In this live stream, we have an astronaut facing the sun (we've seen his hands actually):

enter image description here

I thought people doing an EVA should avoid the sun at all cost, but here he's facing it.

From what kind of deadly things/events does his suit protects him against?

(a rough guess is radiations but a detailed explanation would be appreciated)

  • $\begingroup$ How about editing your question - including the title - to clarify what you really want. If your question is "What protection does the suit provide" your title is totally inappropriate. $\endgroup$ Jun 17, 2017 at 1:51

3 Answers 3

  1. Facing the Sun does not mean looking at it. As there are no air there, you have more light looking directly at the Sun, but LESS light looking somewhat in its direction, but not straightly. Because of that, BTW, you can see stars simultaneously.

  2. Even while looking at the Sun directly, you still could do it for the short time enough for taking a photo, without any real harm.

The spacesuit protects the wearer from cold, heat, extra visible light, UV, soft roentgen, alpha and beta-rays and protons. A bit from gamma-rays. Earth magnetic field is blocking most of Sun alpha, beta rays and protons and also charged energetic cosmic rays. But not from neutrons and gamma-rays. And the spacesuit and even the spacecraft do not protect from them also. So, the space travels remain very dangerous. Space radiation is 50-fold more effective than typical radiation on Earth at causing a type of liver cancer called hepatocellular carcinoma in mice.

Wiki has much info on the space suits history.

The best fiction literature where space suits are impotant is Have Space Suit—Will Travel of Heinlein.

  • $\begingroup$ "Because of that, BTW, you can see stars simultaneously." Do you have a citation for that claim? (Assuming, of course, that you mean stars besides the Sun, but I'm pretty sure that's a reasonable assumption to make here.) $\endgroup$
    – user
    Jun 16, 2017 at 9:30
  • $\begingroup$ curious.astro.cornell.edu/about-us/81-the-universe/… Really, the physics arguments are based not on references, but on thinking based on physical laws. $\endgroup$
    – Gangnus
    Jun 16, 2017 at 13:21
  • $\begingroup$ There is not much protection by the suits against roentgen or xrays, only against very long waves. $\endgroup$
    – Uwe
    Jun 17, 2017 at 20:26
  • $\begingroup$ @Uwe Roentgen=xrays. Photons, created by electrons. They start at 2nm wavelength. These soft kind can be significantly weaken by any metal film. On the other hand, waves can be practically very short and still be xrays. en.wikipedia.org/wiki/X-ray. These of course, remain dangerous. $\endgroup$
    – Gangnus
    Jun 17, 2017 at 21:18
  • $\begingroup$ @Gangnus I did know before Roentgen=xrays $\endgroup$
    – Uwe
    Jun 17, 2017 at 21:37

There is no real reason why astronauts should avoid the sun while spacewalking. While it is true that things like seeing what you are doing, dealing with radiation and heat management are somewhat more difficult the suits are designed for this. Remember that ISS revolves around the earth once every 90 minutes (give or take) and spacewalks can take up to 8 hours. It would be exceedingly difficult to perform a spacewalk where they would have to 'run for cover' every 45 minutes.

The answer on How are EVA's in LEO affected by being at the night side of Earth? has some very good details on how day versus night affects spacewalks.


The shuttle/ISS Extravehicular Mobility Unit (EMU) aka spacesuit incorporates a gold-film plated sun visor to protect the astronaut's vision when looking in the general direction of the sun. It is called the Extravehicular Visor Assembly.

enter image description here

from here

In this picture you can see the visor totally raised (gold rim at top of bubble) enter image description here and in this picture you can see the visor half raised. enter image description here

  • $\begingroup$ Why don't they use so called "virtual reality" whre their eyes are safely projected with visualised data from external sensors? (Barring some spelling errors in the code, of course :-) $\endgroup$
    – LocalFluff
    Jun 17, 2017 at 6:32
  • 2
    $\begingroup$ Because VR is far more failure-prone than your eyes. $\endgroup$
    – Hobbes
    Jun 17, 2017 at 7:07
  • $\begingroup$ Also because VR capable of matching the resolution and sensitivity of the human eye isn't really available $\endgroup$
    – ikrase
    Aug 24, 2020 at 20:03

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