Just weeks before the James Webb Space Telescope is finally expected to get to space, Canadian investigators provided a preview of the instruments and the science they expected to see.
Canada’s contributions to the international telescope include a fine guidance sensor that will help the telescope precisely point at objects, and a spectrograph – the Near-Infrared Imager and Slitless Spectrograph – to study objects ranging from exoplanets to galaxies. And as a generational telescope, Webb’s mandate is huge and is expected to include all sorts of observations from objects deep in the universe, to little worlds much closer to home.
As is usual with Canadian contributions, especially of this magnitude (media reports peg the money at a range of $200 million), a collection of government, industry and academia were closely involved in putting together these contributions. The integrated FGS/NIRISS unit was built, tested, and will be maintained by Honeywell. They also received assistance from scientists and engineers from the CSA and Université de Montréal, along with American partners NASA and the Space Telescope Science Institute.
“This is the single highest investment Canada’s ever made into a science instrument for space mission,” Erick Dupuis, CSA’s director of space exploration development, told reporters during a technical briefing Wednesday (Nov. 17). “It’s also one that will provide the most amazing return on investment.”
Scientists often compare the potential of Webb to the revelations allowed by the long-running Hubble Space Telescope. Hubble’s achievements range from helping to chart the expansion of the universe (a Nobel Prize-winning discovery) to providing precise measurements of change concerning everything from solar system planets rarely visited by probes, to distant galactic objects such as the famous “Pillars of Creation” section of the Eagle Nebula.
Hubble also has an advantage of having remained operational for a generation in space. Webb will not have the assistance of astronaut crews to remain working that long, but it does have a location advantage over Hubble in that it will be situated at a Lagrange point. Canada is guaranteed at least a 5 percent share of observing time in thanks for the country’s contributions.
“Canadians are involved in some of the very first science studies,” said Sarah Gallagher, science advisor to the CSA president (and in her other professional duties, Western University’s newly appointed director of Western Space.)
“Some of the first targets they were chosen quite a while ago; we are going to be looking at things like Jupiter, looking at galaxies in the very early universe, and also looking in the areas around massive stars … and there are Canadians who are involved in projects. We’re definitely going to be on the front ranks.”
The FGS development started in 2001 and is based upon hardware that Canada provided for the Far Ultraviolet Spectroscopic Explorer (FUSE) telescope, although the scope of the instrument changed a few times as Webb developed, noted Neil Rowland, an engineering fellow at Honeywell Aerospace.
“FGS has two independent imaging detectors that are fed by common optics, and using these large infrared detector arrays for the guiding function requires some sophisticated image processing, which takes place in the FGS flight software,” he explained.
“The sensor is incredibly precise. It can detect tiny angular displacements of the telescope equivalent to the thickness of a human hair, as seen from a kilometer away. Or if you prefer the equivalent, of seeing somebody blinking in Toronto all the way from Montreal.”
NIRISS will allow astronomers to precisely measure aspects of objects such as their speed or their distance, explained René Doyon, principal investigator at Université de Montréal, in French language remarks. The scientific objectives of NIRISS include first light detection, exoplanet detection and characterization, and exoplanet transit spectroscopy. In other words, information will be obtained about exoplanets as they pass across the face of their parent star.
But the investigators are also expecting Webb will reveal the unexpected; after all, Hubble launched just as the first exoplanets were being investigated and it wasn’t really designed to do so, and yet the observatory has been a contributor to that field of science.
“We’ve built this telescope to be able to do all kinds of different science, and it’s incredibly versatile. It can cover everything from within our own solar system, all the way out to the early universe,” said Chris Willott, project scientist at the National Research Council of Canada’s Herzberg Astronomy and Astrophysics Research Centre.
“We really don’t know what we’re going to see when we turn it on different types of astrophysical objects. In my own research in the very early universe, I really want to know what these galaxies look like a few 100 million years after the Big Bang.”
He added that as capable as Hubble is, investigators have “hit a wall” because Hubble’s capabilities only extend slightly into the infrared. “With Webb, we’re going to go so much further into the infrared, and we have these amazing science instruments that are an improvement on the instrumentation we have onboard Hubble,” Willott added. “We’re going to be able to get much more detailed information on those galaxies that we can get at the moment.”