On October 12, NASA's $10 billion James Webb Space Telescope finally reached the European Spaceport in Kourou, French Guiana, on the north coast of South America, after a 16-day, 9,300-kilometer sea voyage.
It is scheduled to launch on December 18 to send it into space. The launch site is close to the equator and the Earth rotates faster, providing more momentum and saving fuel for the rocket.
The next step will be to install the James Webb Space Telescope into a 5-meter diameter fairing, launched by an Ariane 5 rocket provided by the European Space Agency, and deployed to the second Lagrange point 1.5 million kilometers from Earth.
There, the horizons of the Earth, the Sun and the telescope are always in a certain relative position, and the light shield can be effective without frequent position correction, and the gravity is relatively stable relative to the position of the neighboring celestial body, which can be observed more stably, and will not be affected by the dust near the Earth's orbit.
The James Webb Space Telescope is an infrared space telescope named after NASA's second director, James Webb, who led a number of important U.S. space exploration programs, including the Apollo program. Developed by NASA, the European Space Agency and the Canadian Space Agency, the main contractor is Northrop Grumman, and development began in 1996.
Originally planned to cost $500 million and launch in 2007, the project was significantly overspended for various reasons, with several delays in launch times and current development costs exceeding $10 billion. It is the fifth largest space program for mankind after the Space Shuttle, the International Space Station, the Apollo Moon Landing and the GPS Satellite Navigation System.
The Spitzer Infrared Telescope has a mirror diameter of only 0.85 meters, hubble telescopes are 2.4 meters, and James Webb telescopes reach 6.5 meters. This will give the telescope unparalleled resolution, and a coin can be seen from 40 kilometers away. This size exceeds the size limit of the rocket launch, so the option is to process it into 18 identical hexagons, fold it up and unfold it.
The mirror material adopts alkaline earth metal beryllium material with high bending stiffness, good thermal stability, high thermal conductivity and low density, which is an extremely important metal in the military industry and the core material of navigation equipment for intercontinental missiles. The processing accuracy of the mirror surface requires an error of no more than 10 nanometers, and each lens can also adjust the angle at will, and the adjustment accuracy does not exceed 10 nanometers, and 10 nanometers is only equivalent to the width of dozens of beryllium atoms placed together.
The James Webb Space Telescope, which can detect the faint light of distant stars and galaxies, can detect the light emitted by the first generation of galaxies formed in the early universe, and its main task is to investigate the residual infrared evidence of the Big Bang theory (cosmic microwave background radiation), that is, observing the early state of the universe visible today, which will help us explore the mysteries of the solar system, explore the distant worlds of other stars and the origin of the universe.
For this purpose, it is equipped with a high-sensitivity infrared sensor, a spectrometer, etc. In order to facilitate observation, the body should be able to withstand extremely low temperatures, but also to avoid sunlight and earth reflections, etc., for this telescope comes with a foldable blackout plate to shield the light source that will become interference.
The sunshade of the James Webb Space Telescope has five layers, each only 25 to 50 microns thick, and the area after unfolding is about 300 square meters, equivalent to a tennis court. The heat of the mirror device itself and the external heat source will produce infrared interference, and the sunshade can protect the telescope from any heat source that may interfere with the line of sight, so that the telescope can work at a very low temperature of about minus 273 ° C, in order to detect the weak heat signal of distant objects in the universe.
The James Webb Space Telescope studies the atmospheres of nearby exoplanets in search of habitable environments, and finds and analyzes Earth-like planets in the distant universe. When the Webb telescope focuses on a star surrounded by a known planet, and the planet orbits from the front, the telescope detects a slight decrease in brightness. This will first help us to calculate the size of the planet, while observing the degree of brightness decline from different wavelengths will give us more information. Because atoms and molecules absorb different wavelengths of light, measuring the degree of dimming with a particular wavelength of light can reflect what kind of molecules exist in the planet's atmosphere.
If the telescope detects attenuation at wavelengths of 1.15 and 1.4 microns, we can know that water vapor is present in the planet's atmosphere because water molecules absorb light in large quantities in these two bands. Weber will be able to observe a wide range of wavelengths of light, from visible to mid-infrared, which is useful for observing several common molecules on Earth, such as carbon dioxide, oxygen and nitrogen.
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