Low Earth orbit is an increasingly crowded place as the next peak period of solar storms arrives. What’s the forecast for space technological systems?
The Australian Space Operations Centre had its inaugural big alert the weekend before last. The Sun decided to celebrate Halloween with the first powerful flare of the new solar cycle.
According to the Bureau of Meteorology Space Weather Services forecaster Dr Zahra Bouya, it turned out to be a “trick”. “It didn’t eventuate the way we expected it to,” she says.
Space weather suddenly has great significance to Australia.
When the last cycle of solar flares ebbed just 11 years ago, there was no Australian Space Agency (ASA). The Australian space industry was nascent. The global low-Earth-orbit (LEO) CubeSat craze was at the just-about-to-take-off phase. Now, they’re everywhere.
The Halloween Coronal Mass Ejection (CME) was detected on 28 October at 1535 UTC. Space operators were given three days’ warning of the approaching plasma storm.
“We’re coming into a period over the next three years where we’re going to see a lot of risk from space weather events right at a time when we’re becoming more dependent on space-based assets,” says Space Industry Association of Australia (SIAA) CEO James Brown. “There’s a whole lot of trouble ahead, and that touches on many different sectors. So there’s a lot of planning going into that.”
Currently, Australia’s embryonic space industry has only a handful of these relatively cheap and straightforward devices in orbit – scattered among the ever-expanding constellations of them launched by major international enterprises.
Not only is LEO starting to get crowded. It’s about to get bumpy.
“We’re in a solar ascendancy phase, with an increasing number of strong flares and geomagnetic storms,” says Bouya. “And that means problems for all technological systems in space.”
The Halloween Coronal Mass Ejection (CME) was detected on 28 October at 1535 UTC. It was classified X1 (“X” for the most potent class of flare, “1” for its intensity), and space operators were given three days’ warning of the approaching plasma storm.
The issues include radio interference (designated “R” and measured on a scale of 1–5), which takes about eight minutes to arrive at Earth; radiation storm (designated “S”), which can arrive anywhere between 20 minutes and several hours after a flare; and there are geomagnetic storms (designated G) – these can take hours to days to arrive at earth.
The Halloween X1 flare (the strongest ever recorded was 28+) was predicted to produce a G3 category geomagnetic storm.
“Our modelling and experience led us to predict this one would be a strong one,” Bouya says. “We had a dense cloud and a high speed. But it didn’t happen. We don’t know how or why.”
As the charged particles carried less speed, they produced less shock when striking the Earth’s magnetic field. That means the storm was less intense.
The geomagnetic variety of solar storm is what the BoM’s Space Weather Services is most concerned about. It can be a significant problem for ground-based electricity grids and communications cables – essentially anything large and conductive, such as pipelines.
But it’s particularly problematic for satellites.
“This one can impact all systems satellites rely on,” Bouya says. “There’s the GPS networks and all the technological systems they carry. These are interdependent. They need stable power supplies for everything inside. And geomagnetic storms typically last for three days.”
They interact with the Earth’s magnetic field during that time, causing the upper atmosphere to heat up and expand. They also charge the ionosphere, causing interference with high-frequency radar and communications systems.
With the proliferation of CubeSats, that means internet-service-providing constellations can be disrupted. Not to mention the communications relays used by emergency services and defence.
Geomagnetic storms can be a problem for electricity grids and communications cables – but they’re particularly problematic for satellites.
“It can be a matter of life or death for our emergency services if they have no HF communications,” says Bouya.
All LEO CubeSats face the risk of being buffeted by the Earth’s ballooning atmosphere, with drag throwing them off course or pulling them out of orbit. And sensitive onboard systems can be “fried” by an electrical charge.
“We are trying to develop an advanced system of warnings to energy and satellite operators to take preventative measures,” Bouya says. That means as much advanced warning as possible to put delicate computers and sensors into “safe mode”, or possibly even manoeuvre their satellites to a safer altitude or orbit.
That’s not easy.
Seeing the light
The whole point of CubeSats is for them to be small, lightweight and cheap. Which is why many operators are taking a gamble and fitting out CubeSats with an orbital life of just two or three years with minimum amounts of protection.
But exactly how much resilience must be built into their systems – either in the form of shielding or surge protectors – is yet to be seen.
These were the first storms they’ve experienced.
General manager national security and space Stephen Alexander says the BoM’s Space Weather Services is in the process of relocating to Adelaide.
“There’s a whole range of space-based systems and sectors within Australian industry and community now that are vulnerable to space weather events,” he says. “And the space industry itself is just one of them.”
The move to Lot Fourteen is about forging connections.
“We need to see how we can provide the space industry with what it needs – and that’s both terrestrial launch meteorology and space weather forecasting,” he says.
By being among so many start-ups and small-to-medium enterprises, Alexander hopes the bureau can help businesses identify the hurdles space weather may present before it is experienced first-hand.
“We want to be there for those designing satellites, working with defence and the aviation sector, and all the other areas to say, ‘how can we improve our tools and systems to give you the warnings you need at the times you need them?’ so they can design their systems around the reliability of our information.”
The big test is just a few short years away.
“The next solar maximum will be around 2025. We want to be in Adelaide and ready to make sure we can really support the space sector during increased space weather events.”
The BoM has a lot riding on understanding the Sun. Several CubeSat projects now in orbit or on their way to the launchpad are carrying experimental sensors and systems aimed at capturing high-resolution data of Australia’s terrestrial weather – such as soil moisture contents, fire warning and so forth.
Australia’s CUAVA-1 testbed CubeSat will be monitoring plasma activity in LEO. Others will be watching how the ionosphere shifts and mutates. But, Bouya says, space weather comes from the Sun.
The Sun’s climate is well understood. History shows the 11-year boom-bust solar storm cycle is well entrenched. But when it comes to the short-term nature of solar weather, the complex interplay of magnetic fields and boiling plasma are only just beginning to be untangled.
Bouya says several big international satellites are currently watching it, including NASA’s Solar and Heliospheric Observatory (SOHO) and the Parker Solar Probe. These are contributing to a “big data” effort to better understand its moods. “We’re trying to correlate everything with our algorithms to get our warnings reliable and out as early as possible,” she says.
We know what’s happened in the past, so formulating probabilities of solar storms at any particular point over the next three years isn’t a problem. Identifying one as it emerges, however, is. And that’s why current alerts can offer as little as an hour’s warning.
“Based on all the information we have on any particular region of the Sun, we can model a probability of a shock,” Bouya says. “We can say ‘this region has a 20 per cent chance of exploding tomorrow’. But we won’t know until it does.”
Jamie Seidel is a freelance journalist based in Adelaide.