When the James Webb space telescope occupies its final position, in the second of the Lagrange points – a region where it can remain stationary with respect to the Sun and the Earth -, 1.5 million kilometers from our planet, it will become one of the most valuable scientific tools built to date for the study of the cosmos.
This device has a 6.5 meter diameter primary mirror – it will be the largest in space – made up of 18 segments made of beryllium and covered by a layer of gold, and its main mission will be to search for the light emanating from the first stars and galaxies, and provide data on their evolution, the formation of planetary systems and the origins of life.
To do this, its instruments will observe in near and mid infrared, a range of wavelengths that will allow it, for example, to see through clouds of dust and gas and to capture the phenomena that take place inside them and to study the atmospheres of the extrasolar worlds in search of molecules that are often related to biological processes, such as water, methane, oxygen or carbon monoxide and dioxide.
The launch of the telescope was scheduled for October 2018. However, in a recent statement, NASA has announced that it will finally take place between March and June 2019 , and that the James Webb will take off from the European space base in Kourou, in French Guiana, aboard an Ariane 5 rocket.
A very complex project
Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate, has clarified that the delay is not due to hardware or technical performance problems . The point, he says, is that the integration of some of the elements of the ship is taking longer than expected. According to Zurbuchen, this adjustment will not affect the budget – the development of the space telescope, an international project in which the European Space Agency and Canada participate in addition to NASA, has already cost 8.8 billion dollars – or the project’s objectives. In fact, it ensures that the analysis and tests of the instruments are being satisfactory.
“The spacecraft itself and the shield that protects its equipment from solar radiation and prevents it from interfering with its sensors are large and complex structures, and some tasks, such as the installation of more than a hundred release devices in this protective membrane are taking more than anticipated, “said Eric Smith, program director James Webb.
The aforementioned shield is one of the most striking pieces of the observatory and constitutes an audacious work of engineering. It is made up of five sheets of kapton, a heat-resistant polymer, arranged one on top of the other and a few centimeters apart. This configuration achieves a rapid reduction in temperature, so that between the outermost layer, that is, the one most exposed to the Sun, and the innermost layer, the one closest to the primary mirror, it goes from 84 ºC to 230 under zero.
In search of life
One of the first targets this space telescope could focus on is the planetary system of TRAPPIST-1, an ultracool dwarf located just 40 light-years from Earth. Since its find was announced in the journal Nature in 2016, seven rocky worlds , like Earth, have been located around it. Apparently, three of them are in the habitable zone, a region in which the presence of liquid water on its surface is possible and, with it, the existence of life. Recent studies show that the star’s intense magnetic activity may have made it difficult to emerge, but even so, many astrobiologists believe this matter is worth investigating. ” If these bodies have atmospheres, the James Webb telescope will be essential to unveil their secrets, ” says Doug Hudgins, one of the people in charge of NASA’s exoplanet study program.
Images: ESA / NASA – JPL – Caltech -T. Pyle (IPAC)
