James Webb Space Telescope, the largest space observatory in history, will be launched from Europe’s Spaceport, the Guiana Space Center in Kourou, French Guiana on December 25, 2021 5.50 pm (India Time).
Called as the successor to the famous Hubble telescope, the James Webb Space Telescope aboard an Ariane 5 Rocket has made the two-hour trek out to the launch pad on Wedneday.
The Webb Space Telescope is an international partnership of NASA with the European and Canadian space agencies. Webb is expected to reveal new and unexpected discoveries,and help humanity understand the origins of the universe and our place in it. It will explore every phase of cosmic history–from within our solar system to the most distant observable galaxies in the early universe, and everything in between.
James Webb Space Telescope is 100 times more powerful than Hubble. It has a 5-layer sunshield that protects the telescope from the infrared radiation of the Sun, Earth, and Moon and can fit in the rocket and will unfold like a “Transformer” in space.
While Hubble orbits 560 kilometers above the Earth, James Webb Space Telescope will orbit the Sun 1.5 million kilometers from the Earth.
Hubble Telescope vs. James Webb space telescope
“Comparing Hubble and Webb is like asking if you will love your second child as much as your first,” Susan Mullally, Webb’s deputy project scientist at the Space Telescope Science Institute in Baltimore told AP.
“Hubble will always be loved for its awe-inspiring images of our universe and will continue to collect important data for astronomers. Webb gives us new and unique eyes of places that we have never been able to reach.”
Hubble caught a lift to orbit tucked inside NASA’s space shuttle Discovery in 1990. It quickly ran into trouble: one of the telescope’s solar wings jammed as it was unfurling. Astronauts suited up for an emergency spacewalk, but commands from Earth freed the panel. Within weeks, Hubble’s blurry vision was detected. Spacewalking astronauts fixed it three years later. Soaring from South America on a European Ariane rocket, Webb won’t be reachable by astronauts at its destination 1 million miles (1.6 million kilometers) away. Bigger and more intricate than Hubble, Webb will be a goner if its foldout mirror and sunshield snarl.
LET THERE BE LIGHT
Webb is expected to behold light from the universe’s first stars and galaxies, beyond Hubble’s range. This light will reveal how the original stars looked 13.7 billion years ago. Hubble has stared as far back as 13.4 billion years, disclosing a clumpy runt of a galaxy that is currently the oldest and farthest object ever observed. Astronomers are eager to close the 300 million year gap with Webb and draw ever closer in time to the Big Bang, the moment the universe formed 13.8 billion years ago. “It’s like looking at the picture book of my kids and missing the first two years, right? Trying to figure out where they come from,” said NASA science chief Thomas Zurbuchen.
Hubble sees what we see—visible light—with a little ultraviolet and infrared thrown in. Webb has infrared vision, allowing it to pierce cosmic clouds of dust. The shorter visible and ultraviolet wavelengths emitted by the first stars and galaxies have been stretched as the universe expands, so Webb will see them in their elongated, heat-emitting infrared form. That’s why Webb’s detectors need to run at minus 400 degrees Fahrenheit (minus 240 degrees Celsius). To stay chilled, Webb carries a parasol the size of a tennis court. Between each of the sunshield’s five layers is a gap so heat can escape out the sides. Multiple layers also better protect against micrometeorite hits.
To discern the universe’s first, faint stars, Webb requires the largest mirror ever launched for astronomy. The mirror spans more than 21 feet (6.5 meters), yet is lighter than Hubble’s, which is 8 feet (2.4 meters) across. That’s because Webb’s mirror is made of beryllium, a strong but lightweight metal. It’s also segmented, allowing it to fold like a drop-leaf table for launch. Each of the 18 hexagonal segments are the size of a coffee table and coated with ultra-thin gold, an ideal reflector of infrared light.
LOCATION, LOCATION, LOCATION
Hubble circles 330 miles (530 kilometers) overhead. The altitude was dictated by the capabilities of NASA’s space shuttles, which delivered Hubble to orbit and then made five service calls. Webb is bound for more a more distant spot — 1 million miles (1.6 million kilometers) away at what’s called the second Lagrange point. This is where the gravitational forces of the Earth and sun balance, requiring minimal fuel for a spacecraft to stay put. Webb will constantly face the nightside of Earth as the spacecraft and planet swoop around the sun in unison.
Hubble was years late and millions over budget by the time it rocketed into orbit in 1990. Webb also is years late with huge cost overruns. NASA’s tab for Hubble from its 1970s development until now: $16 billion, adjusted for inflation. That doesn’t include all the shuttle flights for launch and repairs. Webb’s price tag is an estimated $10 billion; that includes the first five years of operation. The European Space Agency is picking up the launch costs, with a French-built Ariane rocket providing Webb’s lift from French Guiana.
(With inputs from NASA, AP)