As the James Webb Space Telescope allows astronomers to peer into large, distant galaxies, it’s also learning about other smaller objects nearby – even if they don’t realize it.
These are micrometeoroids, tiny meteoroids solar system with lightning speed. They’re too small for scientists to observe directly in deep space, but they shouldn’t be ignored: Micrometeoroids can carry debris, just like NASA. James Webb Space Telescope (JWST or Webb) can prove. Since JWST’s launch in Christmas 2021, engineers have observed more than 20 micrometeoroid impacts on the telescope; only one that clearly hurts the viewer. The project is adjusting its operations to reduce the rate of micrometeoroid strikes, but even so, the impacts themselves may be unexpected data from the new power station.
“It’s actually a tool for meteoroid flux, even if it’s not intentional,” Margaret Campbell-Brown, a meteor physicist at the University of Western Ontario in Canada, told Space.com. “Although, of course, we disappoint them when their mirror is hit by meteoroids.”
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The JWST team briefly worried that they were underestimating the threat of these small particles in May 2022, when scientists saw a large number of micrometeoroids in the giant golden mirror of space even before conventional scientific observations began.
But by the time the observatory marked the first anniversary of its launch on Christmas 2021, the team’s hopes had returned: Scientists had noticed that the micrometeoroid of concern was so large that they could I expect them to meet something like that more than once a year, and the engineers had decided that the particle was able to hit the most vulnerable area.
“For most of us, we still get about one to two moons per month that we can see,” said Lee Feinberg, director of the optical telescope for JWST at NASA’s Space Flight Center. of Goddard in Maryland, told Space.com about the effects. “At this point, it’s really been very little.”
However, JWST is now looking at a two-decade run, so the team decided to play it safe, to comply with its monitoring policy reducing the time that the telescope will be vulnerable to the strongest impact. “We want those images of the Carina Nebula to look just as good 20 years from now,” Feinberg said.
And that means understanding micrometeoroids.
An unusual place to watch
JWST is in a unique position. The $10 billion observatory sits on what scientists call the Sun Lagrange point 2 (L2), which is 1 million kilometers from Earth on the side facing the sun. L2 is one of the pockets of the planet’s orbit where the gravity is balanced, making it a cheap place to live fuel-wise, and perfect for high-end applications of the infrared optics of the telescope that require protection from day.
But scientists have only sent a handful of spacecraft to L2, and none of them had the JWST disaster: The telescope’s giant mirror is stuck in space, and the engines they constantly monitor its smoothness to help scientists understand their data. Compare that design with a viewing area like The Hubble Telescopecovered by an impact-absorbing tube with no visible scars.
“We’re really able to monitor these things in a way that no one else has been able to do before,” Feinberg said.
Despite the great concern in May, the engineers working on JWST knew all along that micrometeoroids would arrive at the observatory. “If you put anything in space long enough, it’s going to get hit by something,” Bill Cooke, head of NASA’s Meteoroid Environments Office at Marshall Space Flight Center in Alabama, told Space.com. “ISS [the International Space Station], Chandra, Hubble – you mean a vehicle that has been around for years, all shot. Most of the songs are not important in missions, but they are beatable. “
Early in JWST’s design process, mission personnel simulated micrometeoroid impacts on a mirror, though Feinberg noted that engineers did not have the means to accelerate the small particles to the speeds they would reach the solar planets, so the experiments I can’t. really imitate the power of influence. The scientists also used the models they had at the time to understand how many species the observatory might have had during its decades-long lifespan. five.
“That’s kind of the way we approached it in terms of developing JWST,” Feinberg said. “And then, honestly, I don’t know that I thought much about micrometeoroids and our mirrors until we were actually in space.”
But while Feinberg and many of his colleagues were making JWST a reality, meteor scientists were also busy, enhancing their understanding of the space around us.
Scientists have found that only 10 percent of micrometeoroids are associated with the meteors we are most familiar with, which are in the streams that cause certain meteor showers such as Perseids or Leonidas. Another 90% of micrometeoroids are what scientists call sporadics, traveling alone, crossing the solar system in unusual ways, which can make it difficult to understand.
