BALTIMORE — As commissioning of the James Webb Space Telescope nears completion, project officials and NASA management promise that the first images from the telescope will amaze scientists and the public.
During a media event at the Space Telescope Science Institute (STScI) here on June 29, project leaders and scientists said the telescope was already collecting “early scatter observations” that NASA, as well as the Space Agency European Union and the Canadian Space Agency, will unveil on July 12. These observations come as engineers finish preparing the telescope for routine scientific observations, with 15 of its 17 observing modes now in operation.
JWST’s technical performance continues to exceed expectations. Lee Feinberg, head of the JWST Optical Telescope Elements at NASA’s Goddard Space Flight Center, that the telescope required its resolution to be diffraction limited – that is, its sharpness limited only by the laws of physics – at wavelengths as short as 2 microns. He said the telescope actually had diffraction limited to 1.1 microns.
Feinberg attributed this technical performance to several factors, such as attention to detail during its development and extensive testing. “We knew how important this observatory was. It is potentially the largest and most complex science mission NASA has ever built,” he said.
“As a systems engineer, I made sure we had a headroom, a performance headroom, that we can rely on,” said Mike Menzel, JWST Mission Systems Principal Engineer at NASA Goddard.
This margin, he and others say, helps improve performance now and ensures that it can meet its specifications even as systems degrade over time. One example is a micrometeoroid impact on a mirror segment in May that was larger than engineers had modeled when developing the telescope.
“Time will tell whether or not this last impact was just an anomaly,” Menzel said. However, he downplayed the significance of the impact, noting the large margin in the telescope and the strategies the mission is developing to mitigate those impacts. “Even after this last impact, the telescope is performing beautifully.”
While JWST was designed for a 10-year operational lifespan, Pam Melroy, NASA assistant administrator, said engineers confirmed the precise launch provided by the Ariane 5 rocket last December had saved the fuel originally intended for course corrections, allowing it to operate on Earth. -sun L-2 point for 20 years.
Scientists are preparing for the upcoming release of initial scientific observations, which will include images and color spectra. These observations “will demonstrate to the world that Webb is, in fact, ready for science, and that he is producing excellent and spectacular results,” said Klaus Pontoppidan, JWST project scientist at STScI. “It’s also about highlighting the breadth of science that can be done with Webb and highlighting the four scientific instruments.”
Project scientists kept the list of objects confidential for these initial observations. “It took a long process to get to what the first images would be,” he said, based in part on what regions of the sky the telescope could observe when it was ready for those first observations. “We knew we needed a very long list of targets: more than 70 in the end. This process created a priority list of observations when the telescope instruments were ready.
Although the list remains secret, NASA officials have hinted which will be released on July 12. NASA Administrator Bill Nelson, attending the event by phone after testing positive for COVID-19 the night before, said one would be “the deepest image of our universe that has ever been taken”, better than various “deep field” observations by the Hubble Space Telescope.
“It’s further than humanity has ever looked before,” Nelson said. “We are only beginning to understand what Webb can and will do.” Pontoppidan confirmed that scientists will release the deepest infrared image of the universe to date, but did not quantify its comparison with past deep-field images.
Thomas Zurbuchen, NASA associate administrator for science, said the publication’s first observations will also include spectra of an exoplanet, which can help scientists determine the composition of its atmosphere. “We can’t wait to see the atmosphere of this specific planet and many more,” he said.
Both Melroy and Zurbuchen said they have already seen some of these images which will be released during the July 12 event. “What I saw moved me,” Melroy said, “as a scientist, as an engineer, and as a human being.”