Divert power to shields – the solar maximum is coming

By Brett Carter, RMIT University

Over the past few months our planet has been impacted by an increasing number of solar explosions that have erupted from the sun’s surface.

Even though next year’s predicted solar maximum – the period of greatest activity in the sun’s 11-year cycle – is expected to be smaller than its predecessor a decade ago, the impact on society over the coming months could be worse than in the past.

The main reason for this is that there has been an increase in society’s dependence on space-based services that are severely influenced by these disturbances.

The effect that space weather has on our everyday lives resides in our reliance on technology, in particular electricity grids, radio communications and satellite-based services.

While our reliance on electric power is obvious, our reliance on radio communications may not be.

Difficult positions

By “radio communications” I don’t just mean walkie-talkies and two-way radios. Military organisations around the world, including Australia’s defence forces, heavily utilise ground-based radar surveillance for routine border protection, and have done so since the end of the second world war.

An additional aspect of our current technology that is strongly influenced by space weather events is satellite communications. This not only includes both satellite phones and TV broadcasting, but also satellite positioning services, such as the Global Positioning System (GPS).

The direct effects of space weather events on our satellite communications are twofold:

1) Satellites are subjected to high radiation doses from the space environment that can cause hardware faults and failures.

2) Satellite-transmitted radio signals are manipulated by the layer of partially ionised gas in Earth’s upper atmosphere – the ionosphere.

One example in which satellites succumbed to the sun’s wrath was the loss of two Canadian telecommunications satellites that were subjected to an intense geomagnetic disturbance in 1994. The satellites were replaced at a cost of about US$400 million.

Earth’s ionosphere is a dominant source of error in GPS positioning due to its effects on radio signals passing through the atmosphere. The commercial “SATNAVs”, and more recently smartphones, that people commonly use for navigation across town are accurate to within a few tens of metres, and therefore a drop in accuracy using these devices during geomagnetic storms may not be obvious.

But industries that conduct high-precision (centimetre-level) positioning operations, such as surveying and exploration mining, are strongly impacted by space weather disturbances.

Drag and drop

A less direct space weather effect on our technological infrastructure is the dramatically increased level of atmospheric drag experienced by low-Earth orbiting satellites as the upper atmosphere swells due to the increased heating during geomagnetic storms.

Artist’s interpretation of a GPS satellite.

Low-Earth orbit satellites reside (generally speaking) at altitudes lower than 2,000km and a large portion of those are Earth Observation Satellites (or EOS for short).

Many Australians would be unaware of how much our government departments and organisations rely on EOS in their day-to-day operations. The Federal Government spends about A$100 million per year on EOS data acquisition.

The services provided with this data contribute A$3.3 billion towards the annual Australian gross domestic product (GDP). This means the government gets more than a 30-fold return on its EOS data investment, despite not owning any EOS currently in orbit.

So even though Australia owns very few orbiting satellites, its economy is actually rather heavily reliant on space-based services.

An example of the adverse impact that satellite data gaps have on Australia is the LANDSAT EOS data loss due to retiring and malfunctioning satellites.

This costs Australia an estimated A$100 million in the first year – the federal government’s entire yearly investment – with flow-on effects expected in subsequent years until replacements are launched.

Lost in space

Readers may remember back to 1989 when a large geomagnetic storm destroyed power transformers in Canada, and caused widespread blackouts and circuit trips across Northern America.

But one problem caused by this geomagnetic storm that was far less publicised at the time was that around 1,500 orbiting objects were completely lost by the North American Aerospace Defense Command (NORAD).

Composing the vast majority of these lost objects were space debris or “space junk”.

The rest were operational satellites worth millions of dollars. One of the lost objects was later found to be orbiting at an altitude 30km lower than it was prior to the storm. It took NORAD more than seven days to find all of the objects again and to resume normal operations.

Maintaining focus

From the LANDSAT example above, it is easy to see how vulnerable the Australian economy is to the loss of EOS, due to collisions with space debris, in particular during the days following a large geomagnetic disturbance.

Space weather prediction is a challenging task that a number of organisations around the world specialise in. Those organisations include, but are not limited to, the NOAA Space Weather Prediction Center in the USA, the Solar Influences Data Analysis Center in Belgium and the Australian Space Forecast Centre – the space weather branch within the Bureau of Meteorology.

The importance of the work these organisations do is significantly increasing as we become more heavily reliant on technology into the future.

It is therefore important that space scientists and space weather forecasters internationally remain focused on studying these impacts in the context of providing accurate forecasts for individuals and industries that rely on these technologies.

The next solar maximum will be a testing time.

The Conversation

This article was originally published on The Conversation.
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