Garde. The lower the material film stress, the lower the mass of the support structure. Rigidization of the torus and struts was achieved with the use of a water-based gel material. Other rigidization methods that could be used are UV rigidization and Sub-Tg rigidization. In the Sub-Tg, the material is allowed to passively cool below its glass transition temperature ensuring a rigid support structure.
