After more than two decades of development, NASA’s next-generation space telescope is on the launch pad. The James Webb Space Telescope is due to launch on Saturday, December 25 during a 32-minute window that opens at 7:20 a.m. EST (1220 GMT).
On Thursday, December 23, the space telescope, safely stowed inside the fairing of ESA’s Ariane 5 launch vehicle, left the final assembly building for the nearly two-hour roll-out to the launch pad at Europe’s Spaceport in French Guiana, reports The ESA in an update.
Since its encapsulation inside the fairing of the Ariane 5 launch vehicle on December 17, the space telescope has been carefully monitored. Inside the fairing are specialized environmental controls that keep the telescope in a perfectly controlled temperature and humidity range during its final few days on Earth.
Ariane 5, standing 53 meters (173.8 feet) high on its mobile launch platform was transported along rails from the final preparation building to the launch zone where final health checks and preparations for liftoff will occur.
This includes filling the propellant tanks of the Ariane 5 core stage with liquid oxygen and liquid hydrogen via lines through the launch table.
Final electrical and software configurations will also occur on the launch pad. Webb will switch to internal battery power about 20 minutes prior to liftoff on Saturday morning, and within 15 minutes prior to liftoff the observatory and its launch vehicle will both be fully cleared for flight.
Webb is an international partnership between NASA, ESA (European Space Agency), and the Canadian Space Agency. Once it is launched, the James Webb observatory will spend its first month in space unfurling in a complicated deployment sequence and trekking out to its station some 1 million miles (1.6 million kilometers) away from Earth.
By mid-2022, scientists hope, the telescope will begin gathering observations of the solar system, the galaxy, and far, far beyond. The observatory will specialize in gathering infrared light, which will help astronomers study the very beginnings of the universe.
Whereas the Hubble Space Telescope sees our universe from low-Earth orbit, Webb will travel out much farther, to a gravitationally stable spot 930,000 miles (1.5 million kilometers) from Earth known as the Sun-Earth Lagrange point 2 (L2).
Lagrange Points are positions in space where the gravitational forces of a two-body system like the Sun and the Earth produce enhanced regions of attraction and repulsion.
There are five Lagrange points where a small mass can orbit in a constant pattern with two larger masses. And because the Webb telescope will be much further out from Earth than the Hubble, with its giant gold mirror and infrared light observation tools, Webb will “see” objects 10 to 100 times fainter than what Hubble can see.
The Hubble telescope observes light at primarily optical and ultraviolet wavelengths, while Webb is designed to detect primarily infrared light.
“It will take amazing images; they will be better than what Hubble did,” Klaus Pontoppidan, Webb project scientist at the Space Telescope Science Institute in Baltimore, said during a news conference in May. But, while better in ways, Webb’s images will also be fundamentally “different, because it’s different wavelengths,” Pontoppidan said.
