Space Radiation - Revision history

Lwcamp: /* Jupiter */

2026-04-09T01:00:03Z

Jupiter

← Older revision		Revision as of 18:00, 8 April 2026
Line 136:		Line 136:
	[[File:Jupiter_radiation_environment.png\|thumb\|Radiation dose rate with distance from Jupiter's center, as measured in Jupiter radii<ref name="Podzolko2013">Podzolko, M.V.; Getselev, I.V. (March 8, 2013). [https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=32688.0;attach=541277 "Radiation Conditions of a Mission to Jupiterʼs Moon Ganymede"]. International Colloquium and Workshop "Ganymede Lander: Scientific Goals and Experiments. IKI, Moscow, Russia: Moscow State University.</ref>.]]		[[File:Jupiter_radiation_environment.png\|thumb\|Radiation dose rate with distance from Jupiter's center, as measured in Jupiter radii<ref name="Podzolko2013">Podzolko, M.V.; Getselev, I.V. (March 8, 2013). [https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=32688.0;attach=541277 "Radiation Conditions of a Mission to Jupiterʼs Moon Ganymede"]. International Colloquium and Workshop "Ganymede Lander: Scientific Goals and Experiments. IKI, Moscow, Russia: Moscow State University.</ref>.]]
	Jupiter has one of the largest and strongest magnetic fields of any planet in the solar system. Like that of Earth, it will trap particles from the solar wind and the decay products of cosmic neutrons. However, what really sets Jupiter's radiation belts apart is what happens because of its moon, Io. Io is extremely volcanic, and regularly erupts fountains of sulfur dioxide into space. This gas is then ionized by ultraviolet sunlight, producing positively charged sulfur and oxygen ions. These ions spread out to form the <i>Io plasma torus</i>. Electric currents within the torus, driven by Jupiter's rotation, accelerates ions and electrons to high speeds and can produce dangerous radiation. Jupiter's radiation belts are not as well understood as those of Earth, but data suggests that the particle energies are higher than those of the Van Allen belts and that the doses can be around a thousand times as intense<ref>Roussos, E., Allanson, O., André, N. et al. "The in-situ exploration of Jupiter’s radiation belts". <i>Experimental Astronomy</i> <b>54</b>, 745–789 (2022). https://doi.org/10.1007/s10686-021-09801-0</ref><ref>P. Kollmann, G. Clark, C. Paranicas, B. Mauk, E. Roussos, Q. Nénon, H. B. Garrett, A. Sicard, D. Haggerty, A. Rymer, "Jupiter's Ion Radiation Belts Inward of Europa's Orbit", <i>JGR Space Physics</i> Volume 126, Issue 4 (2021) https://doi.org/10.1029/2020JA028925</ref>.		Jupiter has one of the largest and strongest magnetic fields of any planet in the solar system. Like that of Earth, it will trap particles from the solar wind and the decay products of cosmic neutrons. However, what really sets Jupiter's radiation belts apart is what happens because of its moon, Io. Io is extremely volcanic, and regularly erupts fountains of sulfur dioxide into space. This gas is then ionized by ultraviolet sunlight, producing positively charged sulfur and oxygen ions. These ions spread out to