NASA's Time Machine, James Webb Space Telescope will be historic

The most exciting thing in cosmology is about to happen. We might be on the edge of finding the answer to the biggest question in science: Are we alone in the universe? Let's find out with NASA's Time Machine, James Webb Space Telescope.

Image Source: NASA

 
NASA's $10 billion time Machine, the James Webb space telescope will be historic. It's Nestled atop an Ariane Space Ariane 5 rocket, the James Webb Space Telescope rolled out to the launch pad at Europe’s Spaceport in Kourou, French Guiana. JWST will study every phase of the cosmos—from our solar system to galaxies formed 13.5 billion years ago, just after the Big Bang. A colossal collaboration between NASA, the European Space Agency, and the Canadian Space Agency, Webb will revolutionize our understanding of the universe.

The James Webb Space Telescope, also called Webb or JWST, is the largest space telescope in history, and it's optimized for infrared wavelengths. It will complement the Hubble Space Telescope’s abilities, and extend our discoveries of galaxies, and exoplanets that could have life.

The Hubble Telescope created a revolution in astronomy and raised new questions that required a new, different, and more powerful telescope to be built. The Webb telescope is 100 times more powerful than the Hubble and will have a longer wavelength coverage, and greatly improved sensitivity over any other previous space telescope. This is why some scientists call it a time machine. Because the longer wavelength coverage will allow the telescope to look further back in time to find the first galaxies and stars that formed in the early universe.

Helping with this incredibly difficult task is the lightweight, deployable primary mirror, which is 2.7 times larger in diameter than Hubble’s mirror. That’s about 6 times larger in area. The mirror is made of a special material called Beryllium, which has a high strength-to-weight ratio. This will give the JWST more light-gathering power over other space telescopes.

These special beryllium mirrors are coated with a super-thin layer of gold that is about 1000 atoms thick to optimize their reflectivity in the infrared spectrum. The entire amount used to coat all the mirrors is a little more than the mass of a golf ball [48.25 grams of gold]. Unlike the Hubble Space Telescope, the James Webb Space Telescope will operate much farther from Earth, allowing it to achieve an extremely cold operating temperature, stable pointing, and the JWST will have a much higher observing efficiency than the Earth-orbiting Hubble.

The JWST is designed to detect near-infrared and mid-infrared wavelengths. This is the light beyond the red end of the visible spectrum, which is invisible to the human eye.

The James Webb Space Telescope will have a mission lifetime of around 10 years, and that life is ultimately limited by the amount
of fuel, the telescope needs to maintain its orbit and the proper function of the spacecraft itself and its instruments.

The high-tech infrared detectors need to be cooled with liquid helium to prevent thermal fluctuations from swamping the astronomical sensors. Because the helium will gradually be used up, this expensive telescope only has a short mission life of 5.5 to 10 years. So chances of it operating beyond this will depend on a manned spaceflight, which could happen 10-years from now, but there is nothing planned as of yet.

This brings us to the next point. The launch of the James Webb Space Telescope will be a huge leap of faith for humanity and our technological capabilities.

The reason is that JWST will be operated at the second Sun-Earth Lagrange point, which is located approximately 1.5 million kilometers away from the Earth. This means it cannot be repaired or serviced, including refilling its liquid helium tank, after reaching its destination, and will be beyond the reach of any currently planned crewed space vehicle.

Some have asked why Webb cannot be assembled and tested in Earth’s orbit, but this was studied and found nearly impossible to pull off.

The International Space Station and its crew do not have the capabilities to assemble precision optical structures in orbit.

There is also the problem of space junk and debris, considering that China and Russia recently blew up satellites in space. This floating debris could damage or contaminate the expensive telescope's optics. Not only that but if the space station were used as a stopping point, another rocket would be needed to launch Webb to its final destination, and the observatory would have to be designed with much more mass to withstand a second launch.

It’s fragile enough as it is. The James Webb Telescope is bigger than the Hubble, with the most important thing being the diameter of the primary mirror, which is made up of 18 hexagonal segments and stretches 6.5 meters [21-feet wide] from top to bottom, with its total area measuring slightly more than 25 square meters.

That is a little more than half of what Hubble weighed on Earth.

The largest structure of the JWST is its sun shield, which protects the deployed primary mirror, and the tower that holds the secondary mirror, which is also made of Beryllium and is gold-coated. It will be farther from the heat of the Sun, Earth, and Moon, its open design and special heat shield will keep it cool enough for its infrared detectors to work properly. Even infrared radiation from the telescope itself can cause problems. But the liquid helium cooler onboard will take care of that.

All warm bodies and objects emit infrared radiation, even you and me. Being able to observe in infrared light wavelengths means the Webb can detect more distant and older objects in the universe.

Now the JWST will communicate with scientists on Earth using a high-frequency radio transmitter. NASA’s Deep Space Network, which consists of large radio antennas, will receive the signals, and those will be sent to the Webb Science and Operation Center at the Space Telescope Science Institute in Baltimore,
Maryland USA.