Webb’s FGS and NIRISS Instrument Are Ready for Launch

We continue to explore Webb’s instrumentation this week, highlighting the Canadian contributions to the mission. As you’ll see, the Near-Infrared Imager and Slitless Spectrograph (NIRISS) instrument is ideally suited for studying two of Webb’s scientific themes. Scientists will use NIRISS to take advantage of the natural phenomenon of the atmospheric transmission of transiting exoplanets and the gravitational lensing of galaxy clusters, to help us learn more about these intriguing objects. René Doyon, scientific lead for NIRISS, and his colleagues help us understand NIRISS’s capabilities:

“NIRISS is one of two contributions to the Webb mission from the Canadian Space Agency and other Canadian partners. Its development over two decades has been full of twists and turns, but we are very proud with the instrument that resulted from all our work!

Canada's Fine Guidance Sensor (FGS) and Near-Infrared Imager and Slitless Spectrograph (NIRISS) at NASA's Goddard Space Flight Center.
Canada’s Fine Guidance Sensor (FGS) and Near-Infrared Imager and Slitless Spectrograph (NIRISS) at NASA’s Goddard Space Flight Center. (Credit: NASA)

“NIRISS is coupled with Webb’s Fine Guidance Sensor (FGS) within a single module about the size of your average washing machine. FGS is one of several of Webb’s mission-critical sub-systems whose function is to keep the observatory aimed at its target with exquisite accuracy to enable the sharpest possible images. FGS will be capable of detecting a tiny angular displacement of the telescope equivalent to the thickness of a human hair as seen from one kilometer away. NIRISS is a scientific instrument with several observing modes that will allow astronomers to study a multitude of different types of celestial targets to reach many of Webb’s scientific objectives.

“With incredibly high-precision spectroscopy, NIRISS will study the chemical composition of the atmospheres of exoplanets, searching for conditions that may be favorable for life. As the light from a distant star passes through the tenuous atmosphere of its transiting exoplanet, a very small fraction of the light is absorbed by atoms and molecules. This “molecular fingerprint” of the atmosphere tells us about the gases and atmospheric conditions on these alien worlds.

“In another observing mode, NIRISS will capture the spectra of over a thousand galaxies in one shot to map extremely faint and distant galaxies as they appeared shortly after the big bang. When they were first formed a few hundred million years after the start of the universe, these galaxies shone very brightly in ultraviolet and blue light. As their light travelled across an expanding universe, it was stretched and redshifted into infrared light, making a near-infrared instrument like NIRISS the perfect tool to study the nature of these very early galaxies.

“NIRISS will also use a clever technique called Aperture Masking Interferometry to directly image celestial objects that are very close together in the sky. Solar systems being born, brown dwarfs, and exoplanets very close to their parent stars will be captured by the instrument to better understand how these objects form and evolve over time.

“NIRISS, along with Webb’s other scientific instruments, will truly open a new window on the cosmos and unfold the universe as we have never seen it before. After many, many years of imagining, developing, constructing, testing, and waiting, NIRISS and FGS are ready for launch! On behalf of the Canadian Space Agency, Honeywell Aerospace, the National Research Council of Canada, the Université de Montréal, and the entire NIRISS science team, we cannot overstate how excited we are for this milestone moment to finally be here!”

—René Doyon, Nathalie Ouellette (Université de Montréal), and Chris Willott (NRC-Herzberg)

By Jonathan Gardner, Webb deputy senior project scientist, NASA’s Goddard Space Flight Center

And Alexandra Lockwood, project scientist for Webb science communications, Space Telescope Science Institute

Webb’s NIRSpec Instrument Is Ready for its Ride to Space

As progress continues in Kourou, we check in with another one of Webb’s instruments, the Near-Infrared Spectrograph (NIRSpec), and its scientific lead, Pierre Ferruit:

“It was more than 20 years ago that the European Space Agency (ESA) teamed up with NASA and the Canadian Space Agency to build the amazing James Webb Space Telescope! The NIRSpec instrument is one of the four elements contributed by ESA to the Webb mission.

“NIRSpec was designed and built for ESA by a consortium of European industrial companies led by Airbus Defence and Space, Germany, with some components provided by NASA, making it a truly international effort, just like Webb itself!

“Measuring approximately 1.9 m x 1.3 m x 0.7 m, NIRSpec is the largest instrument on board Webb. Yet it weighs less than 220 kg. Built to withstand the tremors of a rocket launch and the rigors of space, it is a marvel of technology and engineering like many things in Webb. Its optical bench and most of its mirrors are made of an extremely hard and stable ceramic material called silicon carbide. European industry has become a master of the craft of manufacturing and using this very special material for building space telescopes and instruments like NIRSpec.

