New Horizons vs Voyager: A Three-Way Comparison

NASA's Voyager 1, Voyager 2, and New Horizons are three of only five spacecraft ever placed on a trajectory that will eventually carry them out of the solar system. (The other two are Pioneers 10 and 11, both now silent.) Here's how they compare.

The "Fastest Spacecraft" Question

This trips people up because the answer depends on what you measure.

• Fastest at launch: New Horizons holds the record — it was launched at 16.3 km/s relative to Earth, faster than anything before or since.
• Fastest right now: Voyager 1, at about 17 km/s relative to the Sun, after gaining speed from gravity assists at Jupiter and Saturn.
• Fastest ever traveling away from the Sun: Voyager 1, again, because it was steered into a steep "escape" trajectory by Saturn's gravity.
• Fastest object in space (any kind): Neither — the Parker Solar Probe holds that record, hitting 192 km/s at perihelion. But Parker is in a tight orbit around the Sun, not heading anywhere.

Why Will Voyager 1 Stay Ahead?

New Horizons launched faster than Voyager 1 — but it didn't get any planetary gravity assists strong enough to compensate. Voyager 1 used Jupiter and Saturn each to add roughly 10–15 km/s. New Horizons got only a modest boost from Jupiter (about 4 km/s). Even though New Horizons launched 29 years later, it will never catch up to either Voyager. Voyager 1 will pass the heliopause's outer boundary first, second, and forever.

What Each Mission Uniquely Did

Voyager 1: First spacecraft to enter interstellar space (2012); only direct measurements of the interstellar medium's plasma density.

Voyager 2: Only spacecraft ever to visit Uranus or Neptune.

New Horizons: First (and only) spacecraft to fly past Pluto (2015), revealing nitrogen glaciers, towering ice mountains, and a hazy blue atmosphere. Then in 2019, it became the first spacecraft to closely observe a Kuiper Belt object beyond Pluto — Arrokoth, a peanut-shaped contact binary 6.6 billion km from Earth.