The fully assembled James Webb Space Telescope with its sunshield and “unitized pallet structures” (which fold up around the telescope for launch) are seen partially deployed to an open configuration to enable telescope installation.

NASA's next big space observatory has finally come together.

Engineers have joined both halves of the $9.7 billion James Webb Space Telescope , which is scheduled to launch in March 2021, NASA officials announced today (Aug. 28).

"The assembly of the telescope and its scientific instruments, sunshield and the spacecraft into one observatory represents an incredible achievement by the entire Webb team," Webb project manager Bill Ochs, of NASA's Goddard Space Flight Center in Greenbelt, Maryland, said in a statement .

"This milestone symbolizes the efforts of thousands of dedicated individuals for over more than 20 years across NASA, the European Space Agency, the Canadian Space Agency, Northrop Grumman and the rest of our industrial and academic partners," Ochs added.

Related: Building the James Webb Space Telescope (Gallery)

Image 1 of 3 NASA's James Webb Space Telescope, the agency's next giant space telescope, is seen completely assembled for the first time at Northrop Grumman’s facilities in Redondo Beach, California in this image released Aug. 28, 2019. (Image credit: NASA/Chris Gunn) Image 2 of 3 A side view of the James Webb Space Telescope after its spacecraft and telescope sections were assembled. (Image credit: NASA/Chris Gunn) Image 3 of 3 The James Webb Space Telescope's optical section (top) is carefully lowered into place on its Spacecraft Element in this view taken just before integration. (Image credit: NASA/Chris Gunn)

The recent work took place at the Redondo Beach, California, facilities of Northrop Grumman, the prime contractor for Webb, which NASA bills as the successor to the iconic Hubble Space Telescope .

Using a crane, engineers gently lowered the telescope element, which consists of the optical and scientific gear, onto the spacecraft body. Webb's complex, foldable sunshield, which will keep the telescope's instruments cool during operation, was already connected to the spacecraft segment.

The team then connected the two halves mechanically. Technicians still need to make, and then test, the electrical connections between the pieces, NASA officials said.

The assembly milestone was a long time coming; the Webb Space Telescope mission has endured a series of delays and cost overruns. Since 2009, for example, the project's price tag has almost doubled, and its target launch date has been pushed back by nearly seven years.

But the telescope's great scientific potential makes all that hard work and struggle worthwhile, NASA officials have said. The powerful Webb, which is optimized to view the universe in infrared light, will allow astronomers to address some of the biggest cosmic questions once it's up and running at the sun-Earth Lagrange Point 2, a gravitationally stable point in space about 930,000 miles (1.5 million kilometers) from Earth.

Researchers will use the observatory to hunt for signs of life in the atmospheres of nearby alien planets, for example, and to study the formation of the universe's first stars and galaxies about 13.5 billion years ago.

"This is an exciting time to now see all Webb's parts finally joined together into a single observatory for the very first time," Gregory Robinson, the Webb program director at NASA Headquarters in Washington, D.C., said in the same statement. "The engineering team has accomplished a huge step forward, and soon we will be able to see incredible new views of our amazing universe."