NASA’s James Webb Space Telescope (JWST) finally launched on December 25 after a slow gestation process that began way back in 1996. While the launch was a complete success, there are many more phases of the telescope’s journey and deployment that remain incomplete and that need to go off without a hitch before NASA, its cooperating space agencies and the wider scientific community and public can breathe a sigh of relief. Thankfully, with the wonders of modern technology, NASA has made it possible for anyone who is keen to see the mission succeed follow as the adventure of the JWST unfolds, quite literally, in real-time.
NASA’s “Where is Webb” website features a live, data-driven infographic that shows the stats of the JWST (or just “Webb” as insiders call it), as it makes its way to its orbital position, some 1 million miles (1.5 million km) from Earth. As many of you will have guessed already, that puts it well out of Earth’s orbit where the Hubble space telescope has been orbiting at an altitude of around 570 km and out into deep space. The Webb’s orbital insertion point is known as the second Lagrange point (L2). This orbit will place the telescope in line with the Earth as it orbits the Sun. This position was selected as it, in conjunction with the Webb’s sunshield, will provide maximum protection from the light and heat of the Sun, Earth and even the Moon. [NASA]
The JWST Will be Fully Deployed on Arrival at the L2 Orbit
The “Where is Webb” site is currently plotting every step of Webb’s journey including the various deployments of its components that it has either already undertaken or will undertake and roughly when each of these critical phases will take place. With a mirror that measures 21 feet across (6.5 meters), the Webb had to be designed so that it could be folded to first fit into its launch vehicle. In this case, the Webb needed to be tucked tightly inside the European Space Agency’s Ariane 5 rocket, which has a payload fairing that runs 18 feet wide (5.4 meters). This is what has necessitated the complex unfolding and deployment process that the Webb is currently undertaking.
Once the sunshield is fully deployed, the mirror segments will then begin unfolding and locking into place to complete its dish. This will begin from around day 10 and last through to day 26. At the time of writing, the Webb was over three days into its mission as was roughly 37 percent of the way towards the L2 orbit. It had successfully deployed its Aft Unitized Pallet Structure (UPS), which carries the five folded sunshield membranes. In total, NASA says 140 release mechanisms, 70 hinge assemblies, 400 pulleys and 90 cables need to work flawlessly or the $10 billion project could come to naught.
To ensure that the Webb is properly aligned for orbital insertion, it will be firing its maneuvering rockets along the way to fine tune its trajectory. The “Where is Webb” site tells us that on day 29 of the mission, the Webb will complete its final “burn” as it is inserted into its L2 orbit [NASA]. At that time, the “Where is Webb” side will naturally stop tracking distance, but will switch to monitoring the Webb’s temperatures in real-time.
The Webb will need to cool to operating temperatures of around -370 degrees Fahrenheit (-233 degrees Celsius) and will begin a battery of tests and calibrations that will last several months before it begins to send its first images back. At that point, prepare to be blown away. If you didn’t understand what all the fuss has been about, you certainly will as the Webb has imaging capabilities that are up to 100x more powerful than the Hubble. This is powerful enough to “see back in time” to the formation of the first stars in universe. The Webb is more than just another telescope — it is a virtual time machine.