At the end of 2021, the largest and most powerful telescope ever launched by mankind into space left the Earth. It took 25 years to create “James Webb”. All for the sake of an ambitious goal – to find life in the depths of the universe
Telescope development
“James Webb” has become the largest “space long-term construction” of our time. It took 25 years to build the telescope. Scientists from the US National Aeronautics and Space Administration (NASA), the European Space Agency (ESA) and the Canadian Space Agency (CSA) worked on it. The device cost $10 billion.
At first, the device was called the “Next Generation Space Telescope”, but later changed its mind. As a result, he received the name of the second head of NASA (in 1961-1968) James Webb. Formally, he was responsible for the implementation of the American program of manned space flights “Apollo”, although in fact the technical leadership was carried out by Wernher von Braun.
Webb aims to study distant objects in the universe, such as the first galaxies. Because their light is redshifted (outside “visible light”), the telescope needs infrared equipment. The device was equipped with a Near Infrared Camera (NIRCam), which is capable of not only capturing objects that mankind has never seen before, but also capturing 15 times more space than the camera of the predecessor of the Webb telescope, the Hubble telescope.
The new device received a mirror 6,5 m wide. For comparison, the Hubble had a size of 2,4 m in diameter. By increasing the mirror, the information collection area increased by 6,25 times. It turned out so big that it had to be divided into segments and folded to fit on board the launch vehicle.
The main mirror has become like a honeycomb – it consists of 18 beryllium segments that can work together or separately. Each part is covered with a layer of gold 100 nanometers thick. This metal was chosen because of its good ability to reflect infrared rays.
Why we need “James Webb”
Thanks to infrared equipment, Webb can look back in time 13,5 billion years ago. It will capture the objects in the universe the same as they were when they first appeared. If Hubble saw the “childhood” of the first galaxies, then the new apparatus will be able to look at their birth.
In addition, infrared equipment allows the telescope to look beyond visible light and look through massive clouds of dust and gas. First, it will allow us to study previously unseen objects and find where the first stars were born. Second, it will be able to look for life on exoplanets orbiting distant cold stars called red dwarfs.
“This is a time machine that will take us back to the very beginnings of the universe. We are on the cusp of incredible discoveries that we never imagined before,” said NASA chief Bill Nelson about the telescope. Scientists have high hopes for Webb: without it, it will not be possible to find out how and why stars, planets and other objects began to appear in space.
“Webb” will study not only the distant regions of the universe, but also the solar system. The main object of observation will be Jupiter, its ring system and two moons, Ganymede and Io.
Release
The launch of the Ariane 5 launch vehicle with Webb on board was preceded by a series of problems: the shipment was postponed several times. The reason was the unstable connection between the observatory and the rocket, the coronavirus pandemic, and bad weather. However, on December 25, 2021, the telescope nevertheless left the Earth.
“The Webb Telescope is a brilliant example of what we can achieve if we dream big. We always knew that this project would be a risky venture, but with great risk comes great reward,” US President Joe Biden tweeted, congratulating the launch participants. Dmitry Strugovets, head of the press service of the Russian state corporation Roscosmos, also noted the importance of sending a telescope into space: “Apparently, 2021 has become a breakthrough year for many projects that could not be launched in recent years.”
Immediately after the launch, Webb went to a distance of 1,5 million kilometers from Earth – to the second Lagrange point (L2). In this region, the gravitational fields of the Sun and the Earth cancel each other out, which allows the vehicle to remain stationary without wasting fuel. Before reaching its destination, the telescope must deploy a solar shield to protect it from the light of the Sun, Earth, and Moon. Without this five-layer membrane, it cannot work.
First results
On the third day of the flight to the L2 point, Webb successfully passed one of the most difficult stages of its space journey: using 90 cables and 107 descent devices, it deployed a heat shield. Then he deployed his main mirror, and within 30 days he reached his permanent location at the Lagrange point.
In early February, the telescope sent the first images back to Earth. He photographed his primary mirror and the sun-like star HD 84406. It is 260 light-years from the Sun. Since Webb took pictures with each segment of its mirror separately, which are not yet completely aligned, the result is a mosaic of 18 images. Now the scientists will adjust the mirrors for several months until the dots come together.
The star HD 84406 was chosen as a landmark because there are no such bright objects nearby. Researchers 156 times changed the position of “Webb” in space, trying to direct it in the right direction. It took the telescope six hours to “catch” the star in each segment of the mirror. In total, the observations took scientists 25 hours.
In addition to the photo of the star, the telescope took a “selfie” of the mirror. The picture was taken thanks to an additional lens inside the infrared camera. One of the segments is overexposed because it was aimed at a space object. “Selfie” was needed by scientists to clarify the location of the segments of the mirror.
The resulting images confirmed that the NIRCam was able to receive light normally and that no equipment was broken. “The entire Webb team is delighted with how well the first steps in capturing and setting up the telescope are going. We were so happy to see the light coming into the NIRCam camera,” said researcher Marcia Riquet.
It remains for scientists to align all the segments of the mirror and wait until they cool down to an operating temperature below 50 Kelvin. Full adjustment of the telescope will take about six months. After that, “James Webb” will be ready for full-fledged exploration of the depths of space.