A Comparison of the Evolution of Infrared Space Telescopes | TechNews

The Large Magellanic Cloud is a satellite galaxy orbiting the Milky Way. The Webb Space Telescope team compared the Webb Space Telescope (see top image)’s Mid-Infrared Observatory (MIRI), the Wide-field Infrared Survey Explorer (WISE), and the Spitzer Space Telescope (SST) ) of the Large Magellanic Cloud image, the team said: the main mirror of the Wide Field Infrared Survey Satellite is only 40 cm, the main mirror of the Spitzer Space Telescope is 85 cm, and the main mirror of the Webb Space Telescope is 6.5 meters, compared to The lower part is much larger, and the resolving power and light-gathering power are also much better. In addition, the Hubble Space Telescope cannot provide images in the mid-infrared band.

▲ Large Magellanic Cloud. (Source: Universe Today)

Astronomers and engineers seem to be stunned by the Webb Space Telescope’s resolving power, but readers may be surprised to learn about the telescope’s capabilities from ground tests before launch? The team’s scientist Marshall Perrin explained that they did test the entire optical system in Houston’s cryogenic environment, but ground-based testing is challenging and, unlike the space environment, doesn’t actually tell us the final state of performance. For example, the primary mirror of the Webb Space Telescope is designed to have a certain shape in zero gravity, but it is unavoidable that it will deform due to gravity in ground tests, and it needs the assistance of computer numerical models. Moreover, there is no way to test on the ground whether the instrument will vibrate due to the spacecraft in space. In addition, the vacuum chamber at the Jensen Space Center can reach the cryogenic temperatures of the Webb Space Telescope in space, but some factors contribute to the inaccuracy of the test.

While ground-based testing has practical utility, it will ultimately take space to show results. The team expects the first official images to be released in July.

(This article is reproduced with permission from the Taipei Planetarium; source of the first image: NASA/MSFC/David Higginbotham/Emmett Given, Public domain, via Wikimedia Commons)