Which European space agency is NASA's partner on Hubble?

NASA’s partner on the Hubble Space Telescope is the European Space Agency, or ESA.

Hubble is an international cooperation project rather than a NASA-only mission. ESA joined the Large Space Telescope effort during the 1970s and contributed hardware, including the Faint Object Camera and Hubble’s solar arrays. The partnership agreement between NASA and ESA was signed in 1977.

In return for its contributions, ESA received guaranteed access to a portion of Hubble’s observing time. Astronomers from ESA member countries receive about 15 percent of the telescope’s observing opportunities. ESA personnel have also supported Hubble’s scientific operations, while NASA manages the spacecraft and mission through the Goddard Space Flight Center.

Hubble launched aboard the space shuttle Discovery on April 24, 1990. Its international structure is easy to confuse with later missions: the James Webb Space Telescope involves NASA, ESA, and the Canadian Space Agency, while Hubble’s principal agency partner is ESA. Roscosmos and the Japan Aerospace Exploration Agency are not Hubble’s named agency partners.