How Spacecraft Fly
  • Home
  • About the author
  • What's it all about?
  • Reviews
  • Picture gallery
  • External links
  • Contact me
  • Author's blog
  • Correction to text

Celebration of 35 years of flight operations for Voyager

10/25/2012

1 Comment

 
Picture
After launch in 1977, the two Voyager spacecraft have now been operating in a hostile space environment for an amazing 35 years.  

The launch date was chosen to take advantage of a particular planetary alignment that occurs only once every 176 years.  This opportunity to visit the four major planets – Jupiter, Saturn, Uranus and Neptune – in one 12 year mission was originally identified by a JPL spacecraft engineer Gary Flandro.  Prior to this, a mathematics graduate Micheal Minovitch had studied the dynamics of gravity assists (see page 71 of How Spacecraft Fly), and the two threads came together as proposal to fly the Voyager missions.  Using more conventional methods, such a mission would have taken anything up to 30 years to reach distant Neptune.  But with each successive swing-by, the spacecraft received a boost in Sun-relative speed to enable a complete tour of the four major planets within a period of time which allowed a reasonable probability that the spacecraft would still be functional at destination. A chart of the speed profile for Voyager 2 can be found on page 75 of How Spacecraft Fly.

The mass of the Voyager spacecraft was around 700 kg, with a ‘beginning of life’ power of 420 W from 3 RTGs (radioisotope thermal generators). Voyager 2 (V2) was actually launched first on 20 August 1977, followed days later by the launch of Voyager 1 (V1) on 5 September.  However V1 reached Jupiter and Saturn before V2.  The V2 spacecraft then went on to visit Uranus and Neptune as well, the only spacecraft to date ever to do so.

Currently, after their 35 year mission, V1 is around 18 billion km (18,000,000,000) from the Sun in a position North of the Earth’s orbit plane, and V2 is 15 billion km distant, South of the plane.  This is around 120 AU and 100 AU respectively.  There is currently some excitement about the proximity of V1, in particular, to the heliopause.   This is the boundary between the physical sphere of influence of the Sun and interstellar space.  Onboard instruments are recording an increase in high-energy particles from outside the sphere of influence, while simultaneously registering a dip in low-energy particles emanating from the Sun.  It is anticipated that V1 could become the first man-made object to enter interstellar space in the next 5 years or so.  The engineers at JPL anticipate that the spacecraft has sufficient electrical power to continue operations until about 2020.

Voyager has been an amazingly successful programme in terms of the huge volume of scientific data collected during the ‘grand tour’of the major planets.  Along the way the 2 spacecraft have given us many beautiful images of these stage worlds, and made discoveries beyond our imagination. In terms of the major astronautical achievements of the 20th Century, I would rate Voyager in the top three, along with Sputnik 1, and Apollo.  Voyager is now, however, a 21st Century phenomenon as well!


Picture
Illustration of the Voyager spacecraft configuration.  To give an idea of scale, the antenna is about 3.7 m (12 feet) in diameter

Picture
Schematic giving approximate positions of the Voyager spacecraft relative to 'interstellar space'

1 Comment
annakiss link
10/30/2013 01:13:40 am

Great blog post, thanks for posting this.

Reply



Leave a Reply.

    Author

    Graham Swinerd - I hope to use this page to highlight current major events in space and spacececraft.

    Archives

    November 2024
    November 2022
    October 2016
    July 2016
    February 2016
    December 2015
    September 2015
    July 2015
    June 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
    July 2013
    May 2013
    April 2013
    March 2013
    December 2012
    October 2012
    September 2012
    August 2012
    July 2012
    June 2012
    May 2012
    April 2012
    January 2012
    October 2011
    August 2011
    July 2011
    June 2011
    May 2011
    April 2011
    March 2011
    February 2011
    January 2011

    Categories

    All

    RSS Feed

Powered by Create your own unique website with customizable templates.