US-based aerospace and defence technology company Northrop Grumman has completed the assembly of Nasa’s James Webb Space Telescope.

The milestone was achieved after the two halves, namely James Webb Space Telescope Spacecraft Element (SCE) and Optical Telescope Element/Integrated Science Instrument Module (OTIS), were joined together.

Northrop Grumman carried out the work at its facility in Redondo Beach, California, US.

The preparations to connect the two halves began seven years ago when work started on the design and build of the flight hardware and tools required for the task.

Engineers had to align the 8,000lb, 131in OTIS with six launch load interfaces in a two-phase operation.

The two sections have undergone environmental testing separately.

Northrop Grumman James Webb Space Telescope vice-president and programme manager Scott Willoughby said: “This milestone marks a major achievement for all of us at Northrop Grumman and Nasa.

“Seeing the full observatory for the first time further reinforces our commitment to mission success. There is still more work to be done, but it is a great feeling seeing something that was once a concept, become reality.

In the next few months, the James Webb Space Telescope will be prepared for acoustic and vibration environmental testing in 2020.

The telescope will be launched in 2021 and is expected to assist in providing more insight into and beyond the mysteries in the solar system.

The space science observatory programme is led by Nasa and its partners, the European Space Agency (ESA) and the Canadian Space Agency.