Deadly sun

Solar storms in today’s spaceships are a gross risk for manned spaceflight

Again and again, massive flares erupt from the sun and a particle storm races through the solar system. The Earth and its inhabitants are protected from the electrically charged particles of the solar wind by the magnetic field of our planet. Astronauts in space, however, have to cope with this additional burden besides cosmic radiation. New calculations now show that a massive solar storm like the one of 1859 poses a deadly risk to space travelers.

Our central star repeatedly shows spots on its surface that are caused by magnetic field fluctuations and are cooler, which makes them appear darker. From these spots rise again and again huge "flares", coarse flares of ionized gas, which are hurled into space. Particle streams hurtle toward Earth at speeds of up to 800 kilometers per second. We are currently living in a period of particularly strong solar activity (the sun has turned on the afterburner), but a particularly intense geomagnetic storm caused by solar turbulence took place almost 150 years ago.

Deathly sun

Solar storms are also a risk for astronauts on the International Space Station (ISS)

In September 1859, British astronomer Richard Carrington observed a solar storm (Carrington’s Solar Flare) that went down in history as a solar superstorm. This solar flare ignited auroras over southern Italy, Cuba or Hawaii. The telegraph cables in both Europe and North America were briefly closed (Unusually strong solar flare observed). Bruce Tsurutani of NASA’s Jet Propulsion Laboratory explains how this happened back then:

What happened in 1859 was a combination of different events on the sun that all happened at the same time. Each event by itself would not have been particularly noteworthy. But together they produced the most powerful eruption the Earth’s ionosphere has had to endure in recorded history. What resulted was a perfect solar storm. With the solar flare a massive cloud of magnetically charged plasma was explosively released. These particles were released in a beam-like manner, so that not all of them were heading towards Earth. Usually it had taken three to four days for the Earth to be affected, but in this case it only took 17 hours and 40 minutes.

When high-energy particles hit the Earth’s atmosphere today, satellites fail, computers are disrupted, and power supplies collapse (solar storms can crash PCs). The astronauts on the International Space Station must then take cover in particularly protected areas (pathogenic solar flares).

Space weather and astronauts

Above the Earth, astronauts are exposed to considerable cosmic radiation, which can affect their health. This is a fundamental problem for space travel, as it exposes astronauts to an increased risk of cancer. Solar winds can greatly increase this risk and, as the science magazine New Scientist recently reported, an event like the one in 1859 could even kill insufficiently protected space travelers – for example on the moon or on a mission to Mars – instantly.

Lawrence Townsend of the University of Tennessee and colleagues have studied the tracks of solar storms over the past 500 years. They analyzed the isotopic distribution of beryllium in Gronland ice, which has been studied from cores as far back as 1424. Beryllium-10 is formed when cosmic rays enter the Earth’s atmosphere and it was deposited in the perennial ice of the poles.

Townsend’s team concluded that the solar storm nearly 150 years ago was the most intense event of its kind in the epoch. The scientists extrapolated what dose of radiation astronauts were exposed to by such a flare. If the astronauts were traveling in a ship or were on a lunar station with only a few centimeters of aluminum skin separating them from space, they would certainly get radiation sickness and possibly even die.

Astronauts on the International Space Station are less affected by the problem because it is still partially within the protective shield of the Earth’s magnetic field, and because of the close monitoring of the sun’s surface there is always enough time for a warning to be given so that the crew can move to specially protected areas. Consequences arise above all for the planning of longer journeys through space, z.B. for a future Mars mission, with which all space agencies are currently toying (Moscow has the Red Planet firmly in its sights). This is especially true for the design of the spaceships. Lawrence Townsend explains:

Aluminum does not provide good shielding from radiation. We are looking for alternative materials, such as polyethylenes or carbon foams impregnated with hydrogen. A worst-case scenario would likely be survivable if materials other than aluminum were used.

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