Orbiting the Earth at an altitude of 340 miles (547 km) above its surface, the Hubble Telescope explores the universe. Here are the facts about this scientific instrument.

The Hubble Telescope was named in honor of astronomer Edwin Powell Hubble, a scientist who discovered that distant clouds of light were other galaxies, showing that the Milky Way is just one of many. Additionally, in 1929, Hubble determined that the farther a galaxy is from Earth, the faster it appears to be moving away.

    The Hubble Telescope was launched into orbit aboard the space shuttle Discovery on April 24, 1990. It captured its first image about a month later, on May 20, that of Star cluster NGC 3532.

    Traveling at 17,000 mph (27,359 km/hr), the Hubble completes an orbit of Earth every 95 minutes. Since its launch, the telescope has orbited the Earth close to 190,000 times. It doesn’t travel to any celestial objects — stars, planets, or other galaxies — it provides pictures of them.

    The telescope’s views are clear and concise because it’s located above the Earth’s atmosphere, which can distort light and block wavelengths,    and where clouds can obstruct the view. The Hubble cannot capture images of Earth because its orbit is too fast for the camera’s exposure time.

    The Hubble is 43.5 feet (13.3 m) in length, about the size of a long school bus, with a diameter of 14 feet (4.3 m). When it was launched, it weighed 24,000 lbs (10,800 kg), but now weighs in the neighborhood of 27,000 lbs. (12,200 kg). Periodic service missions by astronauts keep the telescope in optimal working order, updating its equipment to extend its life.    There have been five such missions, beginning in 1993, with the most recent in 2009.

    The telescope’s primary mirror measures 94.5 inches (2.4 m) in diameter, weighing 1,825 lbs. (828 kg). It collects its energy from two 25-ft. (7.6-m) solar panels, storing it in six nickel-hydrogen batteries, with a capacity equal to about 22 average car batteries.

The life expectancy of the Hubble was estimated at 15 years at the time of its launch. The successful servicing missions have kept the device productive, with continual operation expected for at least another decade. Because of atmospheric drag, a force that affects the orbits of satellites that are in a low-Earth orbit, the Hubble’s altitude is gradually decreasing, requiring its return to Earth, unless a propulsion module can boost it into a higher orbit.

    The Hubble is extremely accurate, able to lock onto an object with an equivalency of shining a laser on a human hair a mile away. Its farthest observation is that of the Galaxy GN-z11, about 13.4 billion light years away. Just how far is that? With a light-year equivalent to the distance light travels in one year, multiply that figure of about 6 trillion miles (9 trillion km) by 13.4 billion!

    Over the years, the Hubble has made close to 1.5 million observations. The cost of this mission has been about $16 billion since its initial inception in 1977. However, this doesn’t include the cost of its space shuttle launch or any of the five servicing missions.