The billion-dollar space telescope has been more than 20 years in the making will be its journey 1 million miles away from Earth.
But the reality is, despite decades of work and billions of dollars, a successful launch – assuming it goes according to plan – is still just the beginning of the final paragraph for the James Webb Space Telescope. It will not aim to orbit Earth like the venerable Hubble Space Telescope, but will fly directly to the Lagrangian point 2 (L2), a point 1 million miles away where the gravitational pull of the Earth and the Sun cancels out. , allowing Webb to orbit the Sun with our planet permanently in its rear.
Along the way, dozens of little things still have to work out just before NASA can officially begin scientific observations, and all of them must take place far from any human assistance in the cavity. the cold darkness of deep space.
Webb’s early hours— So you have successfully launched the rocket and it did not explode. Congratulations! The only additional dangers from here on out, starting with the launch of the Webb telescope into space, are:
- T + 27 minutes: If all goes well, this is when Webb will separate from the upper deck of the Ariane 5 launch vehicle, which provides thrust only for about 26 minutes after takeoff in French Guiana.
- T + 33 minutes: Webb will shrug off the Ariane 5 rocket and deploy its solar panels and start generating power. It’s an automatic action crucial to the telescope’s success – it doesn’t carry a nuclear power source like the Voyager deep space probes. Without solar power, it will quickly drain the battery.
- T + 12.5 hours: Webb fires up the first mid-lock correction engine to make sure it’s pointing in the right direction towards L2.
- T + 24 hours: Webb’s High Gain Antenna, organized in the Gimbaled Antenna Council, automatically positions itself to face Earth. This was the mission’s final automated deployment, with all other commands coming from human operators on Earth. The mission won’t necessarily fail if the antenna implementation fails, but it will greatly reduce the amount of data the mission can return at once.
Webb’s first week—
- T + 2 days: Webb started the second of three mid-course corrections.
- T + 3 days: Webb began the multi-step process of deploying its five-layer sunshade by opening the front sunshade, part of the Unitized Pallet Structure that holds the visor. Parts are spinning and heating up and preparing for the next steps of deployment. If all goes well, the rear sunshade pallet will be deployed within the same day. The two pallets fold outward and downward, forming with the Webb spaceship bus – the main frame or space frame – a plane perpendicular to the column formed by segments of mirrors still folded.
- T + 4 days: Webb’s mirrors and other components are raised two meters above the plane of the sunshades on the Deployment tower. This makes the sunroom fully deployable and will further insulate the telescope’s mirrors and instruments from the sun’s energy in the future.
- T + 5 days: Webb deploys its momentum smash. This is a reflection-controlled surface designed to resist the force of sunlight on a tennis court-sized sunshade. The reflective sunshade will naturally act like a solar sail and result in unwanted torque and other accelerations, but the pulsating momentum will reduce these effects to help keep the line of sight steady. Webb’s on the universe.
- T + 5 days: The protective visors in place on the sunshade from pre-launch have now been rolled up in preparation for the shield’s deployment.
- T + 6 days: The sunshade booms extend on both sides of the Webb bus, creating a diamond-like profile for the sun visor when the diaphragms open.
- T + 7 days: Webb begins a stretch process to stretch each of the five layers of the sunshade, completing the process on day eight.
Webb’s second week—
- T + 10 days: Webb’s secondary mirror moves from behind the Deployable Tower Cluster to its active position in front of the main mirror. It’s one of the most critical times in a telescope deployment – where a bad antenna can slow down the rate at which data can be sent home and solar panel failure can can scale down operations, a damaged secondary mirror will mean no images from Webb at all.
- T + 11 days: The rear unit’s heat sink, which is needed to keep the telescope’s sensitive infrared devices cool enough to see, deploys.
- T + 12 days: The left wing of the main mirror folds out and locks into place. Webb’s main mirror consists of 18 beryllium segments, but these segments are divided into a central section and two side wings, which are tightly folded into the center column for launch. Each wing contains three mirror segments.
- T + 13 days: The right wing of the main mirror folds out and into place, completing the full 21-foot diameter mirror and marking the full deployment of the James Webb Space Telescope.
But that’s not all she wrote – there were still weeks of travel and calibration before Webb could start doing any science.
Webb’s third week—
- T+15-24 days: Each segment of Webb’s main and side mirrors is adjustable via six actuators, and ground operators will spend days carefully aligning each segment to form a cohesive mirror system.
Webb’s fourth week—
- T + 29 days: The third, final and most important course correction takes place, sending Webb into orbit at point L2. One failed here and Webb headed straight into deep space.
- T + 29.5 days: After successfully orbiting at L2, the telescope’s main job for the next three weeks will be just cooling – scientific instruments need time to literally cool down. The telescope’s kit must reach minus 388 degrees Fahrenheit. To maintain the necessary sensitivity to the infrared spectrum.
Webb’s next five months— Once Webb is safely in orbit at L2, all of its components will be fully deployed, and its tools are as cold as hell. Can we do science yet?
Is not. The telescope’s mirror segments must be further aligned to ensure it can capture sharp images by focusing on a distant star, a process that will take about two weeks.
The mirror segments then had to be further adjusted, this time taking into account each of the four scientific instruments on the telescope, a careful effort by ground-based operators that took weeks. again.
Then, when the optics were finally aligned, months continued to test the device, making sure it could receive and process the mirror-focused image.
It’s Summer: Finally, We Can Science! – Final! All has gone well, things have settled down, and the journey of more than 20 years is finally over: Scientists can begin to use their time on Webb to image the faintest galaxies in the Universe, gazing at alien planets and even creating stunning images of planets in our solar system.
No earlier than mid-summer 2022.
https://www.inverse.com/science/whats-the-roadmap-for-james-webb-telescope-now What happened after the James Webb telescope was launched? Six-month roadmap