<p>If a solar flare occurred during a lunar mission (bearing in mind that in routine one-week lunar missions the astronauts are protected from solar radiation by Earth's magnetotail) would the magnetotail be enough to protect them from the high-energy protons (the most dangerous output of solar flares) during a moonwalk during full moon, to the point the moonwalk is safe for their health?</p>
<p><a href="https://i.sstatic.net/KnRZb.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/KnRZb.png" alt="https://www.nature.com/articles/s41567-021-01203-5" /></a></p>
<blockquote>
<p>The moon spends about six days each month inside Earth's magnetic tail, or &quot;magnetotail.&quot; The Moon and the Magnetotail (<a href="https://www.nasa.gov/topics/moonmars/features/magnetotail_080416.html" rel="nofollow noreferrer">https://www.nasa.gov/topics/moonmars/features/magnetotail_080416.html</a>)</p>
</blockquote>
<blockquote>
<p>The lunar nearside spends ~27% of its daytime in Earth’s magnetotail where the solar wind flux is reduced by as much as ~99% Formation of lunar surface water associated with high-energy electrons in Earth’s magnetotail - Nature Astronomy (<a href="https://www.nature.com/articles/s41550-023-02081-y" rel="nofollow noreferrer">https://www.nature.com/articles/s41550-023-02081-y</a>)</p>
</blockquote>
<blockquote>
<p>The most dangerous emissions from flares are energetic charged particles (primarily high-energy protons) and electromagnetic radiation (primarily x-rays).https://hesperia.gsfc.nasa.gov/sftheory/spaceweather.htm</p>
</blockquote>
<p>image source <a href="https://www.nature.com/articles/s41550-023-02081-y" rel="nofollow noreferrer">https://www.nature.com/articles/s41550-023-02081-y</a></p>

CC BY-SA 4.0
2023-12-12T20:05:33.763Z
Not sure about the answer here but I'm just going to point out that a geomagnetic storm (such as from a CME) can significantly compress the magnetosphere and alter the geometry of the tail.
Darth Pseudonym
CC BY-SA 4.0
2024-08-05T12:54:21.477Z
@darth the solar flare precedes any CME by a large margin and not all solar flares lead to CMEs anyways
Harrychink
CC BY-SA 4.0
2024-08-05T14:07:34.947Z
@Harrychink The question is asking about "high energy protons", so we're clearly talking about the whole flare/particle event/CME ecosystem rather than solar flares as a distinct phenomenon.
Darth Pseudonym
CC BY-SA 4.0
2024-08-06T01:48:32.813Z
@darth a lot of CMEs fall back into the sun anyways and besides, astronauts would have some time to protect themselves before the come actually hit
Harrychink
<solar-flare>
Would the magnetotail protect astronauts caught outside during a solar flare enough for their safety?
Mark Besser
# Would the magnetotail protect astronauts caught outside during a solar flare enough for their safety?

(Asked by: username_0 on 2023-12-12)

If a solar flare occurred during a lunar mission (bearing in mind that in routine one-week lunar missions the astronauts are protected from solar radiation by Earth's magnetotail) would the magnetotail be enough to protect them from the high-energy protons (the most dangerous output of solar flares) during a moonwalk during full moon, to the point the moonwalk is safe for their health?

[![https://www.nature.com/articles/s41567-021-01203-5](https://i.sstatic.net/KnRZb.png)](https://i.sstatic.net/KnRZb.png)

> The moon spends about six days each month inside Earth's magnetic tail, or "magnetotail." The Moon and the Magnetotail (<https://www.nasa.gov/topics/moonmars/features/magnetotail_080416.html>)

> The lunar nearside spends ~27% of its daytime in Earth’s magnetotail where the solar wind flux is reduced by as much as ~99% Formation of lunar surface water associated with high-energy electrons in Earth’s magnetotail - Nature Astronomy (<https://www.nature.com/articles/s41550-023-02081-y>)

> The most dangerous emissions from flares are energetic charged particles (primarily high-energy protons) and electromagnetic radiation (primarily x-rays).https://hesperia.gsfc.nasa.gov/sftheory/spaceweather.htm

image source <https://www.nature.com/articles/s41550-023-02081-y>

**Tags:** solar-flare

> **Comments:**
> **username_1**: Not sure about the answer here but I'm just going to point out that a geomagnetic storm (such as from a CME) can significantly compress the magnetosphere and alter the geometry of the tail.  
> **username_2**: @darth the solar flare precedes any CME by a large margin and not all solar flares lead to CMEs anyways  
> **username_1**: @username_2 The question is asking about "high energy protons", so we're clearly talking about the whole flare/particle event/CME ecosystem rather than solar flares as a distinct phenomenon.  
> **username_2**: @darth a lot of CMEs fall back into the sun anyways and besides, astronauts would have some time to protect themselves before the come actually hit  

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## 0 answers

