Free Astronomy Magazine March-April 2022

5 MARCH-APRIL 2022 But enough about its time here on Earth − with the cost overruns, crit- icisms, and controversies surround- ing its development, fabrication, testing, naming, and launch all ac- counted for over its 25-year his- tory, NASA and its collaborators (the European Space Agency, Canadian Space Agency, and several academic and industrial organizations) have successfully launched what is ar- guably the most important tele- scope ever deployed in the history of space science. Now in a halo orbit around the Sun- Earth L2 (second Lagrange) point, a distance 930,000 miles (1,500,000 km) from Earth, the James Webb Space Telescope (JWST) has been de- livered, unfurled, and unfolded. It is currently in the process of cooling down before calibration, where it will perform minute adjustments to its 18 hexagonal mirror segments to make the now-famous honeycomb- shaped array act as a single mirror. These adjustments are performed by actuators capable of motions as small as 10 nanometers – 1/10,000 th the width of a human hair and a fraction of the wavelengths of light that Webb was designed to detect. The alignment process will take three to five months to complete be- fore the telescope is officially ready to start doing the data collection its developers and proponents have been waiting so long to begin. If all goes well, Webb observation time is expected to begin this summer. In the meantime, mission special- ists will have to be content with HD 84406, a 6 th magnitude star in Ursa Major this is being used for alignment and data collection purposes. In terms of scientific discov- ery, the expectations are great. The JWST can de- tect objects 100 times fainter than those observed with the Hubble Space Telescope (HST), itself A rtist conception of the James Webb Space Telescope. [Adriana Manrique Gutierrez, NASA Animator]