How Hubble Space Telescope Works

By: Craig Freudenrich, Ph.D. & Sarah Goddard

Hubble's Spacecraft Systems: Generating Power and Talking to Ground Control

Hubble's communication system
Hubble's communication system
Photo courtesy STScI and NASA

Hubble isn't only a telescope with highly specialized scientific instruments. It's also a spacecraft. As such, it must have power, communicate with the ground and be able to change its attitude (orientation).

­All of the instruments and computers on board the HST require electrical power. Two large solar panels fulfill this responsibility. Each winglike panel can convert the sun's energy into 2,800 watts of electricity. When the HST is in the Earth's shadow, energy that has been stored in onboard batteries can sustain the telescope for 7.5 hours.­


In addition to generating power, the HST must be able to talk with controllers on the ground to relay data and receive commands for its next targets. To communicate, the HST uses a series of relay satellites called the Tracking and Data Relay Satellite (TDRS) system. Currently, there are five TDRS satellites in various locations in the sky.

Hubble's communication process is also helped by the two main computers that fit around the telescope's tube above the scientific instrument bays. One computer talks to the ground to transmit data and receive commands. The other computer is responsible for steering the HST and various housekeeping functions. Hubble also has backup computers in the event of an emergency.

But what's used to retrieve data? And what happens to that information after it has been collected? Four antennae positioned on the telescope transmit and receive information between Hubble and the Flight Operations Team at the Goddard Space Flight Center in Greenbelt, Md. After receiving the information, Goddard sends it to the Space Telescope Science Institute (STScI) in Maryland, where it's translated into scientific units such as wavelength or brightness.

Learn how Hubble navigates next.