James Webb Space Telescope

On Saturday, Dec. 11, NASA’s James Webb Space Telescope was secured on top of the Ariane 5 rocket that will launch it to space from Europe’s Spaceport in French Guiana.

After its arrival in the final assembly building, Webb was slowly hoisted nearly 130 feet and then perfectly aligned on top of the Ariane 5, after which technicians bolted Webb’s launch vehicle adapter down to the rocket.

This whole process was performed under strict safety and cleanliness policies, as it was one of the most delicate operations during the entire launch campaign for Webb. A custom ‘shower curtain,’ already installed between the two platforms where technicians worked to connect Webb to its launch vehicle, served as the walls of a clean room to keep the observatory dirt-free.

The next step ahead is to encapsulate Webb inside the Ariane 5’s specially adapted fairing.

Webb will be the largest, most powerful telescope ever launched into space. As part of an international collaboration agreement, the European Space Agency (ESA) is providing the telescope’s launch services using the Ariane 5 launch vehicle. Working with partners, ESA was responsible for the procurement of the launch services by Arianespace and for the development and qualification of Ariane 5 adaptations for the Webb mission.

Webb is an international partnership between NASA, ESA, and the Canadian Space Agency.

Find out more about Webb at: https://webb.nasa.gov.

By Thaddeus Cesari, Webb science writer, NASA’s Goddard Space Flight Center, Greenbelt, Md.

Two weeks until launch! Things are moving forward in Kourou, and so we check in with the two leads (one from the U.S., one from the U.K.) of the final instrument in Webb’s suite:

“Webb’s Mid-Infrared Instrument (MIRI) is special – in the wavelengths it covers, the science that enables, its technology challenges, and in the way it was built.

“With the other three instruments, Webb observes wavelengths up to 5 microns. Adding wavelengths out to 28.5 microns with MIRI really increases its range of science. This includes everything from studying protostars and their surrounding protoplanetary disks, the energy balance of exoplanets, mass loss from evolved stars, circumnuclear tori around the central black holes in active galactic nuclei, and a lot more.

“The universe is relatively unexplored at mid-infrared wavelengths. Since anything at room temperature emits mid-infrared light, infrared astronomers working with ground-based telescopes peer through the huge foreground infrared emission of the telescope and atmosphere. With perseverance, some interesting mid-infrared results have been obtained from ground-based telescopes, but the limitations are severe.

“Dramatic results in the mid-infrared have come from telescopes in the vacuum of space, where they are cooled to cryogenic temperatures to eliminate their emission and are clear of Earth’s atmosphere. This brings big technical challenges. To keep the ice off the telescope before it was launched, the first infrared telescopes in space were built into thermos flasks, or Dewars, with thick walls to hold a vacuum. This meant that these telescopes had to be small, around a tenth the diameter of Webb. Despite their small size, these telescopes were very sensitive and have surveyed the entire sky as well as conducted pioneering studies of individual sources.

“Webb is built on a scale approaching the largest telescopes on the ground, and it will be cold enough to provide the full potential for the mid-infrared. The sensitivity gains and the image clarity will both be nearly a factor of 100 better than ever before. This was so exciting that ten European countries plus the United States pooled resources to make MIRI possible. The National Space Agencies of these ten European countries committed additional funding, beyond their ESA membership, specifically to build MIRI and enable its compelling science.

“While Webb provides the kind of capabilities in the mid-infrared that have only been dreamt of since the beginnings of infrared astronomy, we could only fit a single mid-infrared instrument into Webb and the available international resources. So, we designed the MIRI optics to cover almost everything – imaging, low- and medium-resolution spectroscopy, and high-contrast coronagraphy. About a third of the space for MIRI is empty to allow for long, thermally-isolating hexapod legs. MIRI includes a helium-filled closed-cycle cryogenic refrigerator to bring it to an operating temperature 33 degrees colder than the rest of Webb, reaching less than 7 degrees above absolute zero.

“Our multinational, transatlantic team has pulled together for more than two decades, with both exciting additions and painful losses, to provide Webb and the astronomical community with a mid-infrared instrument. Finally, the moment has arrived when the scientific results will reward everyone who has contributed. The instrument is ready, our cooler is full of helium and connected up, and the team is raring to go.”

—George Rieke, professor of astronomy at the University of Arizona, and Gillian Wright, director of the UK Astronomy Centre

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

On Dec. 7, NASA’s James Webb Space Telescope was transferred to the final assembly building at Europe’s Spaceport in French Guiana to meet its Ariane 5 launch vehicle.

Stowed inside a special transport container and mobile clean room, Webb’s vitals were meticulously monitored throughout the entire process of moving between buildings.

