Editing Van Allen radiation belt (section)

==Implications for space travel==
{{Comparison_satellite_navigation_orbits}}
Spacecraft travelling beyond [[low Earth orbit]] enter the zone of radiation of the Van Allen belts. Beyond the belts, they face additional hazards from cosmic rays and [[solar particle event]]s. A region between the inner and outer Van Allen belts lies at 2 to 4 Earth radii and is sometimes referred to as the "safe zone".<ref>{{cite web
 | title=Earth's Radiation Belts with Safe Zone Orbit
 | date=15 December 2004
 | publisher=NASA/GSFC
 | url=http://svs.gsfc.nasa.gov/vis/a000000/a003000/a003052/index.html
 | access-date=2009-04-27
 | archive-date=2016-01-13
 | archive-url=https://web.archive.org/web/20160113122436/http://svs.gsfc.nasa.gov/vis/a000000/a003000/a003052/index.html
 | url-status=dead
 }}</ref><ref>{{cite web | first=Rachel A. | last=Weintraub | title=Earth's Safe Zone Became Hot Zone During Legendary Solar Storms | date=December 15, 2004 | publisher=NASA/GSFC | url=http://www.nasa.gov/vision/universe/solarsystem/safe_zone.html | access-date=2009-04-27 | archive-date=2016-05-07 | archive-url=https://web.archive.org/web/20160507111835/http://www.nasa.gov/vision/universe/solarsystem/safe_zone.html | url-status=dead }}</ref>

[[Solar cell]]s, [[integrated circuit]]s, and [[sensor]]s can be damaged by radiation. Geomagnetic storms occasionally damage [[electronics|electronic]] components on spacecraft. Miniaturization and [[Digital electronics|digitization]] of electronics and [[logic gate|logic circuit]]s have made satellites more vulnerable to radiation, as the total [[electric charge]] in these circuits is now small enough so as to be comparable with the charge of incoming ions. Electronics on satellites must be [[Radiation hardening|hardened]] against radiation to operate reliably. The [[Chandra Space Telescope]], has its sensors turned off when passing through the Van Allen belts.<ref>{{Cite web |title=Chandra Observatory Launch Lights Up the Night Sky |url=https://imagine.gsfc.nasa.gov/news/23jul99.html |archive-url=https://web.archive.org/web/20241216065723/https://imagine.gsfc.nasa.gov/news/23jul99.html |archive-date=2024-12-16 |access-date=2025-03-23 |website=imagine.gsfc.nasa.gov}}</ref> The [[INTEGRAL]] space telescope was placed in an orbit designed to avoid time within the belts.<ref>{{Cite web |title=Imagine the Universe News - 17 October 2002 |url=https://imagine.gsfc.nasa.gov/news/17oct02.html |access-date=2025-03-23 |website=imagine.gsfc.nasa.gov}}</ref>

The [[List of Apollo missions|Apollo missions]] marked the first event where humans traveled through the Van Allen belts, which was one of several radiation hazards known by mission planners.<ref name=Vernon>{{cite web|last=Bailey|first=J. Vernon|title=Radiation Protection and Instrumentation|url=https://history.nasa.gov/SP-368/s2ch3.htm|work=Biomedical Results of Apollo|date=January 1975 |volume=NASA-SP-368 |access-date=2011-06-13}}</ref> The astronauts had low exposure in the Van Allen belts due to the short period of time spent flying through them.<ref name="popsci.com"/><ref name=Woods>{{Cite book| last=Woods| first=W. David| title=How Apollo Flew to the Moon| date=2008| publisher=[[Springer Science+Business Media|Springer-Verlag]]| location=New York| isbn=978-0-387-71675-6| page=[https://archive.org/details/howapolloflewtom0000wood/page/109 109]| url=https://archive.org/details/howapolloflewtom0000wood/page/109}}</ref>