Parker Solar Probe

Key facts

Mission & specifications

Mission

Parker Solar Probe is the first spacecraft to fly into the Sun's atmosphere — the mission that, as NASA puts it, 'touched the Sun'. Launched on 12 August 2018, it set out to answer questions older than spaceflight: why the Sun's outer atmosphere, the corona, is hundreds of times hotter than its visible surface, and what accelerates the solar wind that streams across the Solar System. To get close it does something counter-intuitive, using seven gravity-assist flybys of Venus to slow down and drop its orbit ever nearer the Sun. A revolutionary carbon-composite heat shield, enduring temperatures over 1,300 degrees Celsius, keeps the instruments behind it near room temperature. In 2021 the probe flew through the corona for the first time, sampling the magnetic structures within it, and on 24 December 2024 it made its closest approach yet, skimming just 6.1 million kilometres above the surface at about 690,000 kilometres per hour — making Parker the fastest object humans have ever built. Its measurements have revealed strange zigzag reversals in the Sun's magnetic field, nicknamed 'switchbacks', and are helping explain how the solar wind is born. The mission is named after the physicist Eugene Parker, who predicted the solar wind in 1958 — the first NASA spacecraft ever named after a living person, an honour he lived to see launched.

1. 2018Launch toward the SunLaunch

   A Delta IV Heavy sends Parker on a mission to fly through the Sun's atmosphere.

2. 2018First Venus gravity assistFlyby

   The first of seven Venus flybys begins lowering the orbit ever closer to the Sun.

3. 2021First passage through the coronaMilestone

   Parker becomes the first spacecraft to fly inside the Sun's outer atmosphere.

4. 2024Closest approach — and fastest everMilestone

   Skimming 6.1 million km above the surface at ~690,000 km/h, the fastest object humans have built.

Images

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