In the vacuum of space, the telescope is cold, but it likes the extreme environment it was designed for.
Present in the vacuum of space since the beginning of the year, the James Webb Space Telescope is closely scrutinized by NASA teams, they who have taken decades to design this telescope at the maddening cost of more of $10 billion. Repeatedly postponed, the “Webb” mission finally saw the light of day on December 25, from the European base of Kourou in French Guiana.
Over the past few months, everything has gone well for NASA, which has seen the telescope deploy and position itself around Lagrange Point 2 without issue. The American space agency even recovered a little fuel on the way, which made it possible to extend the duration of the mission. For a few weeks now, the JWST has been circling around the Lagrange point, right in the heart of space.
A more than polar cold
In the absolute vacuum an icy cold reigns, close to absolute zero (-273.15°C). This theoretical temperature is not actually achievable, but it is the ultimate limit set by the laws of current physics. An extreme temperature which the telescope, which was designed to operate in this extremely cold environment, must nevertheless approach.
NASA explains that the James Webb must be kept away from all possible heat sources, at a stable temperature of -233°C, an ideal situation for the proper functioning of the device. In order to limit the sources of heat as much as possible, the telescope therefore has a huge sun visor, protecting it from the heat of the sun’s rays.
If this temperature of -233°C should be reached without the help of the telescope’s cooling tools, the fourth instrument on board the James Webb, the MIRI, requires even more work for NASA, which must lower the spectrometer infrared as well as the camera at -266°C.
New milestone for NASA
To do this, NASA would have to use a cryocooler, a system that sends cold helium gas to the elements to cool them. If the maneuver has already started for two weeks, NASA expects to receive interesting results in the coming weeks, while the gas should expand, and therefore, still cool.
A very important step for NASA, which expects a lot from MIRI. This device should be able to capture the light of the first stars in the history of the Universe, billions of years ago. Such data will then make it possible, after analysis in laboratories on Earth, to better understand the first “hours” of the history of the Universe, thus validating the Big Bang theory.