The Ariane 5 rocket Webb will ride to space was moved to the same building on Nov. 29. Here, adjustable platforms allow engineers to access the launch vehicle and its payload.

The next steps ahead are to safely lift Webb to an upper platform which has been prepared so that Webb can be connected to the Ariane 5’s upper stage. After being connected to the rocket, technicians will move forward to encapsulate Webb inside Ariane 5’s specially adapted fairing.

In preparation for a Dec. 22 launch, ground teams have already successfully completed the delicate operation of loading the spacecraft with the propellant it will use to steer itself while in space.

Webb will be the largest, most powerful telescope ever launched into space. As part of an international collaboration agreement, ESA (the European Space Agency) is providing the telescope’s launch service. Working with partners, ESA was responsible for the development and qualification of Ariane 5 adaptations for the Webb mission.

Webb is an international partnership between NASA, ESA and the Canadian Space Agency (CSA).

Find out more about Webb here: https://jwst.nasa.gov/content/webbLaunch/index.html

By Thaddeus Cesari, Webb science writer, NASA’s Goddard Space Flight Center, Greenbelt, Md.

Editor’s Note, Dec. 8, 2021: This post has been updated with more accurate fueling figures.

In preparation for launch later this month, ground teams have successfully completed the delicate operation of loading the James Webb Space Telescope with the propellant it will use to steer itself while in space.

In order to make critical course corrections shortly after launch, to maintain its prescribed orbit nearly 1 million miles from Earth, and to repoint the observatory and manage its momentum during operations, Webb was built with a total of 12 rocket thrusters. These rocket thrusters use either hydrazine fuel or a special mixture of hydrazine fuel and dinitrogen tetroxide oxidizer.

To safely handle these extremely toxic propellants, Webb was moved to the fueling section of the Ariane payload preparation facility at Europe’s Spaceport in French Guiana. Specialists wore Self-Contained Atmospheric Protective Ensemble, or “SCAPE,” suits while loading the observatory. The nearly 10-day procedure began Nov. 25.

Webb’s spacecraft bus, built by Northrop Grumman, was filled with 369 pounds (168 kilograms) of hydrazine fuel and 292 pounds (133 kilograms) of dinitrogen tetroxide oxidizer. Both fuel and oxidizer will be used together to maximize power for the biggest “burns” by Webb’s Secondary Combustion Augmented Thrusters, which are for mid-course corrections and inserting into L2 orbit, as well as for orbit maintenance around L2 during the mission. However, hydrazine alone will be used for the small “burns” by Webb’s tiny precision Monopropellant Reaction Engine thrusters, which are used for large-angle repointing and for managing spacecraft momentum. The fuel loading system was formally disconnected Dec. 3, followed by inspections and closeouts that concluded over the weekend.

Combined operations between the Arianespace and NASA teams preparing Webb and its Ariane 5 rocket are now set to begin. The next large milestones for the joint teams will be to move Webb to the Bâtiment d’Assemblage Final (BAF), or Final Assembly Building; place it atop its rocket; and encapsulate it inside its protective fairing. With final closeouts complete, the full stack of rocket and payload atop its mobile launch platform will be rolled out of the BAF to the launch pad, two days before its scheduled Dec. 22 launch.

By Thaddeus Cesari, Webb science writer, NASA’s Goddard Space Flight Center, Greenbelt, Md.

On Wednesday, Nov. 17, NASA Headquarters held its final review for the mission prior to launch. A week later, on Nov. 24, a review committee approved Webb’s transition to the next stage in its preparations for launch. This week we’ve asked NASA’s Randy Kimble, Webb’s integration, test, and commissioning project scientist, to tell us how things are going at the launch site:

“The loading of propellants into the Webb observatory is complete at the Arianespace launch facilities in Kourou, French Guiana. This is an important step in the path toward launch.

“The vast majority of the launch energy required to send Webb to its operating orbit around the Sun-Earth Lagrange point L2 will be provided by the massive Ariane 5 rocket. Nevertheless, the observatory carries propellants of its own. After being released from the launcher, Webb will use its own system of small rocket thrusters to fine-tune its approach to its final halo orbit around the L2 point (illustrated below), where the telescope and instruments will cool in the shade of the enormous sunshield, protected from the heat of the Sun, Earth, and Moon. Mid-Course Correction maneuvers for refining the trajectory are planned (nominally) for 12.5 hours and 2.5 days after launch, with a third one month later, to ease Webb into its L2 orbit. Those same thrusters will be used periodically throughout the mission to maintain that orbit, with small maneuvers called ‘station keeping.’