form the <i>Io plasma torus</i>. Electric currents within the torus, driven by Jupiter's rotation, accelerates ions and electrons to high speeds and can produce dangerous radiation. Jupiter's radiation belts are not as well understood as those of Earth, but data suggests that the particle energies are higher than those of the Van Allen belts and that the doses can be around a thousand times as intense<ref>Roussos, E., Allanson, O., André, N. et al. "The in-situ exploration of Jupiter’s radiation belts". <i>Experimental Astronomy</i> <b>54</b>, 745–789 (2022). https://doi.org/10.1007/s10686-021-09801-0</ref><ref>P. Kollmann, G. Clark, C. Paranicas, B. Mauk, E. Roussos, Q. Nénon, H. B. Garrett, A. Sicard, D. Haggerty, A. Rymer, "Jupiter's Ion Radiation Belts Inward of Europa's Orbit", <i>JGR Space Physics</i> Volume 126, Issue 4 (2021) https://doi.org/10.1029/2020JA028925</ref>.
	The radiation is most intense closer to Jupiter, reaching a maximum of over 300 Gy/hour near Amalthea and other inner moons, approximately 20 Gy/hour at Io, 12 Gy/hour at Europa, 10 Gy/day (0.4 Gy/hour) at Ganymede, and 0.4 Gy/day at Callisto<ref name="Podzolko2013"></ref> (all assuming 10 kg/m² shielding). These doses are for the moon's orbits, presumably if you are on the moon the dose will be approximately halved (on average) because the moon will be shielding half the sky. However, the ~~interaction's~~ of the radiation with the moon's orbits is complicated, and generally one side (often the leading side) gets irradiated more than the other. This suggests that a spacecraft for a Jupiter mission could benefit from directional shielding, pointing its thicker shielded cap in the direction from which more radiation is incident – although you would still probably want substantial shielding from all directions!		The radiation is most intense closer to Jupiter, reaching a maximum of over 300 Gy/hour near Amalthea and other inner moons, approximately 20 Gy/hour at Io, 12 Gy/hour at Europa, 10 Gy/day (0.4 Gy/hour) at Ganymede, and 0.4 Gy/day at Callisto<ref name="Podzolko2013"></ref> (all assuming 10 kg/m² shielding). These doses are for the moon's orbits, presumably if you are on the moon the dose will be approximately halved (on average) because the moon will be shielding half the sky. However, the interactions of the radiation with the moon's orbits is complicated, and generally one side (often the leading side) gets irradiated more than the other. This suggests that a spacecraft for a Jupiter mission could benefit from directional shielding, pointing its thicker shielded cap in the direction from which more radiation is incident – although you would still probably want substantial shielding from all directions!
	[[File:Dose_rate_at_Ganymede_and_Europa_with_shielding.png\|thumb\|Dose rate at Europa and Ganymede orbit for different amounts of shielding<ref name="Podzolko2013"></ref>.]]		[[File:Dose_rate_at_Ganymede_and_Europa_with_shielding.png\|thumb\|Dose rate at Europa and Ganymede orbit for different amounts of shielding<ref name="Podzolko2013"></ref>.]]

