"It appears that the new Cycle 25, peaking around mid-decade, will be more active than the previous cycles."
Operators of smallsats are facing challenges keeping their spacecraft in orbit and functioning because of a new solar activity cycle that may be stronger than forecasts.
Space weather experts warned that the relatively benign conditions of recent years are coming to an end during a panel discussion at the 36th Small Satellite Conference on Aug. 8.
“Whatever you’ve experienced in the past two years doesn’t matter,” said Tzu-Wei Fang, a space scientist at NOAA’s Space Weather Prediction Center (SWPC). “Whatever you learned the past two years is not going to apply in the next five years.”
The higher density of the upper atmosphere is one result of increased space weather activity, causing more drag on satellites. When a solar storm struck on February, 38 of 49 newly launched SpaceX Starlink satellites were forced to reenter because their thrusters couldn’t cope with the enhanced atmospheric drag.
“That storm was actually a minor storm in our catalog. It’s not a huge storm,” Fang said.
As part of its study of that incident, SWPC partnered with SpaceX to better predict atmospheric conditions and the risks they pose to satellites using space weather models.
As part of its evaluation of models, SpaceX also provides orbit data from its Starlink satellites. “We’re trying to see how we can utilize this data to improve the density estimations.”
Space traffic management is also affected by increased atmospheric drag.
After one storm, everything goes everywhere in two days, experts said, since drag effects vary among satellites and debris, and that’s when collisions should be considered.
There was a relatively mild 11-year solar cycle before this upsurge in activity, called Cycle 24, that coincided with the launch of an increasing number of satellites. As a result, many satellite operators aren’t familiar with the impacts of an active sun.
It appears that the new Cycle 25, peaking around mid-decade, will be more active than the previous cycles.
“If you look at the beginning of this year, things are very crazy. We’ve had a solar flare almost every week,” she said.
Solar storms are expected to become more powerful over the next few years as the current cycle trends are higher than predictions.
Having reached this point, we’ve already exceeded our predictions.
Satellite operations can also be disrupted or even damaged by solar storms.
Smallsats, in particular, may be affected in this way, as their electronics are often commercial-off-the-shelf COTS, which are more susceptible to solar activity than radiation-hardened components.
According to industry officials attending the conference, concerns about increased solar activity have not yet led to a significant shift from COTS to rad-hardened electronics for smallsats.
As per satellite operators’ recommendations, rad-hardened components can be used on critical subsystems while retaining COTS components on less critical subsystems.
Solar storms cannot be ignored by satellite operators, according to Fang.
“It’s very important that we all be aware of the impact of the space environment, how your satellite is going to mitigate this radiation environment and how you’re going to mitigate the drag effects.”
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