NASA's next-generation James Webb Space Telescope may have reached its final parking spot in space, but there is still a long road ahead for the observatory before it can start taking the dazzling pictures of the cosmos that scientists have been eagerly awaiting. In the next five months, mission engineers will test and modify the telescope in order to prepare it for the long term mission of observing the Universe.
The vehicle was put into its final position in space yesterday at around 2PM, when it fired its onboard thrusters for a little less than five minutes. It was the final step in the journey through the universe, capping off a 30-day voyage from the launchpad to its parking space. During that time, the telescope underwent a complex unfolding and shape shifting process to become its final form needed to collect light from distant stars and galaxies.
The observatory manager for the James said that the most riskiest part of the journey had come to an end. The best is yet to come.
In the next three months, mission engineers will align individual segments of the telescope's mirrors to make them work together like one mirror. The mission team will spend two months testing out the instruments and calibrating them.
It may seem like a long process, but in the grand scheme of the telescope's 25 years of development, it's just a few more months to wait before it changes astronomy.
The main mirror is 21 feet wide and stretching over 6.5 meters, making it the size of a coffee table. Too large to fit on any existing rocket, the mirror was built in segments that could fold in on each other. The team needs to align the segments precisely so they can create a seamless surface. The mirrors need to be aligned within 1/6th of a human hair in order to get a good view of the universe. It will take time to get them all in the right positions.
The mission team will begin by taking an image of a bright isolated star in the constellation Ursa Major. Engineers don't expect the picture to look very good.
The mission team will slowly adjust the position of each segment using motorized actuators on the back of each piece. The 18 blurry images should come together to make a clear image. The procedure is going to take a long time because the team will need to get data from the spacecraft and process the images before making the next adjustment.
Next week, mirror alignment should begin. The mission team needs the NearInfrared Camera to cool down. A type of light that is associated with heat is what the JWST is designed to see. In order to pick up the light, the main instruments have to operate at very cold temperatures. After launching from Earth, the JWST has cooled down a bit, but it needs to get even colder in the coming days so that NIRCam can start taking images.
The telescope's secondary mirror needs to be aligned with the primary mirror. The smaller mirror is in front of the gold- plated mirror on the black booms. The light gathered onto the four main instruments is directed by the smaller mirror.
Calibration of the telescope's instruments can be done with the fully aligned JWST. These include a combination of other imagers, cameras, and spectrographs, which break up light into different wavelengths on the spectrum. The mission team will test out each of the four main instruments over the course of two months. If that goes well, the first light images from the JWST will be released by NASA during a press conference. The next five months of tweaking, testing, and alignment should ensure that the images will be spectacular to behold.