The James Webb Space Telescope is going to go to space in December of 2021. Astronomers hope to find the first galaxies to form in the universe with it, and will look for Earthlike atmospheres around other planets.
The Conversation with NASA/Desiree Stover.
I am an astronomer and the principal investigator for the NearInfrared Camera, or NIRCam. I have been involved in the development of my camera and telescope.
To see into the universe, the telescope must be kept very cold. Getting a piece of equipment like this to space is not easy. We had to overcome many challenges to design, test and launch the most powerful space telescope ever built.
The telescope needs to be large and kept very cold in order to detect the most distant and oldest galaxies. NASA/Chris Gunn.
Young planets and alien atmospheres.
The telescope has a mirror over 20 feet across, a tennis-court sized sun shade to block solar radiation, and four separate camera and sensor systems to collect the data.
It works like a satellite dish. The light from a star or a galaxy will bounce off the primary mirror and into the NIR cam, which takes images in the near IR, and the Near IR, which splits the light from a selection of sources into their colors.
Scientists will be able to study how stars form in the Solar System and the atmospheres of planets outside it. It is possible to figure out the composition of the atmospheres.
The NIRCam will measure the light from distant and old galaxies. NASA/Chris Gunn.
Astronomers have been asking how old the oldest galaxies are since Hubble's discovery. How did they form? How have they changed over time? The First Light Machine is the name of the telescope that is designed to answer these questions.
One of the main goals of the telescope is to study distant galaxies. It takes billions of years for the light from these galaxies to reach Earth. I think we can show protogalaxies that were just 2% of their current age, when we collect images with NIRCAM.
Finding the first aggregations of stars that formed after the Big bang is a difficult task because they are very far away.
The mirror of the Hubble Space Telescope can collect less light than the one of the Webb mirror. The telescope must be able to focus the light on the distant objects in order to see them.
The telescope has to deal with the fact that the universe is expanding and that the galaxies that scientists will study with the telescope are moving away from Earth. The wavelength of light from distant galaxies shifts down from visible light to IR light when the ambulance's sirens start to sound.
The five layers of silvery material underneath the gold mirror reflect light and heat to keep the sensors incredibly cold. NASA/Chris Gunn.
It is a giant heat telescope. The telescope needs to be very cold if it is to see faint galaxies in the light. The heat shield is here. The shield is made of plastic. It is five layers thick and will keep the mirror and sensors at minus 395 degrees Fahrenheit.
How does one get a telescope that is so complex to work in space?
Engineers and scientists tested the telescope in a vacuum chamber. NASA/Chris Gunn.
Prepare and test.
The International Space Station is close to Earth, but the James Webb Space Telescope is far away and too far away to be serviced by astronauts.
The team has tested the telescope and instruments over the past 12 years, shaking them to make them feel like they were in a rocket launch. Everything has been tested under extreme operating conditions. I will never forget the time my team was in Houston testing the NIRCam in a chamber designed for the Apollo lunar rover. Even though Hurricane Harvey was fighting us outside, we couldn't have been happier that my camera detected light that had bounced off the telescope's mirror.
Rehearsals and training at the Space Telescope Science Institute are important to make sure that the assembly process goes smoothly. NASA/STScI.
Rehearsals came after testing. The telescope will be controlled using a radio link. It takes six seconds for a signal to go one way because the telescope is so far away. For the past three years, my team and I have been going to the Space Telescope Science Institute in Baltimore and running rehearsal missions on a simulation covering everything from launch to routine science operations. The team has practiced dealing with potential problems that the test organizers throw at us.
To fit inside a rocket, the telescope needs to fold into a small package. NASA/Chris Gunn.
Some alignment is required.
After the launch date in December, the team will continue to rehearse and practice, but their work is not done.
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We need to wait 35 days for the parts to cool. The mirror segments will be snapped by NIRCam with high-resolution images. The telescope team will analyze the images and tell the motors to adjust the segments. We will confirm that the telescope alignment is perfect once the mirrors are in position. If one of the two copies of NIRCam fails, the other can take over the job.
The process of alignment and checkout should take six months. When finished, he will start collecting data. Astronomers have been working on a telescope for 20 years to peer into the farthest reaches of the universe.
The Conversation is a news site that shares ideas from academic experts. It was written by a University of Arizona professor.
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NASA gave funding toMarcia Rieke. The Heisings-Simon Foundation funded her endowed chair.
