Nasa’s James Webb Telescope arrives at its final destination – a million miles from Earth

The James Webb Telescope has successfully arrived at a gravitational stable point on the other side of the Earth from the Sun
The James Webb Telescope has successfully arrived at a gravitational stable point on the other side of the Earth from the Sun

The James Webb Space Telescope (JWST) has successfully arrived at its final position, one million miles from Earth.

Launched on Christmas Day, the $10 billion (£7.4 billion) telescope has now completed its vast journey after a month hurtling through space.

It will stay at its current position, Lagrange 2 (L2), for its entire operational lifespan, which is expected to be around 20 years. L2 is a gravitational stable point on the other side of the Earth from the Sun, where the pull of the two bodies cancels out.

Nasa initially expected Webb to operate for a maximum of 10 years, but its launch from French Guiana was so efficient that engineers now expect it to work for twice that.

“Everything has gone as smoothly as we hoped, but dared not expect,” said Professor Martin Barstow, chairman of the UK Space Agency’s Science Programme Advisory Committee.

“The launch was perfect, preserving thruster gas and allowing a much longer lifetime at L2 than expected.”

At 7pm GMT on Monday, Nasa’s engineers initiated a five-minute long course correction to delicately place JWST in its final position.

“Webb, welcome home!” said Bill Nelson, Nasa administrator. “Congratulations to the team for all of their hard work ensuring Webb’s safe arrival at L2 today.”

All that is left for the telescope to do now is to cool down. In a few months time, the telescope will become operational and start scanning the cosmos for the rays of infrared radiation emitted at the very dawn of the universe.

But, in order for this to happen, all other sources of infrared must be nullified, including any residual heat from the telescope itself. Once it reaches a frigid -223C, its 18 gold-plated mirrors will begin to analyse the dawn of time.

“We are now on the verge of aligning the mirrors, instrument activation and commissioning, and the start of wondrous and astonishing discoveries,” said Bill Ochs, Webb project manager at Nasa’s Goddard Space Flight Center.

Martin Ward, emeritus professor in physics at Durham University and co-developer of one of Webb’s four main instruments, added: “We must now wait for several months during which the instruments cool down, before, with great fanfare, the space agencies release the first spectacular images.”