“A second set of smaller thrusters on the observatory compensate for momentum buildup caused by the pressure of solar radiation onto the large area of the sunshield. Although Webb is designed to keep that pressure well balanced, angular momentum builds up as the telescope points at different targets, so occasional, small momentum-unloading maneuvers are required to keep the observatory’s reaction wheels within their proper operating ranges. Reaction wheels are flywheels in the Webb spacecraft that help keep the payload’s orientation stable.

“Propellant loading was the final major operation for the observatory itself, before it moves to the Final Assembly Building (BAF is the French acronym) for integration with the Ariane 5 launch vehicle.

“One special aspect of processing the Webb observatory at the launch site is the need to keep it clean. Unlike Hubble, whose telescope is enclosed in a protective tube, Webb can operate successfully with just the shade of the sunshield to protect it in space. While it is subject to the air on Earth, the environment around the telescope must be kept as clean as possible. This ensures that Webb’s mirrors and sunshield are not contaminated with small particulates or molecular films, both of which could reduce the observatory’s sensitivity. The NASA, ESA (European Space Agency), Arianespace, and French space agency (Centre National d’Etudes Spatiales) teams have cooperated very closely to custom-clean the launch facilities to Webb’s demanding requirements. NASA’s Goddard Space Flight Center has also provided portable HEPA filter walls to augment the contamination control of the airflow near the payload. Goddard contamination engineers Eve Wooldridge and Alan Abeel have reported excellent results from the joint contamination control efforts for the roughly seven weeks Webb has been in Kourou so far. They note that continued vigilance is required for the remainder of the ground processing flow, as the most challenging facilities are still ahead.

“From Eve and Alan, ‘Our NASA contamination control engineers and technicians have transformed facilities that are not designed for scientific spacecraft into well-controlled clean rooms not just with HEPA filters, but by covering, cleaning, removing, bagging, and sealing over items incompatible with Webb’s stringent cleanliness requirements, and then cleaning every surface daily.’ The launch site facilities that Webb has encountered so far have all performed well, thanks to these efforts. The next challenge is to transform the facilities in the BAF (which opens huge doors for the rockets and spacecraft), where Webb will be integrated with the rocket and then encapsulated. This can be done because of the excellent team Eve and Alan are so fortunate to work with. ‘We maintain that this is not just the largest contamination control team in the world doing this type of work; it is the best and most hard-working. They have cheerfully worked long days, six days a week, and have proven to be a strong morale-booster for the entire launch campaign team. While we all look forward to launching Webb and getting home to our families, we know we will miss each other and this amazing time in Kourou very much.’

“As Webb prepares to move to the final steps of ground integration, there are no more planned major ground tests of the payload – only minimal electrical checks. The Comprehensive Systems Test that was performed in late October to confirm the observatory’s health after arriving at the launch site represented the culmination of many years of testing. The successful completion of that major ground test put members of the Webb team who had traveled to Kourou in a reflective mood:

“Macarena Garcia Marin, ESA’s instrument and calibration scientist for Webb’s Mid-Infrared Instrument (MIRI), noted with pride the ‘can-do’ attitude and the wonderful feeling of camaraderie among the team that was required to get through years of often-grueling test campaigns. She was also thrilled by the opportunity to see a ‘sneak preview’ of the Webb launch, having viewed the most recent Ariane 5 launch (VA255, on October 23) from a distance of three miles away – ‘Breathtaking!’

“Scott Lambros, Webb instrument systems manager at Goddard, reported mixed feelings as ground testing of the observatory drew to a close: ‘Strangely enough, it’s sad to see the observatory going away – we’ve been working with it so long now, it’s like saying goodbye to a friend. It’s also sad that many of the wonderful people I’ve been working with in the last 19 years soon will be going in different directions. On the other hand, I am extremely excited to see Webb ready for launch and prepared to fulfill its scientific purpose out at L2.’

“As are we all.”

—Randy Kimble, Webb integration, test, and commissioning project scientist, Goddard

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

As we approach the launch of our incredible mission, we asked people across the mission to share why they are grateful for Webb.

I am thankful for…

“the wonderful engineers, project leaders, and skilled technicians who crafted the amazing Webb machine that will enable us to fulfill our science vision!”

—Heidi B. Hammel, Webb interdisciplinary scientist, Association of Universities for Research in Astronomy (AURA)

“having had the chance of taking part in a piece of history. It will be certainly the most complex and ambitious program I will collaborate with in my lifetime scientifically and technically, but also, and maybe more importantly, the most rewarding as a person with human relationships built over the long journey with all the colleagues and friends in the JWST project.”

—Jose Lorenzo Alvarez, former MIRI payload manager, ESA (European Space Agency)

“the incredible opportunity to work on an engineering marvel and a piece of history. The mentors I’ve had along the way and being part of an amazing team of people.”

—Yi Wang, Webb launch systems integration engineer, Northrop Grumman

“the JWST project recognizing planetary science as an essential science priority and working to enable moving target tracking so we can observe solar system objects.”

