At the end of August, the tests on the James Webb Space Telescope were successful be completed. This means that nothing stands in the way of the telescope planned as Hubble’s successor. And so the new star-gazing tool from Nasa, Esa and CSA (Canada) will be launched into orbit from the spaceport in French Guiana on December 18th. Most of the launcher is already on site, but the telescope still has to be transported to the launch site.
James Webb: A History of Many Setbacks and Delays
The telescope during the assembly phase. (Source: Nasa)
The last delay was just one more in a long series of setbacks. After all, the development of the James Webb telescope had already started in 1996. The telescope was originally supposed to go into service in 2007.
In the course of the conceptual design, however, its developers discarded a large part of their work. In 2005 they revised the equipment. The original start time could no longer be kept.
James Webb telescope should close gaps in Hubble observations
The James Webb Space Telescope is the designated successor to the Hubble telescope, which was only recently rescued with some effort and which essentially works with the technology of the 1980s. The latest payloads, such as the Wide Field Camera 3, which repeatedly delivers spectacular images, were added in 2009 and are therefore already 12 years old again.
Although the James Webb is the successor to the Hubble space telescope, its special skills partly in other areas. It has a much larger mirror and focuses on observations at lower frequencies in the mid-infrared range. This should enable it to track down early galaxies that even Hubble cannot find.
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In this respect, the analyzes to be expected based on the James Webb observations are urgent required additions to existing Hubble data. There are some large gaps here, which we hope can now be closed. The telescope relies on the mid-infrared spectrum because infrared waves are more likely to be able to penetrate cosmic dust. In addition, they represent the primary radiation from cooler celestial bodies such as brown dwarfs and planets.
Prioritization raises the bar of technical challenges
This setting of priorities explains some of the technical challenges. The instruments of the new telescope must be permanently cooled to minus 220 degrees Celsius in order to avoid interference with infrared measurements. To achieve this, the operation of the James Webb requires both a large sun shield and an operation near the second Lagrange point between the sun and earth. It will be deployed around 1.5 million kilometers from Earth while Hubble is in a near-Earth orbit.
Unlike Hubble, the James Webb needs fuel to stay on course. This drastically shortens the service life of the telescope. Nasa is assuming a useful life of around five years, but is hoping for ten.
