"#NASAWebb is fully deployed! With the successful deployment & latching of our last mirror wing, that's: 50 major deployments, complete. 178 pins, released. 20+ years of work, realized," the agency tweeted. "Next to #UnfoldTheUniverse: traveling out to our orbital destination of Lagrange point 2!"
"I’m emotional about it. What an amazing milestone. We see that beautiful pattern out there in the sky now," Thomas Zurbuchen, NASA’s science missions chief, remarked.
Early Saturday morning, NASA wrote in a blog post that the Webb mission operations team had given the "go-ahead" to move forward with the extension of its starboard primary mirror panel – the final step in the process.
"This is the last of the major deployments on the observatory, and its completion will set the stage for the remaining five and a half months of commissioning, which consist of settling into stable operating temperature, aligning the mirrors and calibrating the science instruments," it said.
According to the Goddard Space Flight Center's JWST timeline, the next step will be a multi-day, multi-step mission to activate and move each of Webb's 18 primary mirror segments out of their launch configuration.
The $10 billion observatory – a joint effort of NASA, the European Space Agency and the Canadian Space Agency – launched from Earth on Christmas Day and has a mission duration of up to 10 years.
Webb has a million-mile journey to reach its destination – in another two weeks – where it can orbit the sun in line with the Earth.
The trip takes the JWST to the second Lagrange (L2) point, a point that enables continuous communications with Webb through the Deep Space Network.
The telescope will "explore every phase of cosmic history," according to NASA, peering back 13.7 billion years.
"Webb will reveal new and unexpected discoveries and help humanity understand the origins of the universe and our place in it," it wrote.
"The promise of Webb is not what we know we will discover; it’s what we don’t yet understand or can’t yet fathom about our universe," NASA Administration Bill Nelson said in a statement last month. "I can’t wait to see what it uncovers!"
There are another five-and-a-half months of set-up activities on the docket before Webb will be ready to deliver its first images.
The Associated Press contributed to this report.