What is the James Webb Space Telescope?

Webb stands at more than three stories tall and is as broad as a tennis court. As the world’s most complex and powerful space science observatory. It will transform our view of the universe. 

The mirror is over six times bigger in area than the Hubble Space Telescope’s.


The mirror segments are covered with a golf ball’s mass of gold, which optimizes them for reflecting infrared light. The coating is so thin that a human hair is 1,000 times thicker!

The observatory will travel to an orbit about one million miles away from Earth and undergo six months of commissioning in space — unfolding its mirrors, sunshield, and other smaller systems; cooling down; aligning; and calibrating.

Webb’s infrared capabilities will allow it to gaze into the age when the very first stars and galaxies formed, over 13.5 billion years ago. 

It will shed light on how galaxies evolve, how stars and planetary systems are born, and how the building blocks of life could form on other planets, showing us things never before seen by any other telescope.

Webb will observe and conduct studies of planets located in the habitable zones of nearby stars, the regions where a planet could harbor liquid water on its surface.

Scientists will use the space telescope to study planets and other bodies in our solar system to determine their origin and evolution and compare them with exoplanets, planets that orbit other stars.

Take Mars for example. Webb will be able to study the Red Planet’s local features. It will observe whether the atmosphere of Mars reveals any history of habitability, as well as how the atmosphere has changed over time. 

A joint mission between NASA, the European Space Agency, and the Canadian Space Agency, it’s the largest international space science project in U.S. history. Thousands of scientists, engineers, and technicians from 14 countries and 29 U.S. states designed and built Webb.