6. Helios 2 – Fastest Human-Made Spacecraft (Relative to the Sun)
Launched in the 1970s, NASA and Germany’s Helios 2 remains the fastest human-made object relative to the Sun, reaching speeds of 157,078 mph (252,792 km/h). It was built to study the solar environment, including solar wind and magnetic fields.
Helios 2 had to be incredibly heat-resistant, as it flew closer to the Sun than Mercury. Special heat shields were necessary to withstand the intense solar radiation and high temperatures during its orbit.
It provided valuable data about solar flares and coronal mass ejections — phenomena that affect satellites, communication systems, and power grids on Earth. Though it’s no longer active, Helios 2’s mission was groundbreaking in both science and speed.
Even decades later, few spacecraft have approached its speed. Its record stood until the next entry on this list came into play — a mission that brought us even closer to the Sun.
