In anticipation of its 2020 launch, NASA’s next-generation space telescope has just seen its first major environmental tests. The James Webb Space Telescope (JWST) recently underwent a mechanical shock test and an acoustic test, NASA announced in a May 4 news release.
The two environmental tests were performed solely on the JWST spacecraft element — which only includes the bus and sunshield, without the telescope’s optics and instruments — and were designed to assess how the spacecraft would handle the launching procedure and the harsh conditions in outer space.
Both types of tests are routinely performed on all spacecraft so that engineers can catch any potential issues in time and make sure all imperfections are fixed prior to launch, NASA pointed out.
As it turned out, the agency’s $8 billion space telescope did encounter a problem during the second environmental tests and came out a bit shaken in the end.
“Detailed inspections of the hardware after the acoustic test showed that fastening hardware that hold the sunshield membrane covers in place had come loose,” the U.S. space agency reported.
According to Space News, the dislodged items were discovered after the JWST spacecraft was moved last weekend from the acoustic test chamber into another testing facility, where it is set to undergo vibration testing.
“Right now, we believe that all of this hardware — we’re talking screws and washers here — come from the sunshield cover,” Greg Robinson, the JWST program director at NASA Headquarters, said during a meeting of the National Academies’ Space Studies Board organized in Washington D.C. on May 3.
“It’s not terrible news, but it’s not good news, either,” he added.
NASA is currently working on a recovery plan and already begun reviewing the test data and the spacecraft’s hardware configuration, Robinson noted in the news release.
“We expect to get back to the environmental test flow shortly and continue to move safely and methodically toward mission success,” he said.
The JWST spacecraft is presently housed by the NASA-hired contractor Northrop Grumman Aerospace Systems, in Redondo Beach, California. This is also where the two environmental tests were conducted and where the other half of the James Webb observatory, namely the telescope’s science payload, resides.
The acoustic test aimed to investigate how the JWST would fare under “the extreme sound and resultant vibration of the launch environment,” shows the NASA news release.
During the test, the spacecraft was subjected to sound frequencies ranging from 25 Hertz to 2,500 Hertz. At the same time, the JWST spacecraft was tested at loudness levels of up to 142.5 decibels — about three decibels higher than the levels expected during a rocket launch.
Meanwhile, the first spacecraft test simulated the mechanical shock that the James Webb observatory would have to endure when the payload adapter gets separated from the spacecraft after the launch.
The telescope’s spacecraft is scheduled for a third environmental test, which involves a vibration experiment intended to gauge whether it can withstand the intense shake of launch, NASA revealed.