The final taping of the protective cover is applied and the James Webb Space Telescope NIRSpec instrument is in its final flight configuration and ready to go back into the Integrated Science Instrument Module.
Credit: NASA/Chris Gunn
The flight James Webb Space Telescope NIRSpec instrument, undergoing integration.
Credit: Astrium/NIRSpec

“Now, let’s talk a little bit about science with NIRSpec and in particular about ‘spectra.’ A key role of NIRSpec in the Webb mission is to allow scientists to study in greater detail the properties of faint galaxies detected in images such as those from NIRCam. For that, NIRSpec will split the infrared light from these galaxies into different shades of infrared and generate what we call spectra. Analysis of these spectra will tell us how distant these galaxies are, what type of stars they contain, what is the relative abundance of life-giving elements such as oxygen and carbon in their interstellar gas, and much more. Each spectrum is a small treasure trove of information that will help scientists understand how the first stars and galaxies formed when the universe was only a few hundred million years old!

“Since this is only one example of what NIRSpec can do, you will understand how excited we are now that Webb, with NIRSpec cozily installed at the back of the primary mirror, is being prepared for launch. After rigorous tests on Earth, NIRSpec is ready! Go Ariane, go!”

—Pierre Ferruit, ESA Webb project scientist, and the NIRSpec team

By Jonathan Gardner, Webb deputy senior project scientist, NASA’s Goddard Space Flight Center

And Alexandra Lockwood, project scientist for Webb science communications, Space Telescope Science Institute

Webb’s NIRCam Instrument Is Ready for Launch

In Kourou, Webb went through a thorough checkout called the Comprehensive Systems Test (#6). The test included turning on all of the room-temperature electronics and a test of the mirror actuators that will be used to align the mirror segments during commissioning. The tests went very well, and the next time we move the mirrors, they will be in space! The Near-Infrared Camera (NIRCam) plays a critical role in that process, and Marcia Rieke, scientific lead for the instrument at the University of Arizona, shares her look ahead for the next several months:

“The 20-year journey that has taken NIRCam, the near-infrared camera for the James Webb Space Telescope, from a concept to reality will culminate on December 18 with a ride on an Ariane 5 rocket. One of Webb’s major science goals is the detection of the first galaxies to form after the big bang. NIRCam was built with this goal in mind, and the NIRCam team is using much of their observing time to achieve this goal. During the last few years the team has built on Hubble discoveries to simulate what Webb will see. The team can hardly wait to compare the real data to the simulation—which will tell us immediately what the real universe has produced.

Simulation of the NIRCam deep survey images that will be used to search for the first galaxies
Simulation of the NIRCam deep survey images that will be used to search for the first galaxies. Credit: NIRCam instrument team

“The launch will be scary, as rocket launches always are for those who have a delicate instrument atop the rocket, but confidence is very high that the telescope and instruments will reach orbit safely. And NIRCam is critical for what happens in the months after we get there. About 35 days after launch will be needed for NIRCam and the telescope to cool enough to first turn NIRCam on. The excitement will continue to build as NIRCam takes the data used to corral and align the 18 segments of the primary mirror. The segments will be higgledy-piggledy when they are lifted off the mounts used for safe stowage against the launch motions. Modeling the detailed motions of spacecraft parts during launch is essentially impossible, so the NIRCam data will show the engineers where the mirror segments are located. Careful measurement of the 18 star images, the same star seen reflected off each of the mirror segments, will provide the data needed to generate the commands for moving the mirrors into alignment. These data will not be valuable scientifically, but the NIRCam team will be jumping for joy to see them as they will be the first indications that the telescope and NIRCam can work together. After celebrating the first focused star data, the NIRCam team will have to wait several more months before the telescope and cameras are ready to make the observations showing the most distant galaxies. But after 20 years, waiting a few months when one knows that everything is working shouldn’t be too bad.”

—Marcia Rieke, principal investigator for the NIRCam instrument and professor of astronomy, University of Arizona

By Jonathan Gardner, Webb deputy senior project scientist, NASA’s Goddard Space Flight Center

And Alexandra Lockwood, project scientist for Webb science communications, Space Telescope Science Institute

The Journey to Kourou

Congratulations to Arianespace on last weekend’s launch of two communications satellites into geostationary transfer orbit aboard an Ariane 5. The launch pad is now cleared to receive Webb, which has arrived at Europe’s Spaceport in Kourou and has begun preparations for its December launch. To hear more about the journey to French Guiana, and the anticipated-yet-still-surprisingly-emotional reaction it has imparted, here is the mission’s deputy senior project scientist, Jonathan Gardner:

“As I watched the video of the Webb telescope being loaded into the hull of the MN Colibri ship and heading out to sea, I found myself almost in tears. I thought, ‘If I am feeling this emotional now, what will launch be like?’

“I’ve worked on the Webb project since 2002, almost 20 years. At the time that I was first walking my children to kindergarten, I helped to write down the science goals that were used to guide the design of Webb. Now, as my youngest child applies to college, I can read the proposals that were selected for the first year of Webb science. Some of the details have changed, but the themes are the same: distant galaxies, forming stars, and planets. The 13.8-billion-year journey from the primordial material of the big bang to planets with the building blocks of life.

