NASA’s James Webb Space Telescope has begun its stately rollout to the Arianespace ELA-3 launch complex at Europe’s Spaceport located near Kourou, French Guiana. Arianespace and NASA will closely monitor the vitals of Webb and the Ariane 5 rocket during the nearly two-hour process. Webb is scheduled for liftoff at 7:20 am EST Saturday, Dec. 25.
NASA, ESA (European Space Agency), and Arianespace confirmed a targeted launch date of Saturday, Dec. 25, for the James Webb Space Telescope. A 32-minute launch window opens at 7:20 a.m. EST in Kourou, French Guiana (9:20 a.m. GFT/12:20 UTC).
An Ariane 5 rocket will lift off from Europe’s Spaceport carrying NASA’s next-generation space observatory.
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Update: 4:30 p.m. EST, Dec. 21, 2021:
NASA and Arianespace successfully completed the Launch Readiness Review for the James Webb Space Telescope on Dec. 21. The team authorized the Ariane 5 rocket carrying Webb to rollout and the start of launch sequencing for the mission.
However, due to adverse weather conditions at Europe’s Spaceport in French Guiana, the flight VA256 to launch Webb – initially scheduled for Dec. 24 – is being postponed.
The new targeted launch date is Dec. 25, as early as possible within the following launch window:
Tomorrow evening, another weather forecast will be issued in order to confirm the date of December 25. The Ariane 5 launch vehicle and Webb are in stable and safe conditions in the Final Assembly Building.
NASA’s James Webb Space Telescope has cleared its launch readiness review, and has been given the formal green light to proceed with final preparations for liftoff planned for Dec. 24.
Additionally, Webb teams recently completed a comprehensive day of launch rehearsal that involved a joint effort between launch site crews in French Guiana, and Webb’s Mission Operations Center (MOC) at the Space Telescope and Science Institute in Baltimore, Maryland. The various teams involved with launching Webb are all standing at the ready, and have practiced each step routinely.
Next, the Ariane 5 rocket — with Webb safely encapsulated on top — is planned to begin the nearly two hour process of rolling out to the launch pad on Dec. 22.
The James Webb Space Telescope is confirmed for the target launch date of Dec. 24, at 7:20 a.m. EST.
Late yesterday, teams at the launch site successfully completed encapsulation of the observatory inside the Ariane 5 rocket that will launch it to space. Webb’s final launch readiness review will be held on Tuesday Dec. 21 and, if successful, roll-out is planned for Wednesday, Dec. 22.
Details of NASA’s prelaunch, launch, and postlaunch coverage are available on the agency’s website.
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.
