The James Webb Telescope is currently undergoing testing. The telescope consists of the Integrated Science Instrument Module (ISIM), the Optical Telescope Element (OTE) and the Spacecraft Element (Spacecraft Bus and Sunshield). Scientists are testing the ISIM’s ability to withstand frigid temperatures and the electromagnetic environment of space.
The James Webb Telescope is the most powerful telescope to date and specializes in the infrared spectrum so that researchers can study images of the Universe’s oldest stars and galaxies. The ISIM contains four light-detecting instruments that will measure light from these distant planets, including a near-infrared camera, near-infrared spectrograph, mid-infrared instrument and fine guidance sensor/near infrared imager and slitless spectrograph.
Not only must the telescope remain operational for five to ten years, but it must also be able to withstand the vibrations from the launch. This requires multiple tests and overcoming obstacles before the launch date in 2018.
The Types of Tests Facing the James Webb Telescope
Scientists must confirm that the James Webb Telescope can handle the temperatures and electromagnetic emissions found in space. Recently, the telescope passed a series of electromagnetic emission and acoustic and vibration tests.
The electromagnetic emission testing occurred at NASA’s Goddard Space Flight Center in Maryland. Scientists took electromagnetic emission measurements from the ISIM and from the rest of the spacecraft to avoid electromagnetic interference. The walls of the lab minimize reflections to give researchers an accurate reading.
Since the telescope passed this test, scientists can confirm that any objects reported from the telescope while in space are not from electromagnetic interference.
The acoustics and vibrations tests were also conducted at Goddard Space Flight Center. In order to fit into the rocket for the launch, scientists will fold the telescope. These tests are imperative to ensure the instruments can manage through the noise and vibration of the launch while in this folded state.
NASA engineers placed the telescope in a 42-foot tall chamber, known as the Acoustic Test Chamber. After subjecting to a sound level of 150 decibels for a series of two-minute tests, the telescope passed inspection in the clean room.
Moving Past Obstacles
In December of 2016, the James Webb Telescope experienced an anomaly that caused engineers to halt furthering testing for a few weeks until the investigation was over. During a vibration test, the ISIM’s launch restraint mechanism began to move with small motions. This particular restraint keeps the telescope’s mirrors folded during the launch. The movement was small, but enough to shut down the test for a fraction of a second.
Unfortunately, even subtle movements can sabotage a launch. Scientists temporarily stopped the testing until the results came back and corrected the issue. Testing resumed in January of 2017 and engineers will test the telescope’s vibration stability in the remaining two dimensions.
The Remaining Tests Before Launch
The telescope is on schedule for remaining cryogenic tests at NASA in Houston, Texas. Temperatures in space so far from Earth equal minus 387 degrees Fahrenheit and the James Webb Telescope needs to operate for up to 10 years in this environment. The cryogenic test takes place in a thermal chamber.
After the telescope passes the final round of cryogenic testing, it will move to California for integration with the Spacecraft Element of the James Webb Telescope for sunshield testing. These tests will confirm the integrity of the Kapton, thin layers of temperature-resistant material used to guard against the sun’s rays, as well as other heat-resistant elements.
The James Webb Telescope is an international project with NASA, the European Space Agency and the Canadian Space Agency. The Hubble Telescope’s successor will launch in October of 2018 on the Ariane 5 Rocket and begin observations as early as April 2019, approximately one million miles from Earth. If the new telescope continues surpassing all of the remaining tests, it won’t be too long before astronomers can see some of the first galaxies and stars created.