What’s next for the largest observatory on Earth?
The new observatory, which is the largest ever built space telescope, successfully unfurled its last primary mirror segment on Saturday, Jan. 8. This was the culmination of what NASA called one of the most difficult deployments in space history. Now, the Webb mission team will focus on directing the telescope towards its final destination and getting important parts of the observatory online to support its astronomy work.
Webb will arrive at its “insertion spot” by Jan. 23. Once it is in place, Webb will fire its engines to glide towards Earth-sun Lagrange Point 2 or L2. This “parking spot”, which is approximately 930,000 miles (1 million kilometers) from our planet’s surface, will be ignited. Webb can stay in the same place for as long as it is in the correct zone thanks to its near perfect alignment with the sun and Earth.
The control teams must execute more than just maneuvers in space. Webb has many complex commissioning tasks ahead of him. NASA highlighted the importance of aligning the mirror and getting its instruments ready for launch as milestones to be aware of in the coming weeks.
Webb is preparing for the engine fire. Team members will spend the next fifteen days aligning the mirror segments so that they “essentially perform like one mirror.” John Durning (Webb’s deputy project manger at NASA’s Goddard Space Flight Center), spoke to reporters Saturday, Jan. 8, in a press conference held from Webb’s control center at Space Telescope Science Institute, Baltimore, Maryland.
Durning said that Webb would turn on the instruments within the next week. “And then, once we get into L2, the instruments get cold enough for them to start turning on the different instruments.
The telescope can see through young exoplanets
Webb’s ideal place to do its work is L2. Webb can work in darkness due to its distance from the sun. A sunshield is also required in order to make heat-seeking infrared observations. The telescope will be able to see through dust objects, such as young exoplanets or the interior distant galaxies in its quest for understanding the universe’s evolution.
NASA says Webb has four science instruments. These instruments will allow Webb to observe in visible, near and mid-infrared wavelengths (0.6 to 28.5 millimeters), according to NASA.
Durning stated that each instrument has its own set of milestones. It will be difficult to calibrate them once they reach temperature.
In a press conference, Lee Feinberg, Goddard’s manager of the optical telescope element at Goddard, explained that mirror deployment will begin on Tuesday, January 11. Feinberg stated that the mirrors were folded to withstand the stress of launch. It will take between 10-12 days to get all the mirrors in the right position for detailed optical alignment.
It will take three months to align the basic elements. The telescope will then take its first test image during the alignment process. NASA warned that the first images of the telescope will likely be blurry as it is still being aligned. The configuration will require more testing and imaging.
Durning stated that the telescope should be aligned by day 120. This date would depend on how the commissioning process progresses.
He said that instrument commissioning will take place in parallel with other instrument team partners. They will “turn on different instruments and then [will] use these instruments to align and refine the telescope.”
History can be sensitive about blurry images coming from space telescopes. The Hubble Space Telescope was famously launched in 1990 with some myopia and had to be corrected because of an engineering error. Hubble is located in low-Earth orbit and can be accessed by astronauts aboard the space shuttle to perform repairs or upgrades. Webb is too far away to do such work, so remote calibrations are required.
Jane Rigby from Goddard’s Webb operations project scientist, said that mirrors are started at millimeters. Then, we drive them to align to within less than a coronavirus size, to tens or nanometers.
It’s a deliberate and time-consuming process. Let’s be clear: the first images we take with the telescope are not taken right out of the box. It’s going to look ugly. It will be blurry. It will be blurry. We’ll have 18 images scattered across the sky.
Rigby said, “I like to see it as we have 18 mirrors right now, little prima donnas doing their own thing singing their own tune in whatever key they are in,” Rigby added. “We must make them sing like a chorus. That is a tedious, methodical process.”
Rigby stated that the team will be releasing a series of “wow pictures” to showcase the telescope’s capabilities after commissioning is over. Although the first targets are not yet available to the media Rigby stated that the team plans to release a set of “wow images” to showcase all four scientific instruments and to truly amaze everyone.
Officials stated during the press conference that the first images would include stars (to verify alignment) as well as the Large Magellanic Cloud (to evaluate the telescope’s ability render shades of luminosity or inherent brightness).
After commissioning, which will take approximately six months, will be a preliminary period of five months of science operations. This will consist of “early-release science programs”, which are six categories of work that range from stellar physics to planet formation.