Lwcamp: /* Electrostatic Shielding */

2026-03-13T02:12:39Z

Electrostatic Shielding

← Older revision		Revision as of 19:12, 12 March 2026
Line 245:		Line 245:
	But perhaps actually stopping the space radiation ions is not just too ambitious but also unnecessary. After all, what really matters is that the radiation doesn't get to you, not that it is stopped. If you are repelling the ions, any that isn't coming at you straight on will also be pushed off to the side a little bit. If enough of then get pushed away from you by a sufficient angle, maybe most of the particles will just miss you?<ref name="Tripathi2006">Ram K. Tripathi, John W. Wilson, and Robert C. Youngquist, "Electrostatic Active Radiation Shielding - Revisited", 2006 IEEE Aerospace Conference, Big Sky, MT, USA, 2006, pp. 9 pp.-, doi: 10.1109/AERO.2006.1655760.</ref> That's the idea behind a lot of the more current (2024) ideas for electrostatic shielding. These designs can use smaller electrodes charged to a lower overall voltage. You're still generally in the tens or hundreds of megavolts so you still have to deal with a lot of high voltages, you still need to supply electric power, and there are still concerns with space electrons discharging the shields and producing high energy radiation to affects the spacecraft. But deflection rather than absolute protection seems to be a more feasible option. One proposal<ref>Ram K. Tripathi, "Meeting the Grand Challenge of Protecting Astronaut’s Health: Electrostatic Active Space Radiation Shielding for Deep Space Missions", NASA NIAC 2011 Supported Study, Document ID 20160010094 https://ntrs.nasa.gov/citations/20160010094</ref> shows significant reduction even in high energy particle flux by using large electrodes in the shape of spheres or intersecting toroids made of a gossamer material that self-inflates once charged up (allowing it to be stowed and deployed as needed).		But perhaps actually stopping the space radiation ions is not just too ambitious but also unnecessary. After all, what really matters is that the radiation doesn't get to you, not that it is stopped. If you are repelling the ions, any that isn't coming at you straight on will also be pushed off to the side a little bit. If enough of then get pushed away from you by a sufficient angle, maybe most of the particles will just miss you?<ref name="Tripathi2006">Ram K. Tripathi, John W. Wilson, and Robert C. Youngquist, "Electrostatic Active Radiation Shielding - Revisited", 2006 IEEE Aerospace Conference, Big Sky, MT, USA, 2006, pp. 9 pp.-, doi: 10.1109/AERO.2006.1655760.</ref> That's the idea behind a lot of the more current (2024) ideas for electrostatic shielding. These designs can use smaller electrodes charged to a lower overall voltage. You're still generally in the tens or hundreds of megavolts so you still have to deal with a lot of high voltages, you still need to supply electric power, and there are still concerns with space electrons discharging the shields and producing high energy radiation to affects the spacecraft. But deflection rather than absolute protection seems to be a more feasible option. One proposal<ref>Ram K. Tripathi, "Meeting the Grand Challenge of Protecting Astronaut’s Health: Electrostatic Active Space Radiation Shielding for Deep Space Missions", NASA NIAC 2011 Supported Study, Document ID 20160010094 https://ntrs.nasa.gov/citations/20160010094</ref> shows significant reduction even in high energy particle flux by using large electrodes in the shape of spheres or intersecting toroids made of a gossamer material that self-inflates once charged up (allowing it to be stowed and deployed as needed).

	Improved computational techniques have allowed for rapid testing of shield concepts<ref name="Fry2020">D. Fry, M. Lund, A. A. Bahadori, R. Pal. Chowdhury, L. Stegeman, and S. Madzunkov, "Active Shielding Particle Pusher (ASPP): Charged-Particle Tracking Through Electromagnetic Fields", NASA/TP–2020–5002408 https://ntrs.nasa.gov/citations/20205002408</ref>, allowing for more efficient and effective designs for the same voltage. An array of positively charged plates and negatively charged rods held at a potential of several MV<ref name="Chowdhury2023">Rajarshi Pal Chowdhury, Luke A. Stegeman, Matthew L. Lund, Dan Fry, Stojan Madzunkov, and Amir A. Bahadori, "Hybrid methods of radiation shielding against deep-space radiation", Life Sciences in Space Research, Volume 38, 2023, Pages 67-78, ISSN 2214-5524, https://doi.org/10.1016/j.lssr.2023.04.004.</ref>; at about 15 MV potential difference it was predicted that the dose from a severe SPE could be reduced by approximately 30% to 50% over shielding alone. With an approximately 30 MV potential difference, on the order of 5% to 10% reduction in the dose from galactic cosmic rays at solar minimum was predicted over shielding alone. At the solar maximum, the difference even for 30 MV was negligible.		Improved computational techniques have allowed for rapid testing of shield concepts<ref name="Fry2020">D. Fry, M. Lund, A. A. Bahadori, R. Pal. Chowdhury, L. Stegeman, and S. Madzunkov, "Active Shielding Particle Pusher (ASPP): Charged-Particle Tracking Through Electromagnetic Fields", NASA/TP–2020–5002408 https://ntrs.nasa.gov/citations/20205002408</ref>, allowing for more efficient and effective designs for the same voltage. An array of positively charged plates and negatively charged rods held at a potential of several MV<ref name="Chowdhury2023">Rajarshi Pal Chowdhury, Luke A. Stegeman, Matthew L. Lund, Dan Fry, Stojan Madzunkov, and Amir A. Bahadori, "Hybrid methods of radiation shielding against deep-space radiation", Life Sciences in Space Research, Volume 38, 2023, Pages 67-78, ISSN 2214-5524, https://doi.org/10.1016/j.lssr.2023.04.004.</ref> at about 15 MV potential difference it was predicted that the dose from a severe SPE could be reduced by approximately 30% to 50% over shielding alone. With an approximately 30 MV potential difference, on the order of 5% to 10% reduction in the dose from galactic cosmic rays at solar minimum was predicted over shielding alone. At the solar maximum, the difference even for 30 MV was negligible.

