Astronomers around the world received a great gift this Dec. 25: relief, as NASA’s $10 billion James Webb Space Telescope (JWST) rode safely to space on an Ariane 5 booster from Europe’s Spaceport in Kourou, French Guiana.
The liftoff at 7:20 A.M. EST marked the end of a development full of delays and cost overruns — and the beginning of the telescope’s month-long journey to its destination nearly 1 million miles (1.5 million kilometers) from Earth. Along the way, the telescope will carry out the intricate and risky process of unfolding itself — it was meticulously designed to fold up to fit inside the rocket fairing — and deploying its components and systems.
When it reaches the L2 point, where Earth and the Sun’s gravity cancel out, JWST will keep station as its instruments cool to their working temperatures. Then, in six months, if nothing goes wrong, JWST will begin its ambitious mission to sight the first galaxies and characterize alien worlds.
Delays to the last
JWST originated in a 1996 report put together by a panel of astronomers attempting to plan the successor to the Hubble Space Telescope. It was originally envisioned to launch in 2007 with a price tag of $500 million.
After 14 years of delays and a ballooning price tag that, at times, threatened to swallow NASA’s astrophysics budget whole, JWST has emerged as the most powerful space telescope ever built. It is a joint project between NASA, the European Space Agency, and the Canadian Space Agency. Its 6.5-meter, hexagonal, segmented mirror is shielded from the heat of the Sun by a five-layer sunshield that will allow the telescope to cool to –370°F (–223°C). These frigid conditions will minimize interference at the infrared wavelengths that JWST is designed to observe, allowing the telescope to seek the redshifted light of primordial galaxies and penetrate the dusty shrouds of nebulae to see young stars.
For some astronomers who have much riding on JWST — including observing proposals already accepted and planned — the approaching launch brought a sense of foreboding. This only grew as final delays pushed the launch deeper into the holiday season, adding another layer of stress to a holiday break already thrown into havoc by the omicron variant of COVID-19.
JWST arrived Oct. 12 via cargo ship at the spaceport in French Guiana, on schedule for a Dec. 18 launch date. This slipped to Dec. 22 after an incident during launch preparations, when a band suddenly unclamped itself and jolted the entire observatory, requiring additional checks. Then, a communications problem from the telescope to ground support arose; it was traced to a bad cable and pushed the launch to Dec. 24. Finally, bad weather forced a postponement to the morning of Dec. 25.
Just the beginning
In the end, the successful launch was a moment of holiday cheer for astronomers and space enthusiasts. “Webb is a shining example of the power of what we can accomplish when we dream big,” tweeted U.S. President Joe Biden. “We’ve always known that this project would be a risky endeavor, but with big risk comes big rewards.”
But the euphoria was tempered by the knowledge that the intricate process of unfolding the telescope is yet to come. “[T]his is just the beginning for the Webb mission,” said Gregory L. Robinson, JWST program director, in a statement. “Now we will watch Webb’s highly anticipated and critical 29 days on the edge.”
Perhaps the riskiest steps are the deployment of the sunshield and the mirror wings. But there are many other issues that could doom the observatory. An engineering review identified 344 such weaknesses, known as single point failures — three times as many as a Mars landing, wrote Thomas Zurbuchen, head of NASA’s science division, earlier this year.
“Those who are not worried or even terrified about this are not understanding what we are trying to do,” he added.