Orbiting 360 miles above Earth, the Hubble Space Telescope is positioned high above the blurring effects of the atmosphere. From this vantage point, it captures images with 10 times the typical clarity of any ground-based telescope and views not only visible light but also wavelengths1 of near-infrared and ultraviolet light that cannot reach Earth's surface. To operate from orbit, the observatory works like any other scientific or imaging spacecraft; it converts the optical data it collects into electrical signals that are transmitted back to Earth. It must also withstand the airless, high-radiation, and harsh thermal environment of space.

Unlike most other spacecraft, however, Hubble was designed to be serviced periodically by astronauts and so was built with modular components that are astronaut-friendly to handle and replace. This design strategy has enabled it to operate longer than ordinary spacecraft and to benefit from the technological advancements of the last two decades. Astronauts have visited the telescope five times to upgrade its computers, mechanisms, and instruments. These servicing missions have kept the observatory at the forefront of discovery by providing it with increasingly sensitive and accurate components. The last of these servicing calls was in May 2009.


1. the distance between one light wave from any one point to the next point of corresponding phase
1
Choose the correct answer.
Which statement best expresses the central idea of the passage?

A.
The Hubble observatory lacks the latest technological advancements of the last decade.
B.
The Hubble observatory is designed to function and be maintained while in orbit.
C.
The Hubble observatory requires astronauts to regularly repair it due to its failing parts.
D.
The Hubble observatory is designed to study planets from the perspective of space.