[erickejah]

In the gravity probe mission; a perfect gyroscope was used to make measurements relevant to the mission. The gyroscope was added with a layer of niobium, then brought down to low temperatures to allow superconductivity to happen. The London effect makes the niobium ball generate its own magnetic field. How is the London effect related to the Meissner effect(Quantum lock)?

Thanks in advance

edit:
What about the Josephson effect?