Hubble Essentials: Quick Facts

Hubble is nearly the size of a large school bus — but it can fit inside a space shuttle cargo bay.
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Hubble's two mirrors were ground so that they do not deviate from a perfect curve by more than 1/800,000th of an inch. If Hubble's primary mirror were scaled up to the diameter of the Earth, the biggest bump would be only six inches tall.
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Hubble's Name
NASA named the world's first space-based optical telescope after American astronomer Edwin P. Hubble (1889—1953). Dr. Hubble confirmed an "expanding" universe, which provided the foundation for the Big Bang theory.

Launch: April 24, 1990 from space shuttle Discovery (STS-31)
Deployment: April 25, 1990
Mission Duration: Up to 20 years
Servicing Mission 1: December 1993
Servicing Mission 2: February 1997
Servicing Mission 3A: December 1999
Servicing Mission 3B: February 2002
Servicing Mission 4: May 2009

Length: 43.5 ft (13.2 m)
Weight: 24,500 lb (11,110 kg)
Maximum Diameter: 14 ft (4.2 m)

Cost at Launch
$1.5 billion

Spaceflight Statistics
Orbit: At an altitude of 298 nautical miles (552 km, or 343 miles), inclined 28.5 degrees to the equator (low-Earth orbit)
Time to Complete One Orbit: 97 minutes
Speed: 17,500 mph (28,000 kph)

Optical Capabilities
Hubble Can't Observe: The Sun or Mercury, which is too close to the Sun
Sensitivity to Light: Ultraviolet through infrared (115—2500 nanometers)
First Image: May 20, 1990: Star Cluster NGC 3532

Data Statistics
Hubble transmits about 120 gigabytes of science data every week. That's equal to about 3,600 feet (1,097 meters) of books on a shelf. The rapidly growing collection of pictures and data is stored on magneto-optical disks.

Power Needs
Energy Source: The Sun
Mechanism: Two 25-foot solar panels
Power usage: 2,800 watts

Pointing Accuracy
In order to take images of distant, faint objects, Hubble must be extremely steady and accurate. The telescope is able to lock onto a target without deviating more than 7/1000th of an arcsecond, or about the width of a human hair seen at a distance of 1 mile.

Hubble's Mirrors
Primary Mirror Diameter: 94.5 in (2.4 m)
Primary Mirror Weight: 1,825 lb (828 kg)
Secondary Mirror Diameter: 12 in (0.3 m)
Secondary Mirror Weight: 27.4 lb (12.3 kg)

Power Storage
Batteries: 6 nickel-hydrogen (NiH)
Storage Capacity: equal to 20 car batteries