The next step in our journey to know the cosmos will take place in Kourou, French Guiana exactly one year today.

On October 31, 2021—a Sunday—NASA, the European Space Agency (ESA) and the Canadian Space Agency (CSA) will launch the James Webb Space Telescope (JWST or “Webb”).

There are rocket launches every week. Why should anyone get excited about yet another one?

This one’s going to be different—it will be both expensive and expansive.

Rated as 100 times more powerful than the Hubble Space Telescope, Webb will depart from the European Spaceport’s ELA-3 launch complex atop an Arianespace Ariane 5 rocket.

It will be stuffed with an origami-like structure that will fold-out once in space, but it will also be full of the hopes and dreams of space fans, stargazers, amateur astronomers and scientists.

What is Webb?

It’s a $8.8 billion space telescope—NASA’s next great space science observatory—and the successor, in many ways, to Hubble. It’s about the size of a tennis court. It’s the world’s largest, most powerful and complex space science telescope ever constructed. It’s named after James E. Webb, NASA’s administrator during some of the Apollo era.

The golden mirror of the James Webb Space Telescope contains 18 segments, designed to captured light from the earliest ages of the Cosmos. Image credit: NASA/Desiree Stover

The James Webb Space Telescope will be the world’s premier space science observatory when it launches in 2021. Webb will solve mysteries of our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it.

Once in position its five-layered sized sunshield will unfold to reveal a 6.5-meter primary mirror that will be able to detect the faint light of stars and galaxies. During its 10-year mission Webb will:

• study the Solar System.
• take photos of exoplanets.
• reveal galaxies never before seen by humanity—the first galaxies.
• explore the mysteries of the origins of the Universe.

Webb will be able to see what the universe looked like around a quarter of a billion years (possibly back to 100 million years) after the Big Bang, when the first stars and galaxies started to form.

Where is Webb going?

After departing the European Spaceport to the northwest of Kourou in French Guiana, South America, Webb will travel 1 million miles/1.5 million kilometers over the following 30 days to the second Lagrange point, also called L2.

At this very special place in space the Webb will be able to stay in line with the Earth as it moves around the Sun.

Unlike the Hubble Space Telescope, which orbits Earth so it can only observe when it’s on the planet’s night-side, Webb will have a sunshield to deflect the Sun’s light and heat and be able to observe constantly.

Being at L2 also gives Earth a direct line-of-sight to Webb at all times so NASA can send instructions and receive data at any time via its Deep Space Network antennas.

What will Web tell us about exoplanets? Will it take photos of exoplanets?

Webb will be able to tell us the composition of the atmospheres of exoplanets. It will observe planetary atmospheres through the transit technique. A transit is when a planet moves across the disc of its parent star.  Webb will also carry coronographs to enable photography of exoplanets near bright stars (if they are big and bright and far from the star), but they will be only “dots,” not grand panoramas.  Consider how far away exoplanets are from us, and how small they are by comparison to this distance! We didn’t even know what Pluto really looked like until we were able to send an observatory to fly right near it, and Pluto is in our own solar system!

On Further Reflection…

The Webb Telescope will, almost certainly, rise from Earth one day in the coming years. Assuming a successful launch, the observatory will head more than 1.6 million kilometers (one million miles) from Earth, to the L2 Lagrange point, above the nighttime side of our planet. There, it will join the Planck Space Observatory and the Herschel Space Telescope.

Sporting a mirror eight meters (25 feet) in diameter, the Webb Telescope will be capable of collecting images and data from the first stars and galaxies which came into being. This instrument will unravel some of the deepest mysteries of all about the earliest eras of the Cosmos, utilizing the largest mirror ever sent into space.

Once Webb opens its magnificent golden eye to space, the observatory will study the oldest, most distant objects in the Cosmos in infrared light, and assist in the search for exoplanets which could be home to extraterrestrial life.