Why NASA's James Webb Space Telescope will operate in orbit nearly 1 million miles from Earth
THE REASON NASA PUTS THE JAMES WEBB SPACE TELESCOPE IN ORBIT NEARLY 1 MILLION MILES FROM EARTH WAS ALL ABOUT KEEPING THE TELESCOPE IN A LOW TEMPERATURE ENVIRONMENT.
This is an artistic illustration of the NASA James Webb Space Telescope space station that will stay in space at the second Lagrange point of earth and day, which from the sun's point of view is directly behind the Earth. (Source: Northrop Grumman)
NASA's James Webb Space Telescope will be more extreme than its famous predecessor in many ways, including its cosmic position.
The $10 billion Weber Space Telescope is larger, more complex and more powerful than the Hubble Space Telescope, which has been studying celestial objects in Earth orbit for more than 30 years.
It will also fly farther afield – the second Lagrange point (L2) of the Earth-Day towards Mars ( in the direction of the Non-Solar ) , which is about 930,000 miles (1.5 million kilometers ) from our Earth.
Lagrange points are gravitational stabilization points, where spacecraft can more or less "stay" and can maintain the same relative position without consuming too much fuel. But the Webb telescope went to the second Lagrange point not to preserve the propellant, but to maintain a low temperature there.
The Weber telescope was able to observe the universe using infrared (IR), a long-wavelength electromagnetic wave that has a thermal effect (in contrast, Hubble shoots primarily in the visible and ultraviolet wavelengths). In order to receive the weakest infrared signal, the Weber telescope's scientific instruments must remain extremely low, so the telescope has a five-layer visor that, when fully unfolded, will be the size of a tennis court.
However, if the visor is turned away from the sun, it cannot provide the necessary protection, and the role of the second Lagrange point is revealed.
"What's special about this orbit is that it keeps the telescope in line with the Earth as it orbits the sun," NASA staff wrote in an article explaining the second Lagrange point.
They added: "This allows the satellite's huge sun visor to protect the telescope from light and heat from the sun and earth (and the moon). "That's why the telescope is set at the second Lagrange point."
If all goes according to plan, webb's instruments will work around minus 370 degrees Fahrenheit (minus 225 degrees Celsius). Meanwhile, solar panels, communications antennas and other non-scientific devices in the higher parts of the Webb telescope will be around 185 degrees Fahrenheit (88 degrees Celsius).
"The temperature difference between the hot and cold sides of the telescope is very large - you can almost boil water on the hot side and freeze nitrogen on the cold side!" NASA staff wrote.
The distance at which the Weber telescope was placed at the second Lagrange point highlights another key difference from Hubble. The old-fashioned Hubble telescope was designed to serve astronauts who spacewalked, and they made five repairs and upgrades to the hub between 1993 and 2009. The first of these missions was particularly important, fixing a flaw in hubbell's main mirror that caused the telescope's initial images to be very blurry.
But the second Lagrange point is 930,000 miles from Earth, so it is impossible to send astronauts over, so the Webb telescope — whose main mirror is 21.3 feet (6.5 meters) long, almost three times as wide as Hubble — will operate alone at the second Lagrange point.
Diagram of the Relationship between Lagrange Points and the Earth-Sun System (Source: NASA/WMAP Science Group)
The Webb telescope needs to reach its destination 30 days after launch. Once in orbit at the second Lagrange point, the Webb telescope will rotate around that point and perform a full inspection, rather than simply staying on it. After that, the telescope will begin a rich observation activity that has never been seen before. The Webb telescope will study some of the earliest stars and galaxies in the universe, sniffing the atmospheres of nearby exoplanets, looking for signs of possible life, and many other missions.
The Webb telescope is not the first spacecraft to stop at the second Lagrange point. Also running there are NASA's Wilkinson Microwave Anisotropy Probe Telescope (from 2001 to 2010), the European Space Agency's Herschel Space Telescope (2009 to 2013) and planck probe (2009 to 2013).
A number of other probes have worked at the first Lagrange point of Earth-Sun, 930,000 miles from Earth toward the Sun. These include the Solar and Heliosphere Explorer in cooperation with NASA and the European Space Agency, and the Deep Space Climate Observatory in cooperation with NASA by the National Oceanic and Atmospheric Administration.
There are a total of five Lagrange points, and although L3 is in a straight line with L1 and L2, it is on the other side of the sun. L4 and L5 are in Earth orbit, 60 degrees in front of and 60 degrees rear of the Earth, respectively.
BY:Mike Wall
FY: Landodo
If there is any infringement of the relevant content, please contact the author to delete it after the work is published
Please also obtain authorization to reprint, and pay attention to maintaining completeness and indicating source
Selected Articles: Astronomical Volunteer Essay Group-
Translation: Astronomical Volunteer Article Group - Landodo
Review: Astronomical Volunteer Article Group-
Final Review: Astronomical Volunteer Article Group - Zero Degree Galaxy
Typography: Astronomical Volunteer Article Group - Zero Degree Galaxy
Aesthetics: Astronomical Volunteer Essay Group-
Resources
1. WJ Encyclopedia
2. Astronomical terms
3. The original text comes from: https://www.space.com/james-webb-space-telescope-why-distant-orbit-l2
This article is translated by the Astronomical Volunteer Article Group - Landoduo from the work of mike Wall, the author of the article, if there is any infringement of related content, please contact the author to delete it after the work is published.
Note: All the information data is huge, it is inevitable that there will be errors, and please also welcome to the readers Haihan and welcome Axe.
End, thank you for reading and interested
Full text typesetting: Astronomy Online (Zero Degree Galaxy)
Please obtain permission to reprint, and take care to maintain integrity and indicate source
The vast universe is infinitely vast And the beauty of the dome can be seen from the bottom of the sky