Nasa’s $10bn James Webb Space Telescope struck by tiny meteoroids

The world’s most powerful telescope has survived a series of hits by small pieces of space debris since its launch in December

The first full-color image from Nasa's James Webb Space Telescope shows the galaxy cluster SMACS 0723. Photo: Nasa

This image made available by Nasa on March 16, 2022 shows star 2MASS J17554042+6551277 used to align the mirrors of the James Webb Space Telescope, with galaxies and stars surrounding it. The hexagonal shape of Webb’s mirrors and its filters made the shimmering star look more red and spiky. The first science images aren't expected until July 12. Photo: Nasa

This photo provided by NASA shows a “selfie” created using a specialized pupil imaging lens inside of the NIRCam instrument that was designed to take images of the primary mirror segments instead of images of space. (NASA via AP)

Webb is able to look back in time 13 billion years, a mere 100 million years after the Big Bang. AP

The James Webb Space Telescope separates from Arianespace's Ariane 5 rocket. AFP

Arianespace's Ariane 5 rocket, with Nasa's James Webb Space Telescope on board, takes off from the Guiana Space Centre in Kourou, French Guiana, on December 25, 2021. Reuters

The James Webb Space Telescope will help answer fundamental questions about the universe, peering back in time 13 billion years. AFP

Three decades and billions of dollars in the making, the world's most powerful space telescope will take up its position 1.5 million kilometres from the Earth. AFP

Nasa's James Webb Space Telescope is carried by rocket from Europe's Spaceport in French Guiana. AFP

This combination of images from an animation made available by Nasa shows the unfolding of the components of the James Webb Space Telescope. Webb is so big that it had to be folded origami-style to fit into the nose cone of the Ariane rocket. AP

Nasa’s $10 billion James Webb Space Telescope has been struck by tiny meteoroids four times since its launch in December, the US space agency has revealed.

Although the space observatory survived the hits, the most recent one in May was concerning because the micrometeoroid hit one of the telescope’s primary segments, which helps it “see” into deep space.

Nasa said such strikes from the tiny particles were unavoidable for spacecraft, which routinely sustained hits during their science missions.

“With Webb’s mirrors exposed to space, we expected that occasional micrometeoroid impacts would ... degrade telescope performance over time,” said Lee Feinberg, Webb optical telescope element manager at Nasa.

“Since launch, we have had four smaller measurable micrometeoroid strikes that were consistent with expectations and this one more recently that is larger than our degradation predictions assumed.

"We will use this flight data to update our analysis of performance over time and also develop operational approaches to assure we maximise the imaging performance of Webb to the best extent possible for many years to come.”

In a tweet, the space agency assured the public that the device "is still performing at a level that exceeds all mission requirements".

The telescope, which took more than 20 years to build, will be able to capture images more than 13.5 billion light years away and offer a glimpse into the birth of the universe.

The first science images taken by the observatory will be released on July 12.

Nasa said that Webb’s mirror was engineered to withstand bombardment from micrometeoroids, including particles flying at extreme velocities.

During its construction, engineers used simulations and actual test impacts on mirror samples to see how they can better protect the telescope in space.

However, the space agency said the most recent impact was larger than what it expected and “beyond what the team could have tested on the ground”.

Paul Geithner, technical deputy project manager at Nasa’s Goddard Space Flight Centre, said there were extreme conditions in space that the telescope would have to survive.

“We always knew that Webb would have to weather the space environment, which includes harsh ultraviolet light and charged particles from the Sun, cosmic rays from exotic sources in the galaxy, and occasional strikes by micrometeoroids within our solar system,” he said.

“We designed and built Webb with performance margin — optical, thermal, electrical, mechanical — to ensure it can perform its ambitious science mission even after many years in space.”

To protect the telescope, engineers can turn the mirror away from known meteor showers that are set to happen.

However, the most recent hit was not from a meteor shower and was deemed by Nasa to be an “unavoidable chance event".