The most delayed telescope in history is about to experience its moment of truth. It will be our best eye on the universe: the most sophisticated space telescope in the world will be like a ‘time machine’ that will see how it all began, by tracking the first lights that originated in our universe after the Big Bang.
A time machine’
One of the oldest mysteries concerns how the first light originated in pure black space just after the Big Bang. Astronomers hope to advance their understanding thanks to the fabulous capabilities of this telescope. Its power would allow astronomers to witness the puzzling past of our universe. One of the goals is to look back in time 13.5 billion years to see the first stars and galaxies that formed , a few hundred million years after the Big Bang. We are eager to get answers to some questions about the origins of our universe.
How long will it take to be operational?
For starters, it will take about 30 days for the James Webb Space Telescope to travel 1.5 million kilometers to where it will find its permanent home: a Lagrange point, a gravitationally stable location in space. Specifically, James Webb will orbit the Sun at the second Lagrange point (L2) , opposite the Sun, allowing the telescope to stay in line with Earth as it orbits our star. It was also the home of Herschel (which ran out of coolant in 2013) or the Planck Space Observatory , which also shut down in 2013 after spending almost 5 years studying the remnants of radiation from the Big Bang and the evolution of stars).
An origami telescope
Because it’s too big to fit entirely into the rocket’s nose cone, the telescope will travel folded up, like origami. The deployment will be the most difficult NASA has ever attempted. Approximately 30 minutes after arrival, the communication antenna and solar panels will be straightened. Then comes the deployment of the solar shield. Its thin membranes will be controlled by a complex mechanism that includes 400 pulleys and 400 meters of cable. In the second week, the mirrors will open, and after this the instruments will cool down and calibrate.
How will you observe the universe?
The James Webb Telescope will mainly observe the universe in the infrared, while Hubble, its worthy successor, has examined it since its launch in 1990, mainly in optical and ultraviolet wavelengths. Webb has a much larger light-gathering area, allowing it to look at greater distances and thus further back in time than Hubble.
How will it stay cool and working properly?
Scientists have created a huge five-layer heat shield that reflects as much sunlight as possible and protects the layer below it. If it were in low Earth orbit, the infrared heat emitted by the Earth would prevent it from reaching the necessary low temperatures. The parasol is gigantic: 21.2 meters long and 14.2 meters wide. Each layer has a “hot side” that faces the Sun and a “cold side” that faces the telescope. The outermost layer, directly exposed to the Sun, will reach a temperature of 85ºC, and the innermost layer will remain at around -233ºC. The telescope needs to be kept at a very low temperature to operate properly.
