Superconductivity and carbon nanotubes, are Type I, while almost all impure and compound superconductors are Type II. Conversely, a spinning superconductor generates a magnetic field, precisely aligned with the spin axis. The effect, the London moment, was put to good use in Gravity Probe B. This experiment measured the magnetic fields of four superconducting gyroscopes to determine their spin axes. This was critical to the experiment since it is one of the few ways to accurately determine the spin axis of an otherwise featureless sphere. Superconductivity was discovered on April 8, 1911 by Heike Kamerlingh Onnes, who was studying the resistance
Heike John Heike John Heike John (now Heike Walpot; born 19 June 1960) is a retired German swimmer and former astronaut candidate. She won a bronze medal at the 1977 European Aquatics Championships. She competed at the 1976 Summer Olympics in the 100 m and 200 m backstroke events but did not reach the finals. During her career she won five national titles in the 100 m (1977) and 200 m (1977, 1978) backstroke and 200 m medley (1977, 1978). She missed the 1980 Summer Olympics because of their boycott by West Germany. After her swimming career, she studied medicine at RWTH