Space Weather

When we talk about weather, we think of it as something that only takes place on Earth, or at least on the surface of a planet.

But weather that happens out in the vacuum of space is a real phenomenon, albeit different from how we understand weather on Earth, and one of which spacecraft operators should be aware.

Space weather, alongside debris and the possibility of collisions, is one of the risks that satellites face once they’re in orbit. The circumstances and effects of space weather are complex, more so than falling rain or thunderstorms.

What is space weather?

Space weather encapsulates the activity that occurs between the Sun and Earth, typically originating from the former and impacting our technology on (or above) the surface of the latter. The science and study of space weather is known as heliophysics.

Space weather doesn’t just affect Earth; it can influence the solar system beyond. This weather is the result of activity on the surface of the Sun, which can include:

Coronal holes

These are areas of temporary cooldown in the Sun’s corona, the plasmatic outermost layer of its atmosphere. Coronal holes cause the Sun’s magnetic field – which is usually ‘closed’ – to extend out into space and allow solar winds to escape in a faster-than-normal stream.

Coronal holes’ effects can last for months, but they are typically quite minor in terms of effects on Earth. However, they can sometimes slip through Earth’s own magnetic field and disrupt certain electrical equipment and communications.

Solar flares

Solar flares are eruptions that occur when charged particles in the Sun’s atmosphere are intensely charged with magnetic energy. This sudden release of stored energy creates huge bursts of radiation that span the electromagnetic spectrum.

Solar flares are split into three categories by scientists:

  • C-class flares – relatively small and minor with few effects on Earth.
  • M-class flares – medium in size, can cause some blackouts to radio communication particularly to the polar regions.
  • X-class flares – the most major type, X-class events can cause global radio blackouts and long-lasting radiation storms.

Solar flares affect the ionosphere, where the very limits of Earth’s atmosphere meet space. The ionosphere plays a role in radio and GPS communications, meaning disruptions caused by space weather can have knock-on effects on everyday life.

Solar wind

Solar wind is a constant stream of protons and electrons that ‘blows’ from the Sun’s corona. Solar wind particles can travel as fast as 500mph through space.

Solar winds colliding with Earth’s magnetosphere are what causes aurora displays, commonly known as the Northern Lights.

The Sun’s solar winds extend out incredibly far throughout the solar system, covering hundreds of millions of miles of space in an area known as the heliosphere, which serves to protect life on Earth from cosmic rays.

What effect does solar weather have on satellites?

Space weather can affect satellite electronics, or it can impact the lifespan of the satellite itself and affect the time the satellite is able to stay in orbit.

Surrounding Earth are two zones known as the Van Allen radiation belts, which trap energetic particles from the solar wind. Most orbiting satellites are partly or wholly within these zones, subjecting them to the risk of damage to sensitive onboard electronics like sensors and solar cells.

Geomagnetic storms, excited by solar eruptions colliding with Earth, can also disrupt radio communications by interfering with signals and their ability to travel between ground stations and satellites.

Charged particles can accumulate on satellites and eventually discharge, overwhelming the resistances built into the satellite and delivering sudden shocks that overwhelm circuitry and components.

Fortunately, there are certain patterns to solar weather can be observed and predicted, and the solar cycle plays a part in this.

How long does a solar cycle last?

A solar cycle lasts approximately 11 years. The end of one cycle and the start of the next is marked by the Sun’s magnetic field flipping over, switching the positions of its north and south poles.

The amount of activity taking place on the Sun’s surface changes with each cycle. Activity like solar flares increases as a solar cycle progresses, though not every cycle ends up being the same during its solar maximum (the middle of the cycle when the Sun has the most sunspots). Some cycles might see turbulent space weather whereas others may not.

What does the near future of solar weather look like?

Solar weather presents an ongoing challenge to satellite operators, particularly those operating small satellites and/or satellites in low Earth orbit.

SpaceX recently suffered the loss of 40 brand-new satellites intended to add onto its growing Starlink network. A geomagnetic storm struck just one day after the satellites’ launch, which increased the size of the Earth’s atmosphere enough to significantly increase the drag acting upon the satellites.

SpaceX is just one example of loss in this regard, as the onset of a recent new solar cycle has been producing similar problems for other operators. Experts say this could be the start of a difficult time for satellites, with some sinking as much as 12 miles per year over the usual 1-2 miles.

Satellites in LEO always face some drag, but the near future of space weather could present a magnification of this problem that is particularly tricky for New Space investors using nanosatellites like CubeSats to achieve their missions.

However, such investors might find some comfort in the idea that one thing they can control for certain is the competence of their satellite’s onboard software.

Reliable flight software, whatever the weather

Bright Ascension answers the need for COTS satellite software that is fast to integrate, easy to use, and affordable. Our Flight Software Development Kit and Mission Control Software solutions are perfect for small satellite missions, reducing time to market and keeping builds within budget.

Book a demonstration or request a free trial by getting in touch today.