Pioneer 10
What is Pioneer 10?
Probes & telescopes· Launched 1972-03-02 – contact lost 2003-01-23 (drifting outward in silence). The pathfinder that first crossed the asteroid belt and first flew past Jupiter. Launched in 1972, it measured Jupiter's radiation belts in 1973 and, silent since 2003, still coasts toward Aldebaran at 12 km/s carrying a plaque for whoever finds it.
The orbit of Pioneer 10 at this moment: https://nowsky.org/solar/orbit?fw=probe%3Apioneer10 — replayed live, no login.
Mission timeline
Spacecraft specs
| Launch | 1972-03-02 |
|---|---|
| Jupiter flyby | 1973-12-03 |
| Last contact | 2003-01-23 |
| Distance now | ~142 AU (as of Sept 2026), toward Aldebaran |
Figures are representative approximations. Distances that change over time are extrapolated from 2020-01-01. Source: compiled from NASA and IAU public data.
Frequently asked
- When did Pioneer 10 launch?
- 1972-03-02.
- How far is Pioneer 10 from Earth?
- ~142 AU (as of Sept 2026), toward Aldebaran.
- In one line, what is Pioneer 10?
- Probes & telescopes — The pathfinder that first crossed the asteroid belt and first flew past Jupiter.
Two million years to Aldebaran — which will not be there
Pioneer 10 is heading toward Aldebaran in Taurus, and at its present speed the 65 light-years would take about two million years. But stars move too. Aldebaran travels at 54 km/s relative to the Sun, so by the time the probe arrives the star will have shifted light-years from where it is now. "Toward Aldebaran" describes the direction of departure, nothing more; the trajectory passes close to no star at all.
The same is true of the Voyagers and New Horizons. The space between stars is so empty that none of humanity's five interstellar probes will enter another star's Oort cloud within tens of thousands of years. That is why the odds of Pioneer 10's plaque ever being read are effectively zero — and why attaching it was not a bet on "perhaps" but a record of "this is what we were".
The mission in depth
Pioneer 10 was NASA's trailblazer to the outer solar system, launched on 2 March 1972 on an Atlas-Centaur. It was the fastest spacecraft ever flown at the time, and that July it entered the asteroid belt and crossed it unharmed — the first proof that the belt was not a lethal barrier. Without that result the Voyager missions would have been a much harder sell.
On 3 December 1973 it passed 130,000 km above Jupiter's cloud tops, photographing the Great Red Spot and the moons up close and making the first measurements of the planet's ferocious radiation belts and vast magnetosphere. Jupiter's gravity flung it onto a solar-system-escape trajectory; it crossed Neptune's orbit in 1983 as the most distant human object (Voyager 1 overtook it in 1998) and sent its last faint signal on 23 January 2003 from about 82 AU, its plutonium power exhausted.
Bolted to the frame is a gold-anodised aluminium plaque showing a man and a woman and the Sun's position in the Galaxy. Now (as of 2026) about 142 AU out, it drifts toward Aldebaran in Taurus at 12 km/s and will take roughly two million years to pass near that star. Track Pioneer 10 in the orbit view to watch its path straighten into a hyperbola after the Jupiter flyby.
Related
Figures are representative approximations. Simulated positions use J2000 mean elements.