—Stefanie Milam, Webb deputy project scientist for planetary science, NASA’s Goddard Space Flight Center

“being able to meet people from around the world and talk to them about the promise and anticipated discoveries of the James Webb Space Telescope.”

—Peter Sooy, outreach and communications specialist, ASRC Federal System Solutions

“the people I’ve been working with during cooler integration and test and will be working with during commissioning the cooler after launch.”

—Bret Naylor, MIRI cooler commissioning lead, NASA’s Jet Propulsion Laboratory

“the team leaders who have taught me so much. I am thankful to have met and become friends with so many folks. I pray for the team members who are no longer with us. We all played an important part of making James Webb a success.”

—Shirley Paul, quality assurance engineer, Genesis Engineering Solutions

“the opportunity to be part of a project so big, that it’s literally ‘out of this world.’ I couldn’t have imagined one day working alongside incredible people, for a NASA mission, and that I—with my small part on social media—would be part of this group.”

—Jaclyn Barrientes, senior social media specialist, Space Telescope Science Institute (STScI)

“being part of the JWST project and having seen time and again how people from all over the world get together and work collaboratively to overcome any challenge, from engineering or scientific problems to a world pandemic—always finding new solutions to push through and complete the mission!”

—Giovanna Giardino, instrument scientist, ESA

“being hired for this job just a year before JWST launch—it was a dream come true as I had been waiting for an opportunity to be part of JWST ever since I saw JWST mirrors at [Goddard] about seven years ago when I was just a master’s student.”

—Nimisha Kumari, ESA/AURA astronomer, STScI

“the two decades of camaraderie, friendship, dedication, and perseverance shared with the JWST family bringing the dream of this great observatory to reality.”

—John Johnston, OTIS deputy systems engineer, Goddard

“being part of a mission that I’m sure will change the way we understand the universe. I feel certain we are in for some surprises!  I’m also thankful for getting to work with some amazing people on this telescope over the years.”

—Amber Straughn, deputy project scientist for communications, Goddard

“everyone who showed up every day and gave J-Dub their all each and every day. We sacrificed a lot of weekends and long days over the years. There aren’t many other jobs where you will work on something for so long and not know you did a good job until a later moment in time. But I do know we gave it our all and left everything out there on the field (clean room). And that’s all you can do.”

—Colin Burt, mission systems engineering—sunshield, Heliospace

“my families, both home and NASA, for their years of support over the life of this mission.”

—Eric Smith, Webb program scientist, NASA Headquarters

From our Webb family to yours…happy Thanksgiving!

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

Engineering teams have completed additional testing confirming NASA’s James Webb Space Telescope is ready for flight, and launch preparations are resuming toward Webb’s target launch date of Wednesday, Dec. 22, at 7:20 a.m. EST.

Additional testing was conducted this week to ensure the observatory’s health following an incident that occurred when the release of a clamp band caused a vibration throughout the observatory.

On Wednesday, Nov. 24, engineering teams completed these tests, and a NASA-led anomaly review board concluded no observatory components were damaged in the incident. A “consent to fuel” review was held, and NASA gave approval to begin fueling the observatory. Fueling operations will begin Thursday, Nov. 25, and will take about 10 days.

The Webb Space Telescope is an international partnership with the European and Canadian space agencies. It will explore every phase of cosmic history – from within our solar system to the most distant observable galaxies in the early universe, and everything in between. Webb will reveal new and unexpected discoveries, and help humanity understand the origins of the universe and our place in it.

The launch readiness date for the James Webb Space Telescope is moving to no earlier than Dec. 22 to allow for additional testing of the observatory, following a recent incident that occurred during Webb’s launch preparations.

The incident occurred during operations at the satellite preparation facility in Kourou, French Guiana, performed under Arianespace overall responsibility. Technicians were preparing to attach Webb to the launch vehicle adapter, which is used to integrate the observatory with the upper stage of the Ariane 5 rocket. A sudden, unplanned release of a clamp band – which secures Webb to the launch vehicle adapter – caused a vibration throughout the observatory.

A NASA-led anomaly review board was immediately convened to investigate and instituted additional testing to determine with certainty the incident did not damage any components. NASA and its mission partners will provide an update when the testing is completed at the end of this week.

Webb was previously scheduled to launch Dec. 18 on an Arianespace Ariane 5 rocket from Kourou.

The Webb Space Telescope is an international partnership with the European and Canadian space agencies. It will explore every phase of cosmic history – from within our solar system to the most distant observable galaxies in the early universe, and everything in between. Webb will reveal new and unexpected discoveries, and help humanity understand the origins of the universe and our place in it.

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!

“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