James Webb Space Telescope launch into space set for Christmas; 5 things to know

The largest space telescope ever, the James Webb Space Telescope launch will happen on the Ariane 5 rocket.

After James Webb Space Telescope is launched, NASA will place it in the Sun’s orbit. (ESA Instagram)

The largest space telescope ever, the James Webb Space Telescope launch is going to happen on Christmas day, December 25, 2021, after decades of waiting. It has already been assembled on the top of the Ariane 5 rocket which will launch to space from Europe's Spaceport in French Guiana. The engineering marvel is expected to provide answers to fundamental questions about the Universe. Here are five things that you should know about the James Webb Telescope ahead of its launch:

1. It has a giant gold mirror

The telescope's centrepiece is its enormous primary mirror, which is a concave structure of 21.5 feet (6.5 meters) width and made up of 18 smaller hexagonal mirrors. They're made from beryllium coated with gold to optimize reflecting infrared light from the far reaches of the universe. It also has four scientific instruments, that help in imaging cosmic objects, and spectroscopy -breaking downlight into separate wavelengths to study the physical and chemical properties of cosmic matter.

The mirror and instruments are protected by a five-layer sun-shield, which looks like a kite and is built to unfurl to the size of a tennis court. Its membranes are made up of Kapton, which is known for its high heat resistance and stability under a wide temperature range. The Sun-facing side of the shield will get as hot as 230 degrees Fahrenheit (110 degrees Celsius), while the other side will be as low as -394F.

The telescope also has a “spacecraft bus” that hosts its subsystems for electrical power, propulsion, communications, orientation, heating and data handling; all told, Webb weighs around as much as a school bus.

2. It will be placed in Sun orbit, not Earth orbit

The telescope will be placed about a million miles from Earth in an orbit around the Sun. It will remain directly behind Earth, from where the Sun will be easily visible allowing it to remain on our planet's night side. Webb's sun shield will always be between the mirror and the sun.

It is expected that James Webb will take about a month to reach the designated region in space, also known as the second Lagrange point, or L2.

3. High-tech origami-style design

Since the telescope is too large to fit into a rocket's nose cone in its operational configuration, it is being transported folded in origami-style. Unfurling it will be a complex and challenging task. After 30 minutes from take-off, the communications antenna and solar panels supplying it with energy will be deployed and then the sun shield will start unfurled components. The membranes of the telescope will be guided by a complex mechanism involving 400 pulleys and 1,312 feet of cable.

4. Mission to find answers to fundamental questions of life, the universe, and everything

Webb's two primary scientific missions are to explore the early phases of cosmic history, looking back in time to only a few hundred million years after the Big Bang and the discovery of exoplanets- planets outside the solar system. It will investigate the potential for life in those worlds by studying their atmospheres.

5. It took decades to get ready

The debate on the telescope that can succeed Hubble Space Telescope began in the 1990s, while Webb's construction started in 2004. The launch has been pushed back several times, initially, it was scheduled for 2007, then 2018. And finally, it is being launched on Christmas 2021 eve.