The James Webb Space Telescope

The replacement to the Hubble space telescope is planned to launch on December 18th. With production beginning all the way back in 2004, it cost a staggering $9.66 billion dollars to manufacture, including operational costs. It is an infrared telescope, which will allow us to see galaxies 100 million years after the Big Bang or 13.6 billion years ago, compared with Hubble’s 13.5 billion. It will be orbiting the Sun at the Lagrange point 2, a million miles away from Earth. Its main task is examining the atmospheres of exoplanets. It will be able to send back the first images around 6 months after launch with a resolution 100 times better than the Hubble. Let’s look at some interesting details and explain how it works.

The fully constructed James Webb telescope, which is the largest and most complex humanity has ever built. Notice the honeycomb structure of the antenna panels. Credit: NASA.

The James Webb telescope operates like a reflector, with a larger mirror that captures infrared light and sends it to a smaller mirror which then reflects it onto a sensitive detector. If you want to find out more, check out the post on telescopes. The telescope uses infrared light, which can be manifested as heat. Therefore, on one side it is heavily shielded from the Sun, in order to limit interference. On the Sun facing side, there is also the computer and devices used to communicate with Earth. On the other side, the instruments and mirrors are kept cold at -233°C, to ensure optimal working conditions.

What is the Lagrange point 2? In the 18th century Lagrange found five solutions to the three body problem, which are stable orbits where the objects stay in the same position relative to each other. This will allow it to keep in constant communication with the Earth. This position is held by the gravitational fields of the Earth and the Sun, which means little rocket power will be needed for adjustments. However, it will not just sit stationary in L2, it will orbit around the point with a period of 6 months. This keeps it out of Earth’s and Moon’s shadow, which will allow continuous operation as the Hubble gets in shadow every 90 minutes. This will allow for longer exposure times. Take a look at this video if you want to see a simulation of the orbit. It is not the first object to be put in L2, as the WMAP and Planck satellites have been there before. It will take around 30 days to reach that point.

The five Earth-Sun Lagrange points. Credit: NASA.

There has been a great deal controversy around its name. James Webb was a NASA administrator that oversaw the Apollo program. Nevertheless, this was also the era of the Lavender Scare, when LGBTQ employees were hunted down and forced to quit. While, Webb’s name does not appear in many documents, David K. Johnson who wrote a 2004 book on the Lavender Scare claims that he helped establish the “modus operandi” of the Hoey Committee when he was acting as undersecretary. In March 2021, four astronomers wrote an article in the Scientific American and created a petition which gathered 1700 signatures from other experts in the field. This pushed NASA to launch an investigation into the name in July, nonetheless the result of it was keeping the name. Another proposed name was the Harriet Tubman telescope. Tubman was an abolitionist who escaped slavery and then made 13 brave return missions to rescue 70 more enslaved people. According to Chanda Prescod-Weinstein, she “represents the best of humanity, and we should be sending the best of what we have to offer into the sky”. I think it is a fantastic idea, if we are not naming it after a scientist in the first place. Names can be changed, so hopefully NASA will go back on its decision in a few years with more pressure from the scientific community.


Andrew, S. C. (2021, November 19). NASA’s James Webb Space Telescope is about to launch. Some want to rename it. CNN.

Davis, J. C. (2021, November 19). NASA’s new telescope and the search for clues about our universe explained. CNN.

Howell, E. (2021, November 18). NASA’s huge James Webb Space Telescope is one month from launch. Space.Com.

Orbit – Webb/NASA. (n.d.). NASA.

Perception. (2021, July 17). The James Webb Space Telescope Explained In 9 Minutes. YouTube.

Published by Mateusz Ratman

High school student from Warsaw, Poland. JHU Class of 2026.

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