The launch of NASA’s next-generation observatory, the James Webb Space Telescope, is less than a month away. The $9.8 billion Webb has overcome years of technological delays, financial challenges, and a pandemic to reach its scheduled launch date in French Guiana on December 18.
Webb’s scientific objective will be extensive, ranging from investigating tiny planets in our solar system to scanning the furthest reaches of the universe. “We’re going to look at everything that we can see in the cosmos,” Webb senior project scientist John Mather told reporters during a news briefing on Wednesday (November 18). Webb will go to a remote location known as a Lagrange point, a gravitationally stable region between two celestial bodies, around 1 million miles from Earth as the successor to NASA’s venerable Hubble Space Telescope.
Webb will be there about a month following the launch. The observatory will next go through a six-month commissioning stage that will entail several crucial milestones, such as unfolding its complex mirror and ensuring that all instruments are operational before Webb opens its eyes.
“The primary mirror was too large to fit in a rocket at six and a half meters, so we built it to unfurl in orbit,” Lee Feinberg, Webb optical telescope element manager at Goddard, explained at today’s briefing. “Because it does not fold like a drop leaf table, we required segmented mirrors.”
The mirrors, according to Feinberg, would initially function as 18 different telescopes, and it will take algorithms many months to perfectly align them to an accuracy of one-5,000th the diameter of a human hair. And that’s presuming the telescope correctly unfolds them all, which NASA has stated is one of the most challenging technological challenges Webb will confront.
Webb researchers are keeping quiet about what the telescope will focus on initially when it is completed. However, hints may be found in the “early release science projects” list that will emphasize Webb’s core research in the study of planets, the solar system, galaxies, black holes, stellar physics, and star populations. The initial photographs will be in great demand since mission scientists claim the resolution will be 100 times higher than Hubble’s and will disclose considerably more in infrared (or heat) wavelengths than the older telescope can.
While the initial targets have yet to be determined, Webb will soon start turning back the clock on cosmic observations, offering a peek at the universe as it was only 100 million years after the Big Bang. According to Mather, Webb will cover a vacuum left by Hubble, which has let astronomers look back 400 million years after the Big Bang.
Canada is supplying a precision guidance sensor for guiding Webb, as well as a spectrograph to study exoplanets and galaxies. For its contribution, the country is promised a 5% share of observation time. One Canadian team will investigate the atmospheres of exoplanets to identify their compositions and temperatures. “Another Canadian team will investigate some of the first galaxies to develop, as well as galaxies grouped in tight communities known as clusters,” said Sarah Gallagher.
What intrigues scientists the most is the unpredictability of what Webb will disclose, and even a cursory look at Hubble’s past gives plenty of examples. No one knew about the presence of dark energy, a significant impact on cosmic expansion, when Hubble was launched in April 1990. Exoplanets had yet to be proven, but we now know about thousands.
Hubble also discovered some surprises closer to Earth, such as when it assisted NASA’s Unexpected Horizons Pluto mission in steering appropriately around some new findings.