NASA decided early in the telescope’s development to design the observatory so it could be serviced while in orbit. Instruments were designed as modular units, comparable to dresser drawers that could be easily removed and replaced. In addition, designers equipped the telescope with handholds and other special features to make servicing tasks less difficult for astronauts wearing bulky spacesuits.
By periodically upgrading the science instruments, NASA also reasoned that it could provide the science community worldwide with state-of-the-art technology that took advantage of Hubble’s unique position high above Earth’s obscuring atmosphere.
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