	In addition, the power loss could be drastically reduced by using porous grids rather than solid electrodes. These allow the majority of the neutralizing particles to simply pass through rather than interact and discharge the electrodes. Such methods are reported to reduce the power requirement to approximately 100 Watts<ref>https://arstechnica.com/science/2024/03/shields-up-new-ideas-might-make-active-shielding-viable/</ref>.		In addition, the power loss could be drastically reduced by using porous grids rather than solid electrodes. These allow the majority of the neutralizing particles to simply pass through rather than interact and discharge the electrodes. Such methods are reported to reduce the power requirement to approximately 100 Watts<ref>https://arstechnica.com/science/2024/03/shields-up-new-ideas-might-make-active-shielding-viable/</ref>.

Lwcamp: /* Passive Shielding */

2026-03-13T02:05:01Z

Passive Shielding

← Older revision		Revision as of 19:05, 12 March 2026
Line 225:		Line 225:
	=== Passive Shielding ===		=== Passive Shielding ===

	But maybe you want something more sure than trying to avoid or tough out the radiation. Shielding is the usual answer. This usually involves putting layers of stuff around your spacecraft to block the radiation before it gets to you. Or at least around the parts of the spacecraft that have stuff that you want to protect. In the descriptions of the various kinds of space radiation, we have tried to give an idea of how much shielding you need to reduce the dose (or dose rate) to whatever you decide is an acceptable level. Particle radiation is best stopped with hydrogen rich stuff or at least light elements because this reduces the radiation cascades that make showers of secondary particles. X-ray or gamma radiation, on the other hand, is best stopped with heavy elements – so you might want to try to reduce the particle radiation as much as possible with shielding on the outside before it gets to the heavy metal photon shielding layer. The problem with shielding is that it is heavy. With anything like today's technology, that makes it prohibitive to have much shielding beyond a basic spacecraft structural hull. Any shielding can help some by screening out the lower energy particles, and radiation environments with lower energy particles (such as planetary radiation belts or solar particle events) might be feasible to fully shield with reasonable advances in rocketry capability. The high energy cosmic rays, however, are a significant challenge and it may be necessary to tolerate some degree of elevated cosmic ray dose for interplanetary trips if the alternative is so much shielding that you can't go at all.		But maybe you want something more sure than trying to avoid or tough out the radiation. Shielding is the usual answer. This usually involves putting layers of stuff around your spacecraft to block the radiation before it gets to you. Or at least around the parts of the spacecraft that have stuff that you want to protect. In the descriptions of the various kinds of space radiation, we have tried to give an idea of how much shielding you need to reduce the dose (or dose rate) to whatever you decide is an acceptable level. Particle radiation is best stopped with hydrogen rich stuff or at least light elements because this reduces the radiation cascades that make showers of secondary particles. X-ray or gamma radiation, on the other hand, is best stopped with heavy elements – so you might want to try to reduce the particle radiation as much as possible with shielding on the outside before it gets to the heavy metal photon shielding layer. The problem with shielding is that it is heavy. With anything like today's rocket technology, that makes it prohibitive to have much shielding beyond a basic spacecraft structural hull. Any shielding can help some by screening out the lower energy particles, and radiation environments with lower energy particles (such as planetary radiation belts or solar particle events) might be feasible to fully shield with reasonable advances in rocketry capability. The high energy cosmic rays, however, are a significant challenge and it may be necessary to tolerate some degree of elevated cosmic ray dose for interplanetary trips if the alternative is so much shielding that you can't go at all.