“It’s a lot more work to watch spirals than meteor showers, because they’re not as well organized in events,” Althea Moorhead, meteor scientist at NASA Marshall, told Space.com.
(Feinberg said that the JWST team believes that the effects seen by observers are from sporadics.
Scientists also know what type of body micrometeoroids come from: about 90% from the comets and 10% off asteroids, may be rare active asteroids or debris from collisions between space rocks. And the micrometeoroid’s origin shapes its impact. “It really makes a big difference if your spacecraft gets hit by a solid rock instead of a small grain type,” Campbell-Brown said. “One is like being shot with sand, and the other is like being shot.”
Since micrometeoroids are too small to be seen by any telescope, they are difficult to study, so scientists have combined three main methods.
First, scientists can learn about a nearby meteoroid because of their interaction with Earth’s atmosphere. As each meteoroid travels through space, its sides heat up and drift away, leaving what scientists call an ionization trail, which radar systems can specifically detect.
“The small particles themselves are too small for radar to detect,” Campbell-Brown said of meteoroids. But the trails they leave behind are bigger. “All those electrons in the atmosphere have a cross-sectional area the size of a plane’s carrier, so that’s where we can get a really good signal from these tiny, tiny particles.”
And these pathways provide scientists with an array of data. The Canadian Meteor Orbit Radar, used by Campbell-Brown in Ontario, captures thousands of meteor tracks every day, and that’s enough information to calculate the orbit of each object, he said. “So we get thousands and thousands of meteor orbits every day, which really helps us build a picture of where these little particles are coming from,” Campbell-Brown said.
Second, scientists can look at data from two key activities. NASA won three Pegasus Spaceship in the 1960s and 1970s; each wing sported a large one designed to catch meteoroids and rise to the altitude that the Apollo astronauts would reach. Pegasus was followed in the 1980s by Long Term Exhibition Centerwhich the space shuttle program left for about six years and then returned to Earth, which led scientists to directly study the wounds caused by the meteoroid.
With only four objects that have never left Earth’s orbit, the spacecraft’s data is limited, but still useful. “Most of our data is looking at meteors, but it’s nice to have another way of knowing to help us clear up some of the ambiguities,” Moorhead said.
Help from computers
But that’s actually what scientists have by way of observation, so the last method is modeling.
Scientists can use computers to simulate the smallest pieces of debris in the solar system, how it’s formed and how it moves; they can smash asteroids to smithereens, create artificial comets and watch them smash into space, and test whether JupiterStrong gravitational forces can create meteor trails.
These days, the models are robust enough to include where the parts of the guide come from. “Our models are so advanced that we can tell you which are the most dangerous routes to look at, whereas the old models were very polluted, if you will,” Cooke said. It is very important information for JWST, as the head impacts are very strong and cause a lot of damage.
However, knowing what is happening around JWST is a tricky business, since the two direct observation sources are from the Earth’s environment and there is no guarantee that the two locations are the same when it comes to micrometeoroids.
“The problem we have is that the meteors we see are generally close to the Earth, because you will look at them in the Earth’s atmosphere or you have some impact on the satellites,” Auriane Egal, scientific advisor at the Planetarium Canada’s Rio Tinto Alcan, which works to model meteor streams, told Space.com.
He added: “You can never say, ‘I’m sure at L2 that’s what’s going on.’ validate your theoretical models and your numerical models and use that as a basis for predicting what will happen in other parts of the solar system.”
So far, JWST’s experiences suggest that scientists are on track with their environmental predictions at L2. However, observatories are changing their approach, reducing the amount of time the telescope’s mirror can point forward, when it is most vulnerable to impact – and therefore dangerous. a lot.
No one expects micrometeoroids to take such a high toll when scientists consider the JWST legacy years from now. But it’s probably not the last telescope we’ll send to L2, and it’s not the last telescope with a bare mirror. It’s important to know what’s going on out there.
Email Meghan Bartels at firstname.lastname@example.org or follow her on Twitter @meganbartels. Follow us on Twitter @Spacedotcom and further Facebook.