“Webb is a product of the world, with cameras from Europe and Canada, and contributions from most U.S. states. The components of Webb have traveled before; the complex 15-stage journey of the mirrors is now complete. Or, almost complete; Webb still has to make the giant leap into space atop a massive Ariane 5 rocket.

Webb is loaded onto the MN Colibri
Credit: Mike McClare, NASA’s Goddard Space Flight Center

“After finishing the decade-long assembly and testing process, Webb was packed into the STTARS transport container. With Webb nestled safe in its cushioned support structure and dry-nitrogen climate-controlled environment, the truck driver reached a maximum speed of 7 miles per hour on the middle-of-the-night journey from a Northrop Grumman clean room to the port at Seal Beach. Leaving on September 26, with Webb loaded into its cargo hold, the MN Colibri sailed along Baja California and reached the Panama Canal.

The MN Colibri passes through the Panama Canal
Credit: The Panama Canal Authority

“Webb took 8 hours to traverse through 3 locks of the Canal and entered the Atlantic Ocean on October 6. After continuing around the South American coast, Webb arrived in Kourou on October 12, and was unloaded amid the palm trees and tropical birds of French Guiana.

In this photo, the James Webb Space Telescope is driven to Guiana Space Centre from the port. It was shipped from California, through the Panama Canal, to French Guiana, where it will launch. The launch vehicle and launch site are part of the European Space Agency's contribution to the mission.
Credit: ESA/CNES/Arianespace

“Webb has now moved into the Arianespace processing facility. After a few final electrical tests, insulation closeouts, and the critical spacecraft fueling, Webb will be lifted atop an Ariane 5 and launched. A year from now, my child will be starting college and exploring new environments, and so will Webb. Webb will be sending a flood of astronomical data back to Earth – helping us to understand the journey of the universe. Although sometimes there can be tears when one stage of a journey ends and another begins, we are all three ready for the future: my child, myself, and the Webb telescope.”

—Jonathan Gardner, Webb deputy senior project scientist

By Jonathan Gardner, Webb deputy senior project scientist, NASA’s Goddard Space Flight Center

And Alexandra Lockwood, project scientist for Webb science communications, Space Telescope Science Institute

Introducing the Webb Blog

This is it! It is less than two months until the Webb telescope finally launches, and we couldn’t be more excited. Webb is NASA’s next flagship observatory and a technological marvel, more than twenty years in the making. It has just arrived in Kourou, French Guiana – home to Europe’s Spaceport facility and our upcoming launch site. (More on that next week, including some amazing photos and video footage!)

We are starting a blog to keep you abreast of what is happening during the telescope’s launch and commissioning timeframe. The first science from the observatory won’t be available until next summer, but there are many exciting things along the way. We’ll also use this space to hear firsthand from some of the mission’s top scientists and engineers about the technical processes that are happening, their experiences with the mission, and the exciting discoveries that await us!

To begin, we asked the mission’s senior project scientist and Nobel laureate, John Mather, to reflect upon the mission that will define the next decade of astronomy:

“On behalf of all scientists and all curious people everywhere, thank you to the team who made the Webb telescope possible! It represents decades of work by over 10,000 of us, putting our hearts and minds and fingers together through troubles, nights, weekends, and COVID.

“Now we’re near launch, and everyone wants to know if I’m worried – will it work? My opinion has no effect on the hardware, but we did what it takes to win. We sketched, we argued, we worried, we analyzed, we made a plan, we wrote down everything, we made checklists, we built the parts, we put them together, we tested as though our lives depend on it. We have backup electronic systems for everything where we can. Everyone on the team knows how much this mission matters to the world.

“Our scientific colleagues are ready to go. We’ve decided where we’re going to look for the whole first year of scientific observations. We’ll be hunting for the first objects that grew out of the primordial big bang material, we’ll be looking at distant galaxies to see back in time, we’ll be looking inside dust clouds to see stars and planets being born today, we’ll be looking at planets around other stars to see if they have atmospheres, and we’ll be looking close to home at everything in the solar system from Mars on out.

“But before we do that, we have to set up the equipment. We’ve got an hour-by-hour plan, and it takes 6 months. First, we unfold the observatory by remote command, then we wait for its plastic sunshield to dry out, then we let the telescope cool down, then we focus it, then finally we check out the four instruments. They come from the U.S., Europe, and Canada, and they will make images and spectra, spreading out the light into rainbows that tell us what’s happening inside the stars and galaxies – what’s their chemistry, how hot are they, how are they moving? The data will come back by radio to the computers and scientists around the world. We’ll be asking and trying to answer: Where did we come from? How is life possible here on Earth?

“It will be worth the wait.”

—John Mather, Webb senior project scientist


By Alexandra Lockwood, project scientist for Webb science communications, Space Telescope Science Institute

And Jonathan Gardner, Webb deputy senior project scientist, NASA’s Goddard Space Flight Center