	=== Active Shielding ===		=== Active Shielding ===

Lwcamp: /* Black Holes */

2026-03-13T01:41:53Z

Black Holes

← Older revision		Revision as of 18:41, 12 March 2026
Line 195:		Line 195:
	=== Black Holes ===		=== Black Holes ===

	An isolated stellar mass black hole is cold, quiescent, and lacking activity – radioactivity or otherwise. The interesting stuff happens when the black hole is not isolated.		An isolated stellar mass [[Black_Hole_Engineering\|black hole]] is cold, quiescent, and lacking activity – radioactivity or otherwise. The interesting stuff happens when the black hole is not isolated.

	Material attracted by the black hole's gravity will spiral around to form an accretion disk. As the material falls deeper into the disk, it will be heated by the shear flow of the neighboring gas to produce intense thermal x-rays and gamma rays. Up to approximately 5 to 30% of the mass-energy of infalling material can be radiated away, such that an actively eating black hole can be a source of intense radiation. In addition, much as with a neutron star, the accretion disk can produce an astrophysical jet of intense particle radiation and associated x-ray and gamma ray emissions.		Material attracted by the black hole's gravity will spiral around to form an accretion disk. As the material falls deeper into the disk, it will be heated by the shear flow of the neighboring gas to produce intense thermal x-rays and gamma rays. Up to approximately 5 to 40% of the mass-energy of infalling material can be radiated away, such that an actively eating black hole can be a source of intense radiation. In addition, much as with a neutron star, the accretion disk can produce an astrophysical jet of intense particle radiation and associated x-ray and gamma ray emissions.

	The largest black holes known are the <i>supermassive black holes</i>, one of which sits in the heart of every galaxy. These behemoths can have accretion disks made of many stars and their associated solar systems at once, all of which have been torn to pieces and are spinning down the drain of oblivion. The most active supermassive black holes are quasars, which can consume between ten and a thousand suns worth of material a year. These are the brightest known objects in the universe, and are certain to be some of the most extreme persistent radiation environments in existence.		The largest black holes known are the <i>supermassive black holes</i>, one of which sits in the heart of every galaxy. These behemoths can have accretion disks made of many stars and their associated solar systems at once, all of which have been torn to pieces and are spinning down the drain of oblivion. The most active supermassive black holes are quasars, which can consume between ten and a thousand suns worth of material a year. These are the brightest known objects in the universe, and are certain to be some of the most extreme persistent radiation environments in existence.

Lwcamp at 19:06, 7 March 2026

2026-03-07T19:06:08Z

← Older revision		Revision as of 12:06, 7 March 2026
Line 326:		Line 326:
	== References ==		== References ==

	[[Category:Habitation]][[Category:Physics & Engineering]]		[[Category:Habitation]][[Category:Physics & Engineering]][[Category:Physics & Math & Engineering]]

Lwcamp: /* Shielding Against Cosmic Rays */

2025-10-20T14:26:11Z

Shielding Against Cosmic Rays

← Older revision		Revision as of 07:26, 20 October 2025
Line 45:		Line 45:
	[[File:GCR_Shielding_comparison.png\|350 px\|frameless]]		[[File:GCR_Shielding_comparison.png\|350 px\|frameless]]
	<tr><td width=350>		<tr><td width=350>
	Comparison of aluminum, lunar regolith, and polyethyene shielding as a function of thickness at both solar ~~maximum~~ (solid lines) and solar ~~minimum~~ (dashed lines) galactic cosmic ray conditions<ref name="Horst2022"></ref>.		Comparison of aluminum, lunar regolith, and polyethyene shielding as a function of thickness at both solar minimum (solid lines) and solar maximum (dashed lines) galactic cosmic ray conditions<ref name="Horst2022"></ref>.
	</table>		</table>
	</div>		</div>

