The Hubble space telescope carries a variety of instruments including six gyroscopes to ensure stability of the telescope. The six gyroscopes are arranged in such a way that any three gyroscopes can keep the telescope operating with full accuracy. The operating times of the gyroscopes are independent of each other and have an exponential distribution with an expected value of 1/ years. A fourth gyroscope failure triggers the sleep mode of the telescope. In the sleep mode further observations by the telescope are suspended. It requires an exponential time with an expected value of 1/ years to turn the telescope into sleep mode. Once the telescope is in the sleep mode, the base station on Earth receives a sleep signal. A shuttle mission to the telescope is then prepared. It takes an exponential time with an expected value of 1/ years before the repair crew arrives at the telescope and has repaired the stabilizing unit with the gyroscopes. In the mean time the other two gyroscopes may fail. If this happens, a crash destroying the telescope will be inevitable. What is the probability that the telescope will crash in the next T years? What is the probability that no shuttle mission will be prepared in the next T years? Compute these probabilities for the numerical data T = 10, = 0.1, = 100 and = 5.