On December 25, 2021, NASA launched the James E. Webb Space Telescope (JWST) (see Exhibit 1), the successor to the Hubble Space Telescope. The telescope was launched from the Ensemble de Lancement Ariane 3 (ELA-3) launch complex near Kourou, French Guiana, on an Ariane 5 rocket from the European Space Agency. With its successful deployment, the telescope will help us understand the universe’s past by giving us the ability to see the earliest stars formed.

Background

In 2002, JWST was given its name after James E. Webb, the administrator for NASA from 1961-1968, who played an important role in the Apollo program, the history of the telescope began about a decade prior. The idea for the telescope came to fruition in 1989 as a possible successor to Hubble even before it had launched in 1990. Issues with imaging on the Hubble immediately after launch put the next generation space telescope (NGST), which was the Webb’s informal name, on the backburner, which led to NASA losing about three years of planning time during repairs; however, by the mid 1990s, NASA decided that the main purpose for the telescope was to study the early universe. NASA scientists decided early on that the telescope would use infrared instead of ultraviolet (UV) and visible light that Hubble uses. They also decided that the telescope would have to be big to collect the most amount of photons (electromagnetic particles) for study. The design was practically done in 1996 with an estimated cost of $1 billion and could launch at the earliest in 2007. Despite NASA’s wishful thinking, the project ended up costing $10 billion and taking almost an additional 15 years past the proposed launch date. The project was almost cut in 2011, but scientists and some influential politicians, without whom the telescope would have never been completed, saved it. Another factor leading to the success of the telescope was the contribution of the European Space Agency (ESA) and Canadian Space Agency (CSA) that joined the project in 1997.

Webb v Hubble

Webb is considered the replacement for Hubble (see Exhibit 2), leaving many to compare the two. The main difference is in the wavelengths of light on the electromagnetic spectrum (EMS) through which they make their viewings. The Hubble uses mainly visible light and some UV and infrared, whereas Webb will use solely infrared. In fact, Webb uses two types of infrared, near infrared and mid infrared; near infrared being closer to the wavelength of radiation detectable by the human eye, and mid infrared being further away. Using both allows the telescope to gather more information about celestial objects. Infrared can help see through the gas and dust clouds that are throughout space and inhibit telescopes like Hubble from seeing past them. 

Features

Webb has six times the light collecting power of Hubble with its 18 beryllium and gold coated hexagonal pieces that make up its main mirror. A secondary mirror will absorb light from these primary mirrors and reflect it onto four instruments in the telescope that will analyze the light gathered. 

One of the most important features of the observatory is the tennis court-sized sunshield that, like its name, serves to shield the telescope and all of its parts from the sun, as the telescope needs to be extremely cold (about negative 370 degrees Fahrenheit) for the optics to operate properly and detect even the faintest heat signals. The shield is made up of five thin layers made of Kapton, a material that is very heat-resistant, and coated in aluminum. The two layers closest to the sun have a silicon coating to reflect the sun’s heat. Webb Sunshield Manager, James Cooper, explained the odd kite shape of the shield, “The shape and design also direct heat out the side… heat generated by the spacecraft bus at the ‘core,’ or center, is forced out between the membrane layers so that it cannot heat up the optics.”

Launch

As with every launch, testing, testing, testing, and even more testing preceded it until the launch finally occurred successfully on Christmas day in French Guiana; this location was chosen specifically because when it comes to launching space-bound vessels, the closer to the equator the better, as the spin of the earth can give an additional push. Before the launch, the telescope had to be completely folded to fit into the Ariane 5 rocket. As the rocket successfully launched, it separated from the rocket a half an hour later, beginning a voyage built on 30 years of hard work and perseverance.

Deployment Plan/Future

Unlike Hubble that is within Earth’s orbit, Webb will be orbiting a very specific area behind the Earth, in the Earth’s magnetotail called the Lagrange 2 (L2) point, which is about 930,000 miles away from Earth, a distance NASA hopes it will cover over the course of 29 days. During this time, Webb will be deploying the parts that had to be folded up to fit in the Ariane 5 rocket. Webb will begin by deploying its solar array, followed by the communications antenna, and a longer period where the sunshield will be completely unfolded. After that, the secondary and then primary mirrors will be deployed very slowly to ensure they line up properly. Throughout the trip, the Webb team will make trajectory maneuvers to keep the telescope on course to the L2 point. Once the telescope makes it to the L2 point, there are no plans to service Webb as that area is too hard to reach from Earth.

The mission is intended to last five years with enough fuel for ten. Already the time that the telescope will be used for certain objectives has been divided up amongst planetary scientists. Webb has the ability to track celestial objects in our solar system past Mars, which is how the first 100 hours are planned to be spent after it finishes completely deploying. Planetary scientists will use this to find data and measurements of celestial bodies in our solar system to share with the scientific community. 

The achievement of deploying the Webb in space was built upon the work of its predecessor telescope, Hubble, and the work of countless people over the course of decades. With the biggest astronomical achievement in 30 years already on its way to its orbital point, we’ll have to wait and see what NASA will build next to supersede it.