Lwcamp: /* Black Holes */

2025-08-16T05:26:24Z

Black Holes

← Older revision		Revision as of 22:26, 15 August 2025
Line 199:		Line 199:
	Material attracted by the black hole's gravity will spiral around to form an accretion disk. As the material falls deeper into the disk, it will be heated by the shear flow of the neighboring gas to produce intense thermal x-rays and gamma rays. Up to approximately 5 to 30% of the mass-energy of infalling material can be radiated away, such that an actively eating black hole can be a source of intense radiation. In addition, much as with a neutron star, the accretion disk can produce an astrophysical jet of intense particle radiation and associated x-ray and gamma ray emissions.		Material attracted by the black hole's gravity will spiral around to form an accretion disk. As the material falls deeper into the disk, it will be heated by the shear flow of the neighboring gas to produce intense thermal x-rays and gamma rays. Up to approximately 5 to 30% of the mass-energy of infalling material can be radiated away, such that an actively eating black hole can be a source of intense radiation. In addition, much as with a neutron star, the accretion disk can produce an astrophysical jet of intense particle radiation and associated x-ray and gamma ray emissions.

	The largest black holes known are the <i>supermassive black holes</i>, one of which sits in the ~~hear~~ of every galaxy. These behemoths can have accretion disks made of many stars and their associated solar systems at once, all of which have been torn to pieces and are spinning down the drain of oblivion. The most active supermassive black holes are quasars, which can consume between ten and a thousand suns worth of material a year. These are the brightest known objects in the universe, and are certain to be some of the most extreme persistent radiation environments in existence.		The largest black holes known are the <i>supermassive black holes</i>, one of which sits in the heart of every galaxy. These behemoths can have accretion disks made of many stars and their associated solar systems at once, all of which have been torn to pieces and are spinning down the drain of oblivion. The most active supermassive black holes are quasars, which can consume between ten and a thousand suns worth of material a year. These are the brightest known objects in the universe, and are certain to be some of the most extreme persistent radiation environments in existence.

	=== Supernovas ===		=== Supernovas ===

Lwcamp: /* White Dwarfs */

2025-08-16T05:20:17Z

White Dwarfs

← Older revision		Revision as of 22:20, 15 August 2025
Line 173:		Line 173:
	=== White Dwarfs ===		=== White Dwarfs ===

	A young white dwarf will be much less luminous than its parent star. However, it will be much hotter with most of its radiated power in the ultraviolet and soft x-ray regions of the spectrum. Radiation of this nature can be dangerous to unprotected skin, but then so is space so this feature is probably not much of a concern. The shielding of even a space suit or ~~thing~~ spacecraft hull should suffice for protection. As the white dwarf cools, both the luminosity and the proportion of its emitted heat as x-rays and ultraviolet drops.		A young white dwarf will be much less luminous than its parent star. However, it will be much hotter with most of its radiated power in the ultraviolet and soft x-ray regions of the spectrum. Radiation of this nature can be dangerous to unprotected skin, but then so is space so this feature is probably not much of a concern. The shielding of even a space suit or thin spacecraft hull should suffice for protection. As the white dwarf cools, both the luminosity and the proportion of its emitted heat as x-rays and ultraviolet drops.

	White dwarfs have magnetic fields ranging from between 0.2 T and 100 kT. This is well above the field of Earth, which raises the possibility of strong radiation belts around these objects.		White dwarfs have magnetic fields ranging from between 0.2 T and 100 kT. This is well above the field of Earth, which raises the possibility of strong radiation belts around these objects.

