NASA’s James Webb Space Telescope (JWST) just took another big step towards completion, as the two halves it was currently in were connected together for the first time at Northrop Grumman’s facilities in Redondo Beach, California.
There is still a lot of work to do before the telescope is ready for launch, sometime in 2021, but the uniting of the two halves is another significant milestone.
As you can see in the photos, the two halves are quite large, and engineers needed to use a crane to life the telescope itself above the already-combined sunshield and spacecraft. Accuracy is of paramount importance, and all primary contact points must be perfectly aligned and seated. The telescope portion contains the mirrors and science instruments.
Although the halves have been physically connected, the electrical connections must still be connected and tested.
“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,” said Bill Ochs, Webb project manager for NASA Goddard Space Flight Center in Greenbelt, Maryland. “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.”
Other testing continues as well, with deployment of the five-layer sunshield next. The sunshield is critical to keep the mirrors and science instruments cold. This is done by blocking infrared light from the Earth, Moon and Sun, and the sunshield must deploy to the correct shape in order to do this.
“This is an exciting time to now see all Webb’s parts finally joined together into a single observatory for the very first time,” said Gregory Robinson, the Webb program director at NASA Headquarters in Washington, D.C. “The engineering team has accomplished a huge step forward and soon we will be able to see incredible new views of our amazing Universe.”
Additional environment and deployment testing must also be done before launch, so the telescope is ready for the various environments it will experience during launch and in orbit.
“Webb should continue based on its extraordinary scientific potential and critical role in maintaining U.S. leadership in astronomy and astrophysics,” said Tom Young, the chair of the review board. “Ensuring every element of Webb functions properly before it gets to space is critical to its success.”
JWST will orbit the Sun about one million miles from Earth. After facing multiple delays, the last in June 2018, it is now scheduled to be launched in 2021 from South America and will essentially be the successor to the Hubble Space Telescope.
The 2021 launch date also adds nearly another billion dollars to the mission cost, with total costs now estimated at $9.66 billion.
Like Hubble, JWST will help to revolutionize our understanding of the Universe, studying objects in our own outer Solar System as well as distant galaxies, stars and exoplanets.
In 2017, the first science targets were chosen for JWST: Jupiter, organic molecules in star-forming clouds and baby galaxies in the distant Universe.
“We were impressed by the high quality of the proposals received. These programmes will not only generate great science, but will also be a unique resource for demonstrating the investigative capabilities of this extraordinary observatory to the worldwide scientific community,” said Ken Sembach, director of the Space Telescope Science Institute (STScI) in Baltimore, Maryland. “We want the research community to be as scientifically productive as possible, as early as possible, which is why I am so pleased to be able to dedicate nearly 500 hours of director’s discretionary time to these early release science observations.”
JWST will also look at Europa and Enceladus, two ocean moons in our Solar System which are thought to be able to possibly support some form of life.
One of the most exciting abilities of JWST is that of analyzing the atmospheres of exoplanets orbiting other stars, including rocky, Earth-sized worlds. JWST will be able to study those atmospheres and search for signs of biosignatures, gases like oxygen and methane that could be evidence for life. Many such rocky planets are being discovered now by other missions like Kepler, but analyzing their atmospheres is difficult with present telescopes. JWST can do that, however. What will it find?
“The more we learn more about our Universe, the more we realize that Webb is critical to answering questions we didn’t even know how to ask when the spacecraft was first designed,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate. “Webb is poised to answer those questions, and is worth the wait. The valuable recommendations of the IRB support our efforts towards mission success; we expect spectacular scientific advances from NASA’s highest science priority.”
More information about JWST is available on the mission website.