Webb Telescope new launch date December 18

Webb Telescope: A huge boxy structure poised on scaffolding in a giant white clean room.
Fully assembled and fully tested, the Webb Telescope completed its primary testing and is preparing for shipment to its launch site at Europe’s Spaceport in French Guiana. In this photo, the Webb is folded as it will be for launch. Image via ESA.

Webb Telescope is Hubble’s successor

NASA said on September 8 that it now has a new official launch date for the James Webb Space Telescope: December 18, 2021. The agency set the new target launch date after the Webb successfully completed a rigorous testing regimen. NASA called the testing:

… a major turning point for the mission.

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The European Space Agency (ESA) had reported on the tests’ completion, too, on August 26, 2021. ESA said at that time that the Webb was being prepared for shipment to its launch site from the European Spaceport located near Kourou, French Guiana. Webb is an international partnership between NASA, ESA and the Canadian Space Agency.

Earlier in the summer, on June 3, NASA announced that the telescope would ship to the launch site in August “with little to no schedule margin.” That tight schedule would bring the telescope to launch readiness no earlier than October 31. Now the new launch date of December 18, 2021, has been announced.

The space telescope underwent testing at Northrop Grumman’s facilities in California. ESA said:

Shipment operations have now begun. All the necessary steps are being taken to prepare Webb for a safe journey through the Panama Canal to its launch location … on the northeastern coast of South America.

Once Webb arrives at Europe’s Spaceport, launch processing teams will prepare and configure the observatory for flight. This involves post-shipment checkouts and carefully loading the spacecraft’s propellant tanks with fuel. Then, engineering teams will mate the observatory to its launch vehicle, an Ariane 5 rocket provided by ESA, and make a ‘dress rehearsal,’ before it rolls out to the launch pad two days before launch.

A graphic with several diagrams of the launch vehicle and deployment of the Webb in space.
View larger. | Webb will fly to orbit on an Ariane 5 rocket. The European Space Agency is providing the launch service. This timeline illustrates the Webb launch campaign of almost 70 days. It involves a team of more than 100 experts hosted at Europe’s Spaceport. NASA is highly involved, working closely with ESA toward launch. Read more via ESA.

Launch from near Earth’s equator

Video of simulation of the Webb’s launch and deployment, from the Space Telescope Science Institute.

The upper stage of the Ariane 5 which will carry Webb to space later this year is already on its way to Europe’s Spaceport. Overnight on August 17, 2021, the upper stage was transported in its container from ArianeGroup in Bremen to Neustadt port in Germany. Here it boarded the MN Toucan vessel, alongside other Ariane 5 elements loaded in various European harbors, to continue its journey to Kourou, French Guiana.

Following launch, the massive space observatory will then make its way to Lagrange Point 2, a gravitationally stable point 930,000 miles (1.5 million km) from our planet. Webb will take about a month to fly to this location in space. As it travels there, beginning a few days after launch, it’ll begin slowly unfolding its biggest feature, its tennis court-sized sunshield, designed to reduce the sun’s heat by more than a million times to -364 degrees F (-220 degrees C). Webb’s mirror and instrumentation have to be kept cold. If they were to be heated up by the sun, they’d give off infrared radiation. And it’s faint infrared signals from the distant cosmos that the Webb is meant to measure. ESA commented that each step of the cool-down process:

… can be controlled expertly from the ground, giving Webb’s launch full control to circumnavigate any unforeseen issues with deployment.

ESA said the mission team can manage the cool-down, which will take several weeks, with heaters to control stresses on instruments and structures. In the meantime, ESA said:

… the secondary mirror tripod will unfold, the primary mirror will unfold, Webb’s instruments will slowly power up, and thruster firings will insert the observatory into a prescribed orbit.

After orbital insertion, and after the telescope has cooled down and stabilized at its frigid operating temperature, the mission team will spend several months aligning its optics and calibrating its scientific instruments. Then Webb will begin studying the cosmos in infrared light using its dazzling golden mirror.

Diagram of Earth and moon, with Hubble and Webb's orbital distances compared.
The Webb will orbit the sun about a million miles (1.5 million km) away from the Earth, at what is called the 2nd Lagrange point or L2. Note that this graphic is not to scale. Image via NASA.