Lwcamp: /* Solar Flares */

2025-08-16T05:07:08Z

Solar Flares

← Older revision		Revision as of 22:07, 15 August 2025
Line 78:		Line 78:
	It is estimated that solar flares which deliver a dangerous dose of SEPs are roughly 50 times less frequent than those which deliver a dangerous x-ray dose<ref name="Smith2007"></ref>. Still, the dose from flare SEPs can still be dangerous<ref>T. Sato, "Recent progress in space weather research for cosmic radiation dosimetry", Annals of the ICRP Volume 49, Issue 1_suppl (2020) https://doi.org/10.1177/0146645320933401</ref>.		It is estimated that solar flares which deliver a dangerous dose of SEPs are roughly 50 times less frequent than those which deliver a dangerous x-ray dose<ref name="Smith2007"></ref>. Still, the dose from flare SEPs can still be dangerous<ref>T. Sato, "Recent progress in space weather research for cosmic radiation dosimetry", Annals of the ICRP Volume 49, Issue 1_suppl (2020) https://doi.org/10.1177/0146645320933401</ref>.

	Solar flares occur more frequently during the solar maximum of the 11-year sunspot cycle. Sunspots happen ~~with~~ strong bundles of trapped magnetic fields emerge from the sun's atmosphere. Consequently, solar flares often occur near sunspots.		Solar flares occur more frequently during the solar maximum of the 11-year sunspot cycle. Sunspots happen where strong bundles of trapped magnetic fields emerge from the sun's atmosphere. Consequently, solar flares often occur near sunspots.

	The x-rays from solar flares are best shielded using heavy elements. This is the opposite of shielding against particle radiation (such as galactic cosmic rays, SEPs, or radiation belt particles) where heavy elements can end up making things worse. If you are going to shield against x-rays you might consider putting a thin layer of heavy metal on the <i>inside</i> of your particle shielding, where the particle shower has hopefully already attenuated into low enough energy particles to not significantly multiply within your x-ray shield.		The x-rays from solar flares are best shielded using heavy elements. This is the opposite of shielding against particle radiation (such as galactic cosmic rays, SEPs, or radiation belt particles) where heavy elements can end up making things worse. If you are going to shield against x-rays you might consider putting a thin layer of heavy metal on the <i>inside</i> of your particle shielding, where the particle shower has hopefully already attenuated into low enough energy particles to not significantly multiply within your x-ray shield.

