The Deadly Threat That Lurks Beyond the Earth
Last time we ventured into deep space we got lucky. Next time we may not.
The night of August 4, 1972, was marked by strange events. In England bright lights appeared in the sky, strong enough to cast shadows in the streets. Power grids all over America recorded strange fluctuations, threatening to cause a large-scale blackout. Along the Vietnamese coast thousands of sea mines, deployed in the war, suddenly erupted in terrifying explosions.
Around the planet scientific instruments recorded equally bizarre things. Observers in Guam spotted a wave of magnetic energy racing across the planet at tremendous speeds —travelling more than three thousand kilometres every second. Satellites failed; their power systems unable to cope with surging currents. A neutron counter in the Vela monitoring system overflowed, triggering fears of a nuclear explosion.
The cause, fortunately, was not an atom bomb. The magnetic storm that swept the Earth in 1972 came from the Sun, a massive outburst of stellar material directed right at our planet. The disturbances it created wrecked havoc on our wired-up world, threatening the grids and technology we rely on.
Luckily, thanks to a fortunate alignment of the Earth’s magnetic shield, the consequences were minor. Had the storm hit a few months earlier, however, when the crew of Apollo 16 were making their way to Moon, the situation might have been much worse.
The type of magnetic storm that hit in 1972 is intensely radioactive. Carried along with the storm are clouds of radiation and energetic sub-atomic particles. On Earth we are protected from most of this — the aurora seen in the night sky show the magnetosphere at work, deflecting them away. But out in space, halfway to the Moon, there is no such protection.
The astronauts aboard Apollo 16 would have had to rely on the thin walls of their spacecraft to protect them. That would not have been enough — analysis shows they would have suffered severe radiation sickness. Had they been on the surface of the Moon — with little available protection — they might have been killed.
Fortunately no big magnetic storm did hit during the Apollo missions. That is partially down to luck, but also due to the nature of the missions themselves. The trips were short, no more than two weeks in length. Astronauts did not venture far from Earth— outside its protective magnetic shield, sure, but not so far they couldn’t have returned to Earth in a hurry had something gone wrong.
That, though, may not have been much help to the astronauts. The storm travelled at enormous speeds, crossing the distance from the Sun to the Earth in less than a day. Even with the advanced monitoring systems we have around our star today, we could not have given them much warning.
For missions further afield — to Mars, for example — the danger is even greater. Voyages will last for months, perhaps years. The astronauts will be far from home, too far for urgent medical help. Out in the vastness of space they will be almost defenceless against the Sun’s wrath.
Fortunately storms as powerful as the one in 1972 are rare. What’s more, they seem to be predictable, at least to some degree. The Sun follows an eleven-year cycle of activity, rising and falling in strength. Right now, in 2021, we are roughly a year into the cycle, meaning the Sun is quiet, but getting more active. By 2024, the year NASA plans to return to the Moon, activity will be close to a peak.
Not all cycles are of the same strength. Some, like the last one, are relatively weak, with few storms heading towards the Earth. Others are strong, hurling large amounts of solar material into space. But how strong a cycle will be is hard to predict in advance, as astronomers still don’t fully understand the processes that drive the Sun’s behaviour.
Until recently it was not clear whether big storms, like the one in 1972, are related at all to the Sun’s activity. Many astronomers thought these were more or less random events, huge outbursts driven by some still mysterious happenings inside the Sun. But a new analysis, published in Solar Physics, seems to have found a pattern.
Big storms, they say, are more likely when the Sun is particularly active — and even more so in a strong cycle. In a sense this is good news. It means mission planners can schedule long spaceflights for periods when the Sun is likely to be quieter. That should protect astronauts from the worst of the Sun’s rage.
But it also raises concerns for the missions planned over the next few years. If NASA is serious about returning to the Moon, or Elon Musk about going to Mars, they will need to take the risk of an angry Sun seriously. Spacecraft can be designed to protect astronauts — the ISS has protected areas for them to take shelter in — but doing so is expensive.
NASA and SpaceX have a choice, then. Delay their ambitions, or spend more money to protect their astronauts. They ignore the wrath of the Sun at their peril.
Following the success of the last Starship flight, Elon Musk and SpaceX have announced even more ambitious plans. According to documents filed with the FCC, SpaceX will attempt an orbital flight of Starship. After circling the planet for just over an hour, Starship will try to land in the ocean, a few miles north of Hawaii.
No date has yet been confirmed for the flight, though the filing is valid until March 2022, giving SpaceX a few months to prepare. Notably the documents suggest the flight will only just reach space — the maximum altitude given is just 72 miles, barely above the official boundary of Earth’s atmosphere.
Nevertheless, the flight will be a remarkable achievement. Starship promises to be one of the most powerful space vehicles ever built, competitive with the mighty Saturn V that once carried astronauts to the Moon. SpaceX may not succeed with their first orbital launch of Starship, but that they are trying at all is a powerful statement of intent.
The James Webb Space Telescope is undergoing its final tests before launch. In the next few weeks the massive telescope will be packed up and shipped to French Guiana, where it will be launched at the end of October. The powerful observatory promises to cast a new eye on the universe, revealing everything from alien worlds to the origins of the stars and galaxies themselves.
So much reporting around health, science and space exploration is unrealistic, hyperbolic and misleading. These are complicated topics and there are often no easy or straightforward answers. Instead what is needed is analysis, discussion and an exploration of the possible ways forward.
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