What’s huge, grand, and golden?

One of the Webb’s most important and identifiable attributes is its 21-foot-wide (6.5-meter-wide) primary mirror. A reflecting telescope’s primary mirror determines how much light it can collect, and thus how deeply it can see into the universe. Webb’s mirror is nearly three times wider than Hubble’s primary mirror.

You might hear people speak of the Webb’s golden mirror. The mirror is actually multiple mirrors. It’s composed of 18 separate hexagonal-shaped segments made of very strong, ultra-lightweight beryllium, which will unfold after launch. Each of the telescope’s mirror segments is covered in a microscopically thin layer of gold. This gold covering optimizes the mirror segments for reflecting infrared light, which is the primary wavelength of light this telescope will observe.

Webb Telescope has had a long road

The Webb’s development began in 1996, with a $500 million budget. Space scientists and engineers initially planned the launch for 2007. But the project has had considerable delays and cost overruns, and it underwent a major redesign in 2005. Afterward, they planned the launch for March 2020, but the coronavirus pandemic struck and caused major setbacks.

Yet, now, the team has made significant progress. NASA says existing program funding will have the Webb finished within its current $8.8 billion cost cap. In December 2020, the sunshield of a fully assembled James Webb Space Telescope successfully completed its own final tests, including a complete unfolding, just as the telescope will need to do once in space.

Formerly known as the Next Generation Space Telescope, scientists renamed the Webb in September 2002 after James Webb, who was an esteemed former NASA administrator.

NASA, the European Space Agency, and the Canadian Space Agency are partnering on the Webb. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the development effort, while Northrop Grumman serves as the project’s main industrial partner. 

As it has for the Hubble Space Telescope, the Space Telescope Science Institute in Baltimore will be operating the Webb telescope after launch.

Small human figure on left, gray filled circle with white hole in center, much larger hexagon made of 18 gold hexagons to right.
Webb will have a 21-foot-diameter (6.5-meter-diameter) primary mirror. Hubble’s mirror is about 8 feet (2.4 meters) in diameter. Note the human figure for scale. Image via NASA.

Technologies advance

As you would expect, the capabilities of the Webb extend beyond those of the Hubble Space Telescope. NASA likes to say that the Webb is not a replacement for Hubble, but rather a successor. The two telescopes will collaborate side by side for a while, with a planned overlap.

The Webb will observe farther into the infrared regions of the electromagnetic spectrum than Hubble. It’ll go even deeper into space than Hubble, and thus it’ll look farther into the past. It’ll be able to peer inside stellar dust clouds where stars and star systems form. Thaddeus Cesari, a communications specialist for the mission, wrote:

In addition to the groundbreaking science expected from it after launch, Webb has required an improvement in the testing infrastructure and processes involved in validating large complex spacecraft for a life in space … Lessons learned from previous space telescope development were invested into Webb, and future space telescopes will be built upon the same collective knowledge.

Thousands of scientists, engineers, and technicians contributed to build, test, and integrate Webb. In total, 258 companies, agencies, and universities participated: 142 from the United States, 104 from 12 European nations, and 12 from Canada.

A golden, hexagonal mirror made of smaller hexagons, floating in space.
Artist’s concept of the James Webb Space Telescope deployed in space, via ESA.
A 2-panel image with dense clouds in space on the left and the same clouds more tenuous with more stars on right.
How we see objects in space depends upon which wavelengths of the electromagnetic spectrum are being received by the telescope. Here’s a comparison of the Carina Nebula, a gas and dust cloud, viewed in visible light (left) and infrared (right). The infrared image shows stars that were hidden behind dust in optical light. Image via NASA/ ESA/ Hubble 20th Anniversary Team.
Larger Webb telescope with open gold reflector dish to the left and Hubble with tube to the right.
Artist’s concept of the overall size comparison of the Webb (left) and Hubble (right) telescopes. Image via GSFC/ NASA.

Bottom line: The James Webb Space Telescope is the world’s most complex infrared telescope. On September 8, NASA announced a new official launch date for the telescope: December 18, 2021.


September 8, 2021

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