In the midst of the COVID-19 shutdowns, many things are uncertain during these turbulent times. The team at Northrop Grumman located in Redondo Beach, CA has begun limiting the number of people working on the James Webb Space Telescope testing procedures. Even with the reduction in personnel the James Webb Space Telescope just met a significant goal.
The James Webb Space Telescope will be the successor of the famous Hubble Space Telescope. According to NASA, once successfully launched into orbit Webb will be the premier observatory. Webb will provide thousands of astronomers access to new information about our universe never before obtainable. Equipped with a smorgasbord of revolutionary technology the Webb telescope will be able to observe stellar objects up to 13 billion light-years away. Early formed galaxies on the outskirts of the universe will be just one of the many areas of study of the mission.
In order to collect enough light to accomplish these observations Webb’s designers equipped the telescope with a 6.5 meter mirror. The team working on the mirror’s design faced the challenge of managing the massive mirror’s weight. If designed similar to Hubble’s mirror it would be too heavy to be launched. The mirror was created using beryllium which is light but also very strong. A very thin layer of gold coats the face of each mirror.
The primary mirror consists of eighteen hexagonal-shaped individual pieces. Hexagon were chosen as they have a high filling capacity, meaning they fit together nicely. They also have a six-fold capability which allows the mirror to fold into a small enough shape to fit in the spacecraft for launch. The 18 hexagons are divided into 3 groups depending on the optical prescription. In order to focus the mirrors actuators are used for adjustment of curvature and alignment.
The mirror is required to maintain temperatures around 50 degrees Kelvin or -220 Celsius. This allows the telescope to observe mid-infrared light radiating off far away and very faint objects. It will also have the capability to observe visible orange and red light as well as ultraviolet.
Webb will be sent very deep into space in order to maintain this frigid temperature. It will be placed approximately 1,500,000 kilometers away from earth, this is almost 4 times more than the distance of the moon. During the mid-infrared imaging, a cryocooler will help with the cooling of the instrument. Webb is equipped with solar shields to block the sun’s heat and separate the mirror from the other components.
Several months ago the team successfully deployed the five-layer sun shield that sits beneath the mirror. The success of the mirror deployment is another link in the chain of success the Webb has been having after a long history of roadblocks.
A major concern with Webb was the mirror deployment. The sheer size of Webb’s mirror prevents it from fitting into the Ariane 5 rocket for launch. In order to circumvent this issue, it was designed to fold for transport to space. Upon deployment into orbit, the mirror will be unfolded. This portion of the mission is crucial. If the mirror does not deploy properly the telescope would not be capable of capturing light properly. The distance from the earth when in place in orbit around the sun would prevent a manned mission for repairs. This recent success of the mirror’s operation is a big step towards getting Webb into space.
The team used gravity compensation supports attached to the telescope in order to simulate the conditions Webb will experience in space.
Mirrors are the primary optical device on space telescopes. The larger they are the more sensitive they are. This sensitivity to light collection allows for incredible imaging of very distant objects.
Webb’s scheduled launch date is still listed as March 2021, however, due to the recent Coronavirus shutdown, NASA will be suspending further testing for the time being. The next portion of the scheduled work is the installation of the deployable tower assembly prior to the 2021 launch in French Gauna. Upon completion, testing will be suspended indefinitely due to the lack of crucial NASA personnel present during the limited operations.
The COVID-19 shutdowns are affecting the country as a whole. These shutdowns, though necessary, have thrown the proverbial wrench into the gears of the scientific community. This may delay the launch once again. However, astronomers are a patient group and seeing how the Universe has been around for 14 billion years, I suppose another delay might not do too much damage to the research.