In a mission spanning more than two decades, NASA on Saturday launched the most expensive science probe ever built, a $10 billion telescope that will attempt to capture starlight from the first galaxies to be born in the fiery crucible of the Big Bang. .
Billions behind budget and time, the James Webb Space Telescope finally got off the ground on Christmas Day, atop an Ariane 5 rocket at 7:20 a.m. from the European Space Agency’s launch site in Kourou, French Guiana.
The workhorse European booster, built by Arianespace as part of ESA’s contribution to the Webb project, put on a spectacular holiday show, racing through a cloudy sky off its wilderness launch site on the northeast coast of South America .
Accelerating through the sound barrier 47 seconds after liftoff, Ariane 5 quickly exited the dense lower atmosphere, shedding its two strap-on solid-fuel boosters along the way.
Arianespace
The first stage’s single hydrogen-fueled Vulcan 2 engine shut down eight and a half minutes after launch, and flight continued for 16 minutes on the power of the rocket’s cryogenic second stage.
Then, 27 minutes after launch, at an altitude of about 865 miles off the east coast of Africa, the James Webb Space Telescope was released flying outward at more than 21,000 mph.
“Go on, Web!” said a mission controller to thunderous applause from the team.
Still folded to fit inside Ariane 5’s nose cone, the observatory’s single solar panel, which is critical to starting recharging the spacecraft’s batteries, was deployed at computer command about six minutes after separation. has gone. An on-board thruster is scheduled to be fired Saturday night to fine-tune the trajectory.
NASA TV
“This is a great day not only for America, for our European and Canadian partners, but for planet Earth,” said NASA Administrator Bill Nelson, speaking to Kennedy Space Center.
Congratulating the thousands of men and women who built and launched the telescope, he said, “You have all been incredible and for more than three decades you have built this telescope that will now take us back in time.”
“It’s a time machine, it’s going to take us back to the beginning of the universe,” he said. “We’re going to discover incredible things we never imagined.”
Webb will take a full month to reach its orbital parking spot from Earth, a million miles from the Moon’s orbit — known as Lagrange Point 2 — where it can orbit the Sun in gravitational lockstep with Earth, Provides the cold, dark environment necessary for mission success.
The telescope has been adapted to capture images of the first stars and galaxies to shine after the Big Bang, the light that has spread from the expanse of space into the infrared part of the spectrum over the past 13.8 billion years.
That light cannot be seen by the iconic Hubble, which Webb will eventually replace. Hubble was designed to study visible light wavelengths, but nonetheless, it has detected galaxies dating back to within half a billion years after the Big Bang.
Webb should be able to extend back several hundred million years, detecting the light that began to shine out when the universe was only 200 million years old or more. This is the era when the universe first emerged from the hydrogen fog of birth and starlight began to travel freely in space.
AP. via NASA
Pictures of the long-expected baby of the universe are expected to shed revolutionary light on the formation and evolution of galaxies, the supermassive black holes lurking at their hearts, and the life cycles of stars, from birth to titular supernova explosions that ripened through the period. Most of the elements in the table.
Closer to home, Webb will also study the atmospheres of planets orbiting nearby stars to characterize their habitability and extend beyond Mars to the distant Kuiper Belt beyond Neptune to Earth’s solar system. Get a regular, close-up look at the planets, moons, asteroids and comets in the circle.
Lagrange Point 2 is far out of reach of any visionary astronaut repair crew, but it is an ideal location to achieve the ultra-low temperatures needed to detect infrared emissions from the infant universe.
But orbit alone is not sufficient to cool Webb to the required 50 degrees or above absolute zero.
For the telescope’s 21.3-foot-wide primary mirror and its four sensitive instruments to detect that scorching heat, Webb must first spread a sunshade the size of a tennis court to block the light and thermal emissions of the Sun, Earth and . Moon.
The more than 100 electrically-activated mechanisms used to keep the sunshade’s five hair-thin Kapton layers in place during the start of the launch’s vibration and weightlessness, all must open flawlessly so that the membrane ejects onto the boom as planned Can go
Then each layer must be pulled taut and separated by motorized cables running through dozens of pulleys.
If this all sounds complicated, it is. If that sounds unusually risky, it is.
“Sun Shield is where so much of the deployment risk exists because that’s where many single point failures exist, and it’s complicated,” said deputy project manager Paul Geithner.
“We have 107 small non-explosive actuator devices, membrane release devices … That’s where deployment is so much of a risk because it’s a lot of parts. They’re simple mechanisms, but there are a lot of them and they All the work has to be done.”
Deployment of Sunshade is expected to start from December 28 and if all goes well, the process will be completed by January 2.
Next comes the deployment of Webb’s 21.3-foot-wide segmented primary mirror, the largest mirror ever built for an instrument in space. Like the sunshade, the mirror had to be folded to fit inside the Ariane 5’s nose cone.
About 10 days after launch, six of the mirror’s 18 hexagonal sections, three on each side, will fold up and lock into place. Each segment can be tipped and tilted to achieve razor-sharp focus, a process that would take months to complete.
Throughout the deployment and commissioning process, Webb will continue its slow cool-down to reach the operating temperature it requires. If all goes well, the first science images are expected about six months after launch.
“All these single point failures, all these deployment mechanisms that go right to make the telescope, there’s no half-stage,” Mark McCogreen, senior advisor for science and exploration for the European Space Agency, said in an interview with Spaceflight. Now.
“If the sunshield is only half-deployed, the telescope never cools down, the instruments won’t turn on. So that’s nerve-wracking time, that first month. And after that, five months of getting cold and on, and then we can Let’s start doing science.”
,
