2020RAA....20...44W

With an initial requirement to make observations a minimum of 5-10 years, Hubble Space Telescope (HST) has continued to operate well for 30 years. It has relied upon five servicing missions to repair and replace essential components. Since the final Space Shuttle mission 10 years ago, it has avoided major breaks in its operation, with the only serious effects of aging in space being a progressive deterioration in the performance of the gyroscopes and sensitivity of the instrument detectors. A number of factors were important in making HST a scientific landmark. Ground-breaking discoveries have been made with HST - the most important being the discovery of cosmic acceleration. When HST operation ceases, future observations in space should be assured with successful operation of major missions now planned by NASA, ESA, and the Chinese and Japanese Space Agencies.