Editing Galileo project (section)

===Radiation-related anomalies===
[[File:Jupiter's Magnetosphere animation.png|thumb|left|Jupiter's inner magnetosphere and radiation belts|alt=lines of magnetism come from the poles and loop around.]]
Jupiter's uniquely harsh radiation environment caused over 20 anomalies over the course of ''Galileo''{{'s}} mission, in addition to the incidents expanded upon below. Despite having exceeded its radiation design limit by at least a factor of three, the spacecraft survived all these anomalies. Work-arounds were found eventually for all of these problems, and ''Galileo'' was never rendered entirely non-functional by Jupiter's radiation. The radiation limits for ''Galileo''{{'s}} computers were based on data returned from ''[[Pioneer 10]]'' and ''[[Pioneer 11]]'', since much of the design work was underway before the two ''Voyagers'' arrived at Jupiter in 1979.{{sfn|Tomayko|1988|p=200}}

A typical effect of the radiation was that several of the science instruments suffered increased [[signal-to-noise ratio|noise]] while within about {{convert|700000|km|mi|abbr=on}} of Jupiter. The SSI camera began producing totally white images when the spacecraft was hit by the exceptional [[Bastille Day event|Bastille Day coronal mass ejection]] in 2000, and did so again on subsequent close approaches to Jupiter.{{sfn|Fieseler|Ardalan|Frederickson|2002|pp=2748–2751}} The quartz crystal used as the frequency reference for the radio suffered permanent frequency shifts with each Jupiter approach.{{sfn|Fieseler|Ardalan|Frederickson|2002|pp=2743–2744}} A spin detector failed, and the spacecraft gyro output was biased by the radiation environment.{{sfn|Fieseler|Ardalan|Frederickson|2002|pp=2744–2746}}

The most severe effects of the radiation were current leakages somewhere in the spacecraft's power bus, most likely across [[Brush (electric)|brushes]] at a [[Bearing (mechanical)|spin bearing]] connecting rotor and stator sections of the orbiter. These current leakages triggered a reset of the onboard computer and caused it to go into safe mode. The resets occurred when the spacecraft was either close to Jupiter or in the region of space magnetically downstream of Jupiter. A change to the software was made in April 1999 that allowed the onboard computer to detect these resets and autonomously recover, so as to avoid safe mode.<ref>{{cite web |url=http://starbase.jpl.nasa.gov/go-a-nims-3-tube-v1.0/go_1117/catalog/insthost.cat~ |title=Instrument Host Overview |publisher=NASA/Jet Propulsion Laboratory |date=1999 |access-date=November 29, 2012 |url-status=dead |archive-url=https://web.archive.org/web/20160315192151/http://starbase.jpl.nasa.gov/go-a-nims-3-tube-v1.0/go_1117/catalog/insthost.cat~ |archive-date=March 15, 2016}}</ref>