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NASA’s $ 10 billion James Webb Space Telescope has had a tough encounter with an alien danger: it has been hit by a micrometeoroid.
The micrometeoroid strike does not appear to have significantly altered Webb’s vision, nor has it rendered him incapable of making revolutionary observations of the universe, including the capture of light emitted more than 13 billion years ago, near dawn of time. The telescope, launched from French Guiana on Christmas Day, is still being calibrated and, according to all accounts, has worked splendidly.
But the direct hit of a mirror caught NASA by surprise and is still being analyzed. Details of the micrometeoroid attack were revealed by NASA in a blog post dedicated to Webb.
“Between May 23 and 25, NASA’s James Webb Space Telescope suffered an impact on one of its primary mirror segments,” the NASA Webb Block said. “After initial assessments, the team found that the telescope still operates at a level that exceeds all mission requirements despite a marginally detectable effect on the data.”
The 18 segments of the mirror can be individually adjusted in response to meteoroid impacts like this, NASA said.
“By adjusting the position of the affected segment, engineers can cancel some of the distortion … although not all degradation can be canceled that way,” the NASA blog said. “Engineers have already made a first such adjustment for the recently affected segment … and the planned additional mirror adjustments will continue to fine-tune this correction.”
The exact size of the micrometeoroid is unknown. It may not be bigger than a grain of sand, said Heidi Hammel, a long-time planetary astronomer who has been involved with the telescope. and we will use it to study our solar system. Even something so small can cause damage because of the sheer speed with which the telescope orbits the sun and periodically collides with a random particle.
This was a known danger, because even though he is lonely in space, he is not as empty as he seems.
“There is no loss of science from this event.… This telescope is in space; we knew there would be tiny impacts. We were surprised that once so soon,” Hammel said.
He said scientists had predicted this impact every five years or so, on average.
This extraordinarily complex observatory, heralded as the long-awaited successor to the still-functioning Hubble Space Telescope, is orbiting the sun in a position that keeps it approximately one million miles from Earth. It is too far away for astronauts to visit and is not designed to be fixed or instruments changed.
Webb has been going through a “commissioning” phase for months, as its instruments are calibrated and the 18 gold hexagonal mirrors line up to function as a single massive mirror about 21 feet in diameter.
So far, NASA has reported nothing but success.
“Astronomers are dizzy about how things are going (but also nervous about not doing it, we can be superstitious too) and eager to start doing science!” Astrophysicist Michael Turner of the University of Chicago said in an email.
The telescope, folded over itself during launch last year, blossomed over many days as its sun shield opened and mirrors unfolded. The telescope traveled for 29 days to reach its advanced location, an orbital position known as L2 where other telescopes have operated safely and provided scientists with data on the frequency of micrometeoroids.
“While the telescope was being built, engineers used a mixture of simulations and actual test impacts on mirror samples to get a clearer idea of how to fortify the observatory for its orbit operation. This most recent impact was more much of what was modeled, and beyond what the team could have tested on the ground, “NASA’s Webb blog said.
Webb is different from most telescopes: it is wide open, with mirrors exposed instead of tucked into a tube. The telescope is designed to observe the universe at infrared wavelengths that are out of Hubble’s detection range.
This requires very cold mirrors and instruments, that is why mirrors are oriented at all times away from the Earth and the sun. NASA has announced that the “first light” images will be released on July 12, but has not said what they will show.
However, it has already produced an image of a star, used to focus mirrors. At the bottom of this image are numerous galaxies whose light was emitted billions of years ago, and this has thrilled astronomers who expect Webb to see deeper into space (and the past) than Hubble, launched in 1990.
Webb has multiple purposes, including studying the oldest light in the universe, emitted hundreds of millions of years after the big bang. It will also study the evolution of galaxies and study objects in our own solar system, including small, icy bodies that orbit the sun far beyond Neptune’s orbit.