Top 5 Fastest Spacecrafts Ever Built [With Speed in km/s]

Speed is one of the most crucial aspects of space exploration. Whether it’s escaping Earth’s gravity, reaching distant planets, or studying the Sun, spacecraft must travel at incredible velocities. Over the years, several space agencies have built record-breaking spacecrafts, each pushing the boundaries of speed and engineering.

In this article, we’ll look at the top 5 fastest spacecrafts ever built as of 2025, measured by their maximum recorded speed in kilometers per second (km/s).

1. Parker Solar Probe –192 km/s (Fastest Ever)

• Agency: NASA (United States)
• Launched: August 12, 2018
• Mission Goal: Study the outer corona of the Sun
• Top Speed: 192 km/s (as of 2025, projected to reach 200+ km/s in future flybys)

Why it’s fastest: The Parker Solar Probe holds the current record for the fastest human-made object. It achieved this speed by using multiple gravity assists from Venus and diving extremely close to the Sun — closer than any spacecraft in history.

2. Helios 2 – 70.2 km/s

• Agency: NASA / DLR (Germany)
• Launched: January 15, 1976
• Mission Goal: Study solar wind and solar magnetic fields
• Top Speed: 70.2 km/s

Why it’s special:
Helios 2 was part of a mission to study the inner solar system and came within 43 million km of the Sun. It held the fastest speed record for decades before being overtaken by Parker Solar Probe.

3. Helios 1 – 66 km/s

• Agency: NASA / DLR (Germany)

• Launched: December 10, 1974

• Mission Goal: Solar studies in collaboration with Helios 2

• Top Speed: 66 km/s

Why it’s fast: Helios 1 was the forerunner to Helios 2 and had a similar trajectory. Both spacecrafts provided key early data about the Sun’s atmosphere and paved the way for modern solar missions.

4. New Horizons – 16.3 km/s

• Agency: NASA
• Launched: January 19, 2006
• Mission Goal: Flyby of Pluto and exploration of the Kuiper Belt
• Top Speed: 16.3 km/s (at launch, one of the fastest ever)

Why it’s famous: New Horizons was the first spacecraft to explore Pluto, delivering stunning images and data in 2015. It continues to explore the Kuiper Belt and remains one of the fastest spacecrafts still operational.

5. Voyager 1 – 17 km/s (Relative to the Sun)

• Agency: NASA
• Launched: September 5, 1977
• Mission Goal: Explore outer planets; now in interstellar space
• Top Speed: 17 km/s

Why it’s legendary: Voyager 1 is the farthest human-made object from Earth, currently traveling in interstellar space. Though not the fastest at launch, gravity assists from Jupiter and Saturn accelerated it to incredible speeds.

Comparison Table: Fastest Spacecrafts (2025)

Why Are These Speeds Important?

• Escape Velocity: To leave Earth’s gravity, a spacecraft needs to reach at least 11.2 km/s.
• Solar Missions: Require much higher speeds to counter the Sun’s gravitational pull.
• Interplanetary and Interstellar Travel: The faster the spacecraft, the more ground it can cover in space exploration.