Editing Voyager program (section)

===Power===
[[File:MHW-RTGs.gif|right|thumb|[[Radioisotope thermoelectric generator|RTGs]] for the Voyager program|238x238px]]
[[electric power|Electrical power]] is supplied by three [[MHW-RTG]] [[radioisotope thermoelectric generator]]s (RTGs). They are powered by [[plutonium-238]] (distinct from the [[Plutonium-239|Pu-239]] isotope used in nuclear weapons) and provided approximately 470 [[Watt|W]] at 30 [[volt]]s [[direct current|DC]] when the spacecraft was launched. Plutonium-238 decays with a [[half-life]] of 87.74 years,<ref>{{Cite web|url=https://lanl.gov/source/orgs/nmt/nmtdo/AQarchive/97summer/Pu_238.html|title=The Actinide Research Quarterly: Summer 1997|website=lanl.gov|access-date=6 February 2020|archive-date=8 March 2022|archive-url=https://web.archive.org/web/20220308131514/https://lanl.gov/source/orgs/nmt/nmtdo/AQarchive/97summer/Pu_238.html|url-status=live}}</ref> so RTGs using Pu-238 will lose a factor of 1−0.5<sup>(1/87.74)</sup> = 0.79% of their power output per year.

In 2011, 34 years after launch, the thermal power generated by such an RTG would be reduced to (1/2)<sup>(34/87.74)</sup> ≈ 76% of its initial power. The RTG [[thermocouple]]s, which convert thermal power into electricity, also degrade over time reducing available electric power below this calculated level.

By 7 October 2011 the power generated by ''Voyager 1'' and ''Voyager 2'' had dropped to 267.9 W and 269.2 W respectively, about 57% of the power at launch. The level of power output was better than pre-launch predictions based on a conservative thermocouple degradation model. As the electrical power decreases, spacecraft loads must be turned off, eliminating some capabilities. There may be insufficient power for communications by 2032.<ref>{{cite news|last1=Segal|first1=Michael|title=Beyond Voyager|url=http://nautil.us/issue/51/limits/beyond-voyager|access-date=2 September 2017|work=[[Nautilus (science magazine)|Nautilus]]|date=1 September 2017|archive-date=2 September 2017|archive-url=https://web.archive.org/web/20170902052932/http://nautil.us/issue/51/limits/beyond-voyager|url-status=dead}}</ref>
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