The James Webb Telescope (JWST) is actually a space observatory. At first they called it Next Generation Space Telescope (NGST) , but in 2002 it was baptized with the name of James E. Webb, in honor of the US government official, NASA administrator (1961-1968) who played a fundamental role in the Apollo program. Let’s see what five other things you should know.
The huge primary mirror is the centerpiece of the James Webb telescope. It will be a concave structure 6.5 meters in diameter , made up of 18 smaller hexagonal mirrors, like a real puzzle. They are made of beryllium and coated with gold , specially designed to reflect infrared light from the ends of the universe.
The observatory houses four scientific instruments that, together, serve two main purposes: obtaining images of cosmic objects and the analysis of separate wavelengths using spectroscopy, to study the physical and chemical properties of cosmic matter .
A five-layer sunshade protects both the mirror and the instruments, shaped like a kite and the size of a tennis court once deployed. Continuing with safety, the membranes are composed of kapton , a material with high resistance to heat and great stability in a wide temperature range. Both properties are essential, because on the side facing the sun the temperatures will be 110 ºC and on the other side it will be -234 ºC.
The telescope will orbit approximately four times the distance from our planet to the Moon . Unlike Hubble, Webb will orbit the Sun.
It will remain behind the Earth, from the point of view of the Sun, what will be found on the night side of our planet. Webb’s parasol will always be between the mirror and the Sun. It will take more than a month to reach this region in space, known as the second Lagrange point (L2). While astronauts have been dispatched to repair Hubble, no humans have traveled to orbit at the L2 point.
The telescope is huge, too big to fit the nose of the Ariane V operationally. So it must be sent folded , like an origami, as many objects have already been sent into space, such as rovers on the Moon or Mars. Deploying the telescope will be a very complex task, to the point of becoming the most challenging deployment NASA has ever faced.
Approximately 30 minutes after takeoff, the communications antenna and the solar panels that power it will be deployed. On the sixth day and long after the Moon has passed, the parasol will begin to unfold, which remained folded like an accordion. Its thin membranes will be guided by a complex mechanism that involves no less than 400 pulleys and 400 meters of cable.
The mirror will open during the second week and for the final setup, the instruments will need to be cooled and calibrated. Mirrors will need to be adjusted very precisely. After six months of preparations, the telescope will be ready to go .
The James Webb Telescope has two main science missions . Between them they will occupy more than half the observation time. They will first explore the early stages of cosmic history by looking back in time to a few hundred million years after the Big Bang. Very close to the origin, if we take into account that the age of the Universe is 13,600 million years. At this point, astronomers want to see how the first stars and galaxies formed and how they evolved over time.
The second objective is the discovery of exoplanets , that is, planets outside the solar system. Along these lines, he will investigate the possibility of life on these worlds by studying their atmospheres.
The strength of the Webb telescope is based on the use of infrared. Unlike the ultraviolet and visible light in which Hubble primarily operates, the longer wavelengths of infrared penetrate dust more easily, allowing us to see the early cloud-shrouded universe more clearly.
Other secondary Webb targets are the closest observations in our solar system: Mars and Europa, Jupiter’s icy moon.
The debate for the construction of James Webb began in 1990, when a telescope was discussed to succeed Hubble. Construction of the Webb began in 2004.
The launch has been delayed several times , initially planned for 2007, then 2018, etc. The reasons are related to the different complexities of the project. Even during this month of December we have had several cancellations. The observatory as a whole is the result of strong international collaboration and integrates Canadian and European instruments.
More than 10,000 people have worked on the project. The budget eventually rose to around € 9 billion. The mission is scheduled to last at least five years , although it could be as long as 10 years or more.
The official NASA page for James Webb has a countdown to the launch of the mission. As it has had several postponements, we do not know if it will be reset again or, as they say on the twitter account, it will be launched before December 24.
Source: 5 Things to Know About The James Webb Space Telescope Before It Launches.