Lwcamp: /* Galactic Cosmic Rays */

2025-05-26T16:02:04Z

Galactic Cosmic Rays

← Older revision		Revision as of 09:02, 26 May 2025
Line 13:		Line 13:
	Cosmic rays come through at a steady sleet, delivering on the order of 1 – 2.5 mSv/day<ref name="CRaTER update">https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015SW001175 Mazur, J. E., C. Zeitlin, N. Schwadron, M. D. Looper, L. W. Townsend, J. B. Blake, and H. Spence (2015), "Update on Radiation Dose From Galactic and Solar Protons at the Moon Using the LRO/CRaTER Microdosimeter", Space Weather, 13, 363–364, doi:10.1002/2015SW001175. The values given here are corrected for the roughly 2 π steradian shielding afforded by the moon and modified for relative biological effectiveness.</ref><ref name="Cucinotta">[https://ntrs.nasa.gov/api/citations/20070010704/downloads/20070010704.pdf Francis A. Cucinotta, "Space Radiation Organ Doses for Astronauts on Past and Future Missions"]</ref>. This dose is not delivered fast enough to cause [[Nuclear_radiation#Acute\|acute radiation sickness]], but is roughly two orders of magnitude higher than the natural background radiation dose on Earth. This can cause issues with [[Nuclear_radiation#Chronic\|chronic radiation]] exposure. The main concern is an increased risk of cancer. However, experiments on rodents exposed to radiation from a particle beam simulating long duration exposure to cosmic radiation also suggests the possibility of reduced cognitive function after several months in deep space<ref name="cognitive dysfunction">https://www.nature.com/articles/srep34774 Vipan K. Parihar, Barrett D. Allen, Chongshan Caressi, Stephanie Kwok, Esther Chu, Katherine K. Tran, Nicole N. Chmielewski, Erich Giedzinski, Munjal M. Acharya, Richard A. Britten, Janet E. Baulch, and Charles L. Limoli, "Cosmic radiation exposure and persistent cognitive dysfunction", <i>Scientific Reports</i> <b>6</b>, 34774 (2016). https://doi.org/10.1038/srep34774</ref>. The cosmic ray dose rate is lower in times of high solar activity as the increased solar wind prevents more cosmic rays from entering our solar system. A planetary magnetosphere like that of Earth can deflect enough of the lower energy cosmic rays to make a noticeable difference in the dose rate<ref name="Cucinotta"></ref>, often in the 0.2 – 1 mSv/day range in low orbits below the main radiation belts, although this depends strongly on the latitudes through which the satellite passes. Equatorial orbits offer the best protection, and polar orbits pass through the radiation belts where the cosmic rays are deflected to. A significant amount of this shielding is also afforded by the planet itself, which will block cosmic rays from close to half the sky for close orbits.		Cosmic rays come through at a steady sleet, delivering on the order of 1 – 2.5 mSv/day<ref name="CRaTER update">https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015SW001175 Mazur, J. E., C. Zeitlin, N. Schwadron, M. D. Looper, L. W. Townsend, J. B. Blake, and H. Spence (2015), "Update on Radiation Dose From Galactic and Solar Protons at the Moon Using the LRO/CRaTER Microdosimeter", Space Weather, 13, 363–364, doi:10.1002/2015SW001175. The values given here are corrected for the roughly 2 π steradian shielding afforded by the moon and modified for relative biological effectiveness.</ref><ref name="Cucinotta">[https://ntrs.nasa.gov/api/citations/20070010704/downloads/20070010704.pdf Francis A. Cucinotta, "Space Radiation Organ Doses for Astronauts on Past and Future Missions"]</ref>. This dose is not delivered fast enough to cause [[Nuclear_radiation#Acute\|acute radiation sickness]], but is roughly two orders of magnitude higher than the natural background radiation dose on Earth. This can cause issues with [[Nuclear_radiation#Chronic\|chronic radiation]] exposure. The main concern is an increased risk of cancer. However, experiments on rodents exposed to radiation from a particle beam simulating long duration exposure to cosmic radiation also suggests the possibility of reduced cognitive function after several months in deep space<ref name="cognitive dysfunction">https://www.nature.com/articles/srep34774 Vipan K. Parihar, Barrett D. Allen, Chongshan Caressi, Stephanie Kwok, Esther Chu, Katherine K. Tran, Nicole N. Chmielewski, Erich Giedzinski, Munjal M. Acharya, Richard A. Britten, Janet E. Baulch, and Charles L. Limoli, "Cosmic radiation exposure and persistent cognitive dysfunction", <i>Scientific Reports</i> <b>6</b>, 34774 (2016). https://doi.org/10.1038/srep34774</ref>. The cosmic ray dose rate is lower in times of high solar activity as the increased solar wind prevents more cosmic rays from entering our solar system. A planetary magnetosphere like that of Earth can deflect enough of the lower energy cosmic rays to make a noticeable difference in the dose rate<ref name="Cucinotta"></ref>, often in the 0.2 – 1 mSv/day range in low orbits below the main radiation belts, although this depends strongly on the latitudes through which the satellite passes. Equatorial orbits offer the best protection, and polar orbits pass through the radiation belts where the cosmic rays are deflected to. A significant amount of this shielding is also afforded by the planet itself, which will block cosmic rays from close to half the sky for close orbits.

	Cosmic rays passing through a computer chip can cause transient errors that can result in a glitch in operations or a corrupted bit of memory. [[Nuclear_radiation#Electronics_effects\|High doses of radiation can also cause permanent damage to ~~elctronics~~]].		Cosmic rays passing through a computer chip can cause transient errors that can result in a glitch in operations or a corrupted bit of memory. [[Nuclear_radiation#Electronics_effects\|High doses of radiation can also cause permanent damage to electronics]].

	=== Shielding Against Cosmic Rays ===		=== Shielding Against Cosmic Rays ===