NASA announced yesterday that it has completed the construction of the world's largest space telescope, the James Webb Space Telescope (JWST), after almost two decades of construction. The next-generation $8.8 billion heir to the 26-year-old Hubble Space Telescope will be launched on board an Ariane 5 rocket from French Guiana to a place called the second sun-Earth Lagrange point, located four times the distance between the Earth and the moon in October 2018.
The JWST is equipped with mirrors 2.7 times bigger than Hubble’s and powerful detectors that can observe very infrared lights 400 times fainter than current space-based telescopes can see, as Space.com points out, even through cosmic dust and atmospheres of exoplanets.
"Today, we're celebrating the fact that our telescope is finished, and we're about to prove that it works," John Mather, an astrophysicist and senior project scientist for the telescope said in a news conference as reported by Space.com. "We've done two decades of innovation and hard work, and this is the result – we're opening up a whole new territory of astronomy."
While Hubble is credited with unveiling important discoveries including the acceleration of the universe’s expansion, the JWST is expected to go even further by exploring the birthplaces of planets, stars, and first galaxies born after the Big Bang more than 13.5 billion years ago with its sensitive infrared cameras.
These observations will not only help scientists understand the origins of the universe but at the same time, look for signs of life in other planets.
"We'd like to know if another planet out there has enough water to have an ocean, and we think we can do that," Dr. Mather said about one of the project’s missions to explore the Alpha Centauri system.
"We will see things we have not seen before because this telescope is much more powerful than even the great Hubble telescope," Mather said, adding "To give you some perspective about what we can do with it. If you were a bumblebee at a distance of the moon, we will be able to see you, both by your reflective sunlight and by thermal radiation and heat you emitted."
NASA's engineers and technicians working on the telescope successfully completed the first important optical measurement of Webb's fully assembled primary mirror, known as a Center of Curvature test, to measure the mirror's shape by comparing light reflected off of it with light from a computer-generated hologram that represents what Webb’s mirror ideally should be.
Next, the 6.5-meter primary mirror consisting of 18 hexagonal mirrors will go through a series of rigorous tests that will simulate the violent sound and vibration environments the telescope will experience inside its rocket on its way out into space.
The Center of Curvature test will be repeated after the launch environment testing and the results compared to find if there are any changes or damages to the optical system.
The Daily Galaxy via NASA