James Webb Space Telescope: Where Is It Now?

Three issues ago, I wrote an article describing James Webb: a space telescope capable of seeing billions of years into the universe’s past. Named after one of NASA’s former administrators, construction on the telescope began in 1996, with a planned launch in the year 2007. Due to technical problems, budget limits, and extensive delays, Webb wasn't launched until December 2021. Now, it’s about five months after the observatory’s launch, and Webb is getting closer to sending back observational images of neighboring stars, galaxies, and galaxy clusters.

You may ask, “Why is it taking so long for Webb to begin operations?” This is because of several factors, including the time it takes for it to travel to its observational destination, as well as the countless maneuvers and tests that must be performed on Earth by NASA to make sure it's functional. Webb’s destination is the second Lagrangepoint (according to NASA, a Lagrange point, named after 18th century mathematician Joseph-Louis Lagrange, is an orbiting point where the Earth, Moon, and Sun’s gravities create a fixed gravitational field), which is about one million miles away from Earth. It took Webb about 30 days to reach the second Lagrange point.

After its arrival at the Second Lagrange Point, Webb had to undergo a series of tests and maneuvers, including the unfolding of its sun shield and the realignment of its 18 mirrors. Such a process is meticulous, as telescope operators need to make sure all parts of the telescope are functional and in their proper positions to begin taking photos. Scientists then took an experimental photo to test the mirror arrangement, and they were successful! However, the mirror alignment process also requires the cooling of many of its components to extremely cold temperatures to prevent heat from interfering with the infrared photography, which takes over a month.

The telescope is currently – at the time of this article’s writing – on its last mirror alignment stage, the final cooling MIRI stage. According to NASA, in this stage, the telescope’s near-infrared instruments are operational at their required low temperatures, but the Mid-Infrared Instrument cannot be cooled to its necessary temperature by space alone. Using helium gas, the telescope is cooling MIRI to its operational temperature of 7 degrees Kelvin, which is almost absolute zero. After this stage, all mirrors will be corrected for the last time, and the instruments will be tested one last time before images are taken. Hopefully everything goes well, and within the next few weeks, we should be seeing James Webb’s images!