The world’s most powerful space telescope on Saturday blasted off into orbit, headed to an outpost 1.5 million kilometres from Earth, after years of delays caused by technical hitches.
“We have liftoff,” declared the announcer on the live broadcast by Nasa. “From a tropical rainforest to the edge of time itself, James Webb begins a voyage back to the birth of the Universe.”
The James Webb Space Telescope, three decades and billions of dollars in the making, left Earth aboard an Ariane 5 rocket from the Kourou Space Centre in French Guiana at 7.20am local time (7.20pm Thailand time).
Twenty-seven minutes later, it separated from the rocket and began a month-long journey to its remote destination, during which time mission controllers have to perform several extraordinarily complex and delicate manoeuvres to keep it on course.
The telescope is expected to beam back new clues that will help scientists understand more about the origins of the Universe and Earth-like planets beyond our solar system.
Named after a former Nasa director, Webb follows in the footsteps of the legendary Hubble telescope — but has been designed to show humans what the Universe looked like even closer to its birth nearly 14 billion years ago.
Speaking on social media, Webb project co-founder John Mather described the telescope’s unprecedented sensitivity.
“JWST can see the heat signature of a bumblebee at the distance of the Moon,” he said.
All that power is needed to detect the weak glow emitted billions of years ago by the very first galaxies to exist and the first stars being formed. (Story continues below)
An Arianespace Ariane 5 rocket, with the James Webb Space Telescope onboard, launches from the Guiana Space Center in Kourou, French Guiana on Saturday. (Nasa Photo via Reuters)
‘Exceptional measures’
The telescope is unequalled in size — it weighs 6.3 tonnes — and complexity. Its mirror measures 6.5 metres in diameter — three times the size of the Hubble’s mirror — and is made of 18 hexagonal sections.
It is so large that it had to be folded to fit into the rocket. That manoeuvre was laser-guided with Nasa imposing strict isolation measures to limit any contact with the telescope’s mirrors from particles or even human breath.
To protect the delicate instrument from changes in pressure at the separation stage, the rocket-builder Arianespace installed a custom decompression system.
“Exceptional measures for an exceptional client,” said a European Space Agency official in Kourou.
Once James Webb reaches its final position, the challenge will be to fully deploy the mirror and a tennis-court-sized sun shield.
That intimidatingly complex process will take two weeks and must be flawless if Webb is to function correctly.
Its orbit will be much farther than Hubble, which has been stationed 600 kilometres above the Earth since 1990.
The location of Webb’s orbit is called the Lagrange 2 point and was chosen in part because it will keep the Earth, the Sun and the Moon all on the same side of its sun shield.
The special orbital path will keep Webb in constant alignment with Earth as the planet and telescope circle the sun in tandem.
Astronomical operation of the telescope, to be managed from the Space Telescope Science Institute in Baltimore, is expected to begin in June 2022, following about six months of alignment and calibration of the mirrors and instruments.
It is then that Nasa expects to release the initial batch of images captured by Webb, though scientists are keeping mum about where precisely they plan to point the telescope first.
Webb, which is designed to last up to 10 years, is expected to profoundly transform scientists’ understanding of the Universe and our place in it.
It mainly will view the cosmos in the infrared spectrum, allowing it to peer through clouds of gas and dust where stars are being born, while Hubble has operated primarily at optical and ultraviolet wavelengths.
Closer to the Big Bang
Astronomers say Webb will be able to bring into view a glimpse of the cosmos never previously seen — dating to just 100 million years after the Big Bang, the theoretical flashpoint that set in motion the expansion of the observable universe an estimated 13.8 billion years ago.
Hubble’s view reached back to roughly 400 million years following the Big Bang, revealing objects that Webb will be able to re-examine with far greater clarity.
Aside from examining the formation of the earliest stars in the universe, astronomers are eager to study super-massive black holes believed to occupy the centres of distant galaxies.
Webb’s instruments also make it ideal to search for evidence of potentially life-supporting atmospheres around scores of newly documented exoplanets — celestial bodies orbiting distant stars — and to observe worlds much closer to home, such as Mars and Saturn’s icy moon Titan.
The telescope is an international collaboration led by Nasa in partnership with the European and Canadian space agencies. Northrop Grumman Corp was the primary contractor. The Arianespace launch vehicle is part of the European contribution.
Webb was developed at a cost of $8.8 billion, with operational expenses projected to bring its total price tag to about $9.66 billion, far higher than planned when Nasa was initially aiming for a 2011 launch.