Multikilometer lengths of 3.5-GPa (500 ksi) prooftested fiber

Approximately 70 km of fibers were drawn from synthetic silica rods and prooftested at four stresses between 1.4 GPa (200 ksi) and 3.5 GPa (500 ksi). The longest lengths achieved were 17.3 km passing 1.4 GPa (200 ksi), 13.4 km passing both 2.1 GPa (300 ksi) and 2.8 GPa (400 ksi), and 9.3 km passing 3.5 GPa (500 ksi). Tensile tests comparing fibers previously prooftested at 1.4 GPa (200 ksi) with those tested through 3.5 GPa (500 ksi) show no detectable degradation due to the high-strength prooftesting.