Science

After 20 years, James Webb Space Telescope finally heads to space

The next generation telescope is on its way out of here.

NASA’s James Webb Space Telescope (JWST) successfully launched on Saturday at 7:20 a.m. Eastern, initiating a new era of astronomical observations that will illuminate never-before-seen parts of the cosmos.

After years of anticipation, and plenty of delays, the telescope launched aboard an Ariane 5 rocket from the European Spaceport launch complex near Kourou, French Guiana. The mission has a long 30 days ahead, during which it will need to slowly unfurl as it is carried to a perch around 1 million miles away from Earth at a gravitationally stable point called Lagrangian point 2 (L2), where the Sun and Earth’s gravity are canceled out.

Webb has suffered several delays that have postponed the mission for years. NASA’s most ambitious mission took nearly two decades to develop, and NASA initially slated it for a 2018 launch date, which was then pushed back to 2020 and later to several dates in 2021.

The mission’s overall cost is about $10 billion.

Webb’s Ariane 5 at liftoff. NASA/ESA

What is the James Webb Space Telescope’s mission?

JWST is the biggest and most complex telescope ever built by NASA.

The telescope sports a 21-foot-wide, 4-inch-thick tiling of 18 beryllium mirrors coated in gold, acting as one large mirror. This will enable it to observe distant objects in the universe better than any other instrument in the world, due to its size and location far away from Earth.

Infrared capabilities will help the telescope see beyond what we can in visible ranges — including staring right through otherwise opaque areas of space. These wavelengths aren’t possible from Earth, giving JWST unique capabilities unmatched by any telescope to date.

Using its large mirror, the telescope will probe the atmospheres of potentially habitable exoplanets, peer back in time at galaxies that formed during the early years of the universe, and investigate Solar System moons that may have some form of life in their subsurface oceans.

Webb after its faring separated, with the telescope preparing to unfold. NASA/ESA

What happens after JWST launches?

The telescope has a bit of a long ride into deep space following its launch.

At L2, Webb will need a solar shield — about the size of a tennis court — to protect itself from the Sun. The L2 orbit ensures that it can stay facing away from the Sun at all points, protecting itself against the light and heat of the star.

JWST’s orbit also keeps the telescope out of the shadows of both the Earth and Moon, allowing it to have an unobstructed view of the universe for the entire duration of its orbit. Meanwhile, Hubble goes in and out of Earth’s shadow every 90 minutes.

Once it is in orbit, the mission team on the ground will double-check its instruments to make sure it’s working properly, which will take a few months. JWST will fully begin operations around mid-summer of the year 2022.

Share: