The next generational space telescope may finally take flight in 2021. If all goes to plan, the long-anticipated and long-delayed Webb Space Telescope is set to go aloft on Oct. 31, 2021 to start a long journey to a Lagrange point, a gravitationally stable orbit in space around the sun.
Webb’s mission is vast and touches on numerous fields of astronomy, ranging from probing large exoplanet atmospheres to examining galaxies formed early in the universe. The complexity of the flagship $9.8 billion USD ($12.5 billion Canadian) telescope’s construction and testing has added considerable money and time to the mission development, pushing launch estimates back by many years. The last delay in 2020 was also attributed in part to the novel coronavirus pandemic.
Webb’s mandate has been compared to that of the Hubble Space Telescope, which launched nearly 31 years ago and is still going strong – in large part thanks to astronaut crews who performed five servicing missions over the years, concluding the series in 2009. Hubble’s observations have literally spanned the universe, from planets to pulsars – including the Nobel Prize-winning observation that the universe is accelerating in its expansion.
The two telescopes observe in different wavelengths and their mission timelines will overlap, so the Canadian Space Agency (CSA) frames Webb as a successor to Hubble, not a replacement. Also, no astronaut crews will venture to Webb for repairs as it will orbit an incredible 1.5 million km from Earth; Hubble, by comparison, flies only 400 km above our heads.
Canada’s contribution to Webb includes two key components built, tested and maintained by Honeywell. The Fine Guidance Sensor (FGS) helps Webb figure out its position in space and locate, track and lock onto its targets for observations. Additionally, an instrument called NIRISS (Near-Infrared Imager and Slitless Spectograph) will, as its name implies, capture infrared light and spectra from faraway objects, for applications such as studying galaxies, exoplanets and objects that are close together.
CSA entirely funded Canada’s hardware contribution and will continue to fund the efforts of Canadian instrument scientists, who will receive telescope time due to our country’s contributions. The scientific effort includes numerous institutions, led by principal investigator René Doyon, an exoplanet scientist and astronomical instrumentation developer at Université de Montréal.
“Webb is probably one of the most complex machines ever built by humanity. It will revolutionize our understanding of the universe. Almost every chapter of astrophysics will be rewritten after Webb,” Doyon said in an interview.
Doyon said that all telescopes are designed to answer specific science questions, with Webb’s work including examining early galaxies and looking at potentially life-friendly planetary systems.
“However, history shows that the ground-breaking discoveries that these new facilities enable were not predicted,” he added. “For example, Hubble was designed to measure the expansion rate of the universe – the Hubble constant, and it did deliver that. But no one anticipated that Hubble would show that the universe not only is expanding. It’s accelerating, unveiling this strange concept of dark energy that is still mysterious … This is probably what is most exciting about Webb, that it will enable incredible discoveries that we can’t predict now.”
Engineers and scientists alike are fascinated by the potential Webb will offer the astronomy community. California-based Jon Arenberg is working with Canadians on Webb as chief mission architect for science and robotic exploration on Northrop Grumman, which lead the industry team for Webb through development, construction and testing.
“To have the chance to play a part in such a significant project is why I became an engineer,” he said in an interview. “My experience on Webb, ranging from technology development over 15 years ago through the completion of testing, fills me with a sense of awe about what can be achieved when a large team is committed to making amazing happen. Thanks to Webb, we will be able to observe objects and phenomena that no human has ever observed or contemplated.”
One thing that the team greatly anticipates is being able to look at the first billion years after the Big Bang (which took place roughly 13.77 billion years ago). Webb’s infrared eyes allow it to examine objects that are highly “redshifted” or seeing their spectroscopy displaced toward longer wavelengths (the red side of the spectrum). Redshifted objects include those from the early years of the universe, which are highly subject to the universe’s accelerating expansion.
Webb’s work in this area will include studying how galaxy shapes evolve over time, how young galaxies collide and interact with each other, and larger-scale structures such as galaxy clusters – which provide hints as to how dark matter works, said CSA’s Denis Laurent.
“Looking back in time, we will be able to see a lot of structure as galaxies first emerged, and the expansion of the universe,” said Laurent, CSA’s senior program scientist for astronomy.
Webb’s data may also better chart the expansion rate of the universe, Laurent added. There are two different rates charted by the astronomy community (depending on the techniques used) and it is unclear why there is a discrepancy. In 2019, NASA said the chance of the discrepancy being a mere fluke – due to a factor such as “unlucky measurements” – has diminished to 1 in 100,000 after more study.
On a related note, Laurent said he is interested to learn more about the role of dark matter in the expansion of the universe and the large-scale structure of galaxy clusters. “Looking back in time [with Webb], we will be able to see a lot of structure as the universe first emerged,” he said.
And other scientists around the world – including Canadians – are already lining up for time on Webb, as NASA recently issued the first call for proposals for observations. “It was extremely well subscribed and there will be a tremendous amount of interest,” Laurent said. Scientific investigations will include a small period of time where the data is proprietary to the observing team, before opening to the public.
We can get a sense of where Webb’s legacy may lie when we look at the Canadian Astronomical Society / Société Canadienne d’Astronomie (CASCA)’s long-range plan for Canadian astronomy, which was released in December. Webb’s investigations will touch on all four major questions for the community that CASCA outlined as priorities in the coming decade, including the universe’s origins, how stars and galaxies change, the physical limits of the universe, and how planets form and evolve.
Beyond Webb, the 209-page CASCA report makes many recommendations for further investment in current and future Canadian astronomical observatories and participation in international observatories. Some of the wider-field observatories cited in this report will complement Webb in that they can provide valuable context to the close-up views Webb’s 6.5-meter mirror will capture, Laurent said.
“Canadian research is really appreciated internationally, with a lot of research and capabilities in Canada done at all the major universities in the world,” Laurent said. “We’re near the top of the list in number of [scientific] papers produced per capita, per citation, and extremely well-established. In order to maintain that, we need to keep having access to these other major [astronomy] facilities, whether ground-based or space-based.”
Northrop’s Arenberg pointed to numerous innovations on Webb that will be deployed – literally, in some cases – in the first few months of its mission, such as unfolding its mirror in space and making its way to the Lagrange point during its commissioning period. The innovation, he added, will continue throughout Webb’s mission, which could last for a decade if all goes well.
“Webb’s legacy is one of boldness,” he said. “Through imagination, ingenuity, dedication and leveraging the power of teamwork, unimaginable innovation and discovery emerges. I truly believe that Webb and its mission will inspire future scientists, engineers and dreamers for generations to come.