Which company was the primary contractor for JWST?

Northrop Grumman was the primary, or prime, contractor for the James Webb Space Telescope. NASA selected the company to lead the observatory’s industrial development and assemble its major spacecraft and telescope elements.

The project involved a large network of subcontractors. Ball Aerospace contributed major optical and structural work, while other companies supplied instruments, detectors, electronics, and thermal systems. Northrop Grumman’s role was therefore broader than simply manufacturing a single component: it integrated the observatory into a flight-ready spacecraft.

The telescope was assembled and tested through a long, complex development program. Its two major halves—the spacecraft and the telescope—were connected at Northrop Grumman’s facility in Redondo Beach, California, in 2019.

Northrop Grumman is sometimes confused with NASA, ESA, or the launch provider. NASA led the mission, ESA supplied major contributions and the Ariane 5 rocket, and Northrop Grumman served as the main industrial contractor.