What is the mass of the Hubble Space Telescope in kilograms?

The mass of the Hubble Space Telescope is 11,110 kilograms. That figure is commonly given as Hubble’s mass at launch, equivalent to about 24,500 pounds. The observatory was carried into orbit inside Space Shuttle Discovery’s payload bay during mission STS-31 in April 1990.

Hubble is much more than a mirror in a tube. Its mass includes the primary and secondary mirrors, scientific instruments, computers, pointing hardware, solar arrays, batteries, communications equipment, structural components, and thermal-control systems. The telescope is roughly the size of a large school bus, measuring about 13.2 metres long and 4.2 metres wide at its widest point.

The number can be confusing because Hubble’s mass has changed over time. Astronauts replaced instruments, batteries, gyroscopes, insulation, and other hardware during five servicing missions, so later technical documents may list a different mass. The 11,110-kilogram figure is the standard launch-era value associated with the original observatory. It should not be confused with the mass of the shuttle, the launch stack, or the telescope’s individual mirror.