Pioneer 10, Pioneer 11, and the two Voyagers are all headed out of the solar system. Has anybody extrapolated where they will all end up (if at all)? Is there a graphic that depicts the direction of flight of all four spacecraft?


3 Answers 3


Besides "beyond the heliopause", they are not ultimately headed towards anything in particular. The sparsity of the universe and even our galaxy means that they are unlikely to encounter much of anything without being specifically targeted for it (which is out of the question at this point).

This paper addresses this question more specifically (for Pioneer 10 and 11, at least). It states that Pioneer 10 is headed in the general direction of the star Aldebaran (part of the Taurus constellation) (which it will "reach" in about 2 million years), and Pioneer 11 "should pass close to the nearest star in the constellation Aquila in about 4 million years".

As far as the Voyagers:

Voyager 1 will drift within 1.6 light-years (9.3 trillion miles) of AC+79 3888, a star in the constellation of Camelopardalis which is heading toward the constellation Ophiuchus. In about 40,000 years, Voyager 2 will pass 1.7 light-years (9.7 trillion miles) from the star Ross 248 and in about 296,000 years, it will pass 4.3 light-years (25 trillion miles) from Sirius, the brightest star in the sky . The Voyagers are destined—perhaps eternally—to wander the Milky Way.

This page gives a nice overview of the relative positions of these probes as of 2011:

Voyager 1 is the most distant spacecraft, about 17.5 billion kilometers (10.9 billion miles) away from the sun at a northward angle. Pioneer 10, the next most distant, is about 15.4 billion kilometers (9.6 billion miles) away from the sun on the opposite side of the solar system. Voyager 2 is about 14.2 billion kilometers (8.8 billion miles) away from the sun on a southward trajectory, on the same side of the solar system as Voyager 1. Pioneer 11 is about 12.4 billion kilometers (7.8 billion miles) away from the sun. relative probe positions

Heavens Above has a slightly better graphic, IMO:

enter image description here

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    $\begingroup$ I like the first graphic better since it alos depicts that the Voyagers are well outside the plane of the ecliptic and thus much farther from P11 and the sun that the second graphic implies. $\endgroup$ Aug 27, 2013 at 19:12
  • $\begingroup$ If you used both of heaven above's images from the link I'd agree with your assessment. $\endgroup$ Aug 27, 2013 at 19:14
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    $\begingroup$ I find it very reassuring that my brethren will be able to also see the grandeur of the Voyager 1. "Voyager 1 will drift within 1.6 light-years (9.3 trillion miles) of AC+79 3888, a star in the constellation of Camelopard-alis". I will communicate with them to launch the welcome probe immediately. $\endgroup$ Aug 27, 2013 at 20:37
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    $\begingroup$ All of these probes have already passed within 4.3 ly of Proxima Centauri, and within 4.4 ly of Alpha Centauri. $\endgroup$
    – user
    Jan 22, 2016 at 13:34

Here is a helpful image I received from Dr Lasher from one of his AIAA astrodynamics papers from the 1970's it reflects the Jupiter aim points for the Star 37E after separation from the Centaur upper stage for the pioneer spacecraft. enter image description here

The B plane of a planet is always changing do to spacecraft incoming speed and line of flight(geometry) and epoch(time) notice the upper stage did not do such a good job with Pioneer 11 so Pioneer 11 had to do a TCM-1 to move the spacecraft over to the Hyperbolic circle on the right.so in this case the pioneer 11 Star 37E solid upper stage is in a heliocentric orbit while Pioneer 11 went to a Saturn flyby into interstellor space.

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    $\begingroup$ Thank you, this is an intriguing chart, its really woken me up! Could you help out a little with some definitions please? What is the B-plane? Where you say "upper stage did not do such a good job" are you referring to the Centaur rather than the Star? What is the meaning of the larger circle "Departure from Jupiter Heliocentric Radial Component = IN"? $\endgroup$
    – Puffin
    Jan 22, 2016 at 13:47
  • $\begingroup$ Puffin here is a very visual explanation of what the B Plane is as viewed by an incoming spacecraft ccar.colorado.edu/ASEN5070/lectures/… $\endgroup$
    – rappolee
    Mar 19, 2016 at 14:37
  • $\begingroup$ ccar.colorado.edu/asen5050/projects/projects_2012/obrien/… Centaur made the initual injection aimpoint error as it has the avinoics for com/nav pasj.asj.or.jp/v63/n5/630537/630537-frame.html $\endgroup$
    – rappolee
    Mar 19, 2016 at 14:47
  • $\begingroup$ This is in answer to Puffin's third question;I googled the term "Departure from Jupiter Heliocentric Radial Component “ ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19690019063.pdf This paper discusses Jupiter flybys. Years later Ulysses that enters the in Heliocentric Radial Component and near Jupiter’s North pole bending Ulysses into a polar orbit around the sun. This trajectory by Jupiter is described here in figure 5 ccar.colorado.edu/asen5050/projects/projects_2012/reid So Jupiter B plane In near Jupiter's pole sends spacecraft “down” or South of the ecliptic $\endgroup$
    – rappolee
    Mar 19, 2016 at 15:45

Ultimately all probes will orbit Milky Way galaxy center as independent "artificial star systems". Take for example Voyager 1. It's speed relative to Sun is about $17 ~\text{km}/\text{s}$. Milky Way galaxy escape speed at Sun's position is about $550 ~\text{km}/\text{s}$. So Voyager 1 has reached only about $3\%$ of galaxy escape speed. Thus Voyager and all other probes (they moves slower than Voyager 1) will orbit Milky Way galaxy center as an artificial star systems forever. Unless some hazardous event to probe(s) happens (collision, etc.).


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