James Webb Space Telescope

It is said that the Hubble Space Telescope is the most important advance in astronomy and astrophysics since Galileo put lenses at the ends of a tube, and looked skyward.

Later this month, an Ariane 5 rocket will take off from the Spaceport in French Guiana, carrying what is likely to be the most important advance since Hubble – the James Webb Space Telescope (JWST).

JWST is not intended to replace Hubble, but to work in concert with it. Hubble works mostly in the visible light range, which collects amazing images, but is limited in the distance it can see. The JWST is designed to work with infrared light, extending the range of detection.

In our rapidly expanding universe, distant objects are retreating from us so rapidly that the light waves they emit are stretched (so-called 'red-shifted') beyond the wavelength of visible light. This is akin to the way the sound of a train is high pitched as it approaches, then drops to a lower pitch as it moves away.

Because JWST works primarily in the longer wavelength infrared range, it will allow us to see back to very near the beginning of our universe (within a hundred million years or so). JWST also has some benefit for viewing nearer objects, since infrared light is not blocked by the massive interstellar dust clouds that obscure many of the formations viewed, but obscured by Hubble.

The next few months will be very stressful for those involved in, or who care about, this project. There are many things that can go wrong, even after launch. JWST will have to reach, and settle at a stable 'Lagrange point' over a million miles from Earth. If a problem is found—as happened with Hubble—we will not have the option of sending a team to repair it. This link has some details about it's planned position, as well as some other trivia.

https://webb.nasa.gov/content/about/orbit.html