NASA seemed ready on Wednesday to loft its latest robotic mission to Mars, ESCAPADE, into space aboard a rocket from the company Blue Origin.
But the launch was scrubbed on account of “highly elevated solar activity and its potential effects” on the spacecraft, the company said in a post on social media.
On Tuesday, two blasts of solar material, made by a pair of powerful coronal mass ejections — giant explosions from the sun’s surface that spew streams of charged particles — crashed into the Earth’s magnetic bubble in space. They caused gorgeous light shows in night skies that may again be visible on Wednesday night into Thursday morning. But these solar storms and continuing activity also necessitated careful monitoring of the fleets of satellites in orbit, and of those that are headed there.
“History points to these compound C.M.E.s and overlapping storms as being the most significant for space weather effects,” said Daniel Baker, a scientist at the University of Colorado Boulder’s Laboratory for Atmospheric and Space Physics. “That’s what we’re in the throes of right now.”
Activity from the sun, which ebbs and flows on an 11-year cycle, reached a peak last year. According to Dr. Baker, the phase after a peak is often when flares, explosions and other solar activity become most prevalent. When directed toward Earth, this activity can cause disturbances — a geomagnetic storm — in the planet’s magnetosphere, the protective bubble that shields us from harmful solar radiation.
Three coronal mass ejections fired off the sun on Sunday, Monday and Tuesday. Two of those compounded and hit Earth’s atmosphere on Tuesday, creating a risk of radio blackouts, power grid disruptions and aircraft reroutes.
Scores of satellites circling the Earth were also threatened. But the amount of risk a satellite experiences during a geomagnetic storm depends on the altitude of the satellite’s orbit, according to Kerri Cahoy, an engineer at the Massachusetts Institute of Technology.
Satellites in low-Earth orbit can experience anomalies, like signal dropouts and reboots. But molecules in Earth’s atmosphere and the strength of its magnetic field can offer some natural protection for satellites closest to the ground, Dr. Cahoy said.
At higher altitudes, where Earth’s magnetic field is weaker (and where GPS and many weather satellites live), spacecraft experience much higher doses of radiation during geomagnetic storms. While those storms are happening, Earth’s magnetosphere can get peeled back, leaving satellites more exposed to the effects of space weather.
“But they’re built for it,” Dr. Cahoy said, because spacecraft orbiting that high are usually designed with special shielding that makes them more tolerant of solar radiation. “Nobody sends a satellite up there without it,” she added.
In the past, most satellites were “radiation-hardened,” Dr. Baker said. But today, he said, many commercial satellites in low-Earth orbit are not, making them more susceptible to loss of function or communication disruptions.
Coronal mass ejections also make the air warmer and cause Earth’s atmosphere to temporarily puff out, potentially introducing drag to parts of low-Earth orbit. Last year, a geomagnetic storm caused some NASA satellites to drop by more than a thousand feet. In 2022, a solar outburst resulted in 40 newly launched SpaceX satellites getting knocked out of commission.
Many satellites are designed to operate at a specific height above the ground, so drops in altitude can hinder operations. Altered satellite trajectories to counter drag can also increase the chances of spacecraft collisions, either with one of the thousands of satellites currently in orbit or the millions of bits of space debris floating around.
When it came to the decision not to launch NASA’s ESCAPADE mission, Rob Lillis, the mission’s principal investigator, said they would have launched had the solar activity ended on Tuesday. But on Wednesday morning, they received a forecast that another coronal mass ejection would arrive just as the mission’s two orbiters were to be deployed in space.
At that time, “some really critical things have to happen,” Dr. Lillis said. The radiation could have crashed the sp like the deployment of the solar arrays, which are needed to keep the mission running. “We didn’t want to risk doing that in an environment that was even more dangerous,” he said.
Dr. Baker said the possibility of collision is another reason it makes sense to scrub a rocket launch.
During geomagnetic storms, NASA and other agencies that track satellites and space debris lose timely information that has to be reacquired before it is safe for any spacecraft to take off, Dr. Baker said.
“The chances of a collision with a launch go up quite considerably,” he said. “And the last thing you want to do is run into something.”
The scheduled launch on Thursday of a satellite operated by Viasat, a global communications company, is still on — for now. But in a statement United Launch Alliance, the flight rocket’s operator, said that it was “closely monitoring solar activity” and that launch weather officers “plan to re-evaluate the solar weather conditions prior to the start of our countdown.”
In a post on X on Wednesday afternoon, the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center said that the impending coronal mass ejection, even stronger and faster than the previous two, had arrived.
Effects of that event are expected to begin on Wednesday and last through Thursday. According to the British Geological Survey, the activity could cause “potentially the largest solar storm to hit our planet in over two decades.”
Dr. Baker likened the impacts seen so far to the series of Halloween storms that pummeled Earth’s magnetosphere in 2003. But back then, there were only a few hundred satellites in low-Earth orbit, he said, and now there are several thousands.
Agencies that monitor space weather these days, however, are more prepared. “We don’t know for sure what the sun may throw at us,” Dr. Baker said. “But we hope that we, as a space weather community, are getting better at helping to avoid the most severe consequences.”
Kenneth Chang contributed reporting.
Katrina Miller is a science reporter for The Times based in Chicago. She earned a Ph.D. in physics from the University of Chicago.
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