nuclear undone
  • blog
  • about
  • contact

undo your thinking

listen to the facts

absorb new ideas

Why hasn't Voyager 1 run out of power yet?

3/14/2014

1 Comment

 
By Lenka Kollar

One of my Facebook friends posted the above question and I thought it was a very valid thing to ask. In a world where we have to fill up our cars once (or more) a week, replace phone batteries after two years, and receive a constant supply of electricity to our homes, it's hard to imagine that a spacecraft that was launched in 1977 still has power.
Picture
The instruments on Voyager I are powered by three radioisotope thermoelectric generators (RTGs). An RTG contains a plutonium-238 source, which decays by alpha particles thus and produces heat. This heat is converted by thermocouples and a generator into electricity. An RTG isn't a nuclear reactor because the isotope is not fissioning, but this is a great alternative use of nuclear technology.

Voyager I was just reported to leave the solar system, the first man-made object to do so. The spacecraft measures cosmic rays and magnetic fields and sends the data back to Earth to be analyzed by NASA scientists. They will continue to receive data form Voyager I until the power runs out in 2025. 
1 Comment
Damon Bryson
3/14/2014 03:02:24 am

Each Voyager probe used three Multihundred Watt (MHW) RTG made by General Electric, each rated 2400 W thermal and 150 W electric. They were an upgrade to silicon germanium thermoelectric converters with an efficiency of 6.7%. Due to the 88 year half life of Pu-238, the heat output decays by about 1% per year. Voyager 1's RTGs were each still producing 140 W after 5 years of operation. Each RTG only weighs 38.5 kg.

Unfortunately Pu-238 production capacity is very limited, so NASA does not have enough available to support very many missions. The Mars rover Curiosity required over half the remaining stockpile (which was purchased from Russia). DOE is starting to produce more Pu-238 in the next few years.

Reply



Leave a Reply.

    Picture

    Archives

    January 2017
    December 2016
    November 2016
    October 2016
    August 2016
    June 2016
    May 2016
    February 2016
    January 2016
    October 2015
    September 2015
    August 2015
    July 2015
    June 2015
    May 2015
    April 2015
    March 2015
    February 2015
    January 2015
    December 2014
    November 2014
    October 2014
    September 2014
    August 2014
    July 2014
    June 2014
    May 2014
    April 2014
    March 2014
    February 2014
    January 2014
    December 2013
    November 2013
    October 2013

    Categories

    All
    American Nuclear Society
    Climate Change
    Diversity In Stem
    Energy
    Environmentalists
    Fuel Cycle
    I'm A Nuke
    International
    IYNC
    Navy
    Nonproliferation
    Nuclear Energy
    Nuclear Energy
    Nuclear Engineers
    Nuclear Technology
    Policy
    Radiation
    Reactors
    Science Education
    Sustainability
    UAE
    Women In Engineering

    RSS Feed


    Follow on Bloglovin
Powered by Create your own unique website with customizable templates.
Photos used under Creative Commons from Idaho National Laboratory, Jim.Richmond, Idaho National Laboratory, IAEA Imagebank