Missions · Space Codex
Parker Solar Probe
Parker flies through the Sun's outer atmosphere at up to 692,000 km/h, closer than any spacecraft before it.
The fastest human-made object
At a glance
Key points
- Fastest human-made object
- 6.1 million km from the Sun's surface
- Extended into 2029
About this view
On the Sun destination the probe is drawn from the NASA 3D Resources model, enlarged and closer to the Sun than its real perihelion (9.86 solar radii from the centre), with its heat shield turned to the Sun.
Touching the corona
Inside the corona the spacecraft samples the plasma that becomes the solar wind, testing ideas about why the corona is hundreds of times hotter than the surface below.
Using Venus as a brake
Leaving Earth, a spacecraft carries Earth's orbital speed of about 30 km/s sideways to the Sun, and that sideways motion must be shed before it can fall close. Even a Delta IV Heavy could not do that in one go. Parker instead passed Venus seven times between 2018 and 2024, each pass trimming its orbit so the next perihelion came deeper. The final flyby, on 6 November 2024, set up the record pass seven weeks later.
Crossing the Alfvén surface
The corona has an outer edge of sorts: the Alfvén critical surface, where the solar wind starts moving faster than magnetic waves can travel back toward the Sun. Below it, plasma is still tied to the Sun's magnetic field. Parker first dipped beneath it on 28 April 2021, at 18.8 solar radii, and has crossed it repeatedly since. The boundary turned out to be wrinkled with spikes and valleys rather than smooth.
Alone at closest approach
Around each perihelion Parker flies on its own for about nine days, out of contact by design, keeping its shield pointed at the Sun and running its instruments autonomously. A beacon tone afterwards tells the team it came through; the science data follows over the next weeks. Behind the shield, the instruments stay near room temperature while the Sun-facing side heats to nearly 1,000 °C.
The extended mission
The original plan was 24 orbits over seven years. Parker now holds a fixed orbit of about 88 days, Mercury's year, with a perihelion every three months at the same 6.1 million km. The 2026 Heliophysics Senior Review extended it into 2029, so it will sample the solar wind as the Sun winds down from the maximum of solar cycle 25 into the quieter years that follow.
What we still don't know
Exactly which mechanism, waves or tiny magnetic explosions, heats the corona to millions of degrees.
Missions
- 2018–
Parker Solar Probe
NASAActiveClosest pass 24 Dec 2024 (6.1 million km); extended into 2029.
First-hand · our 3D model
How we render it
Parker Solar Probe appears in the Sun view on Explore, at the full quality setting only. It makes an illustrative slow pass through the corona with its heat shield always turned to the Sun, on an arc tipped towards you so it crosses beside the limb rather than hiding behind the disc. Neither distance nor size is to scale: the pass is at 1.3 solar radii from the Sun's centre, against a real closest approach of 9.86, and the probe is drawn at 14% of the Sun's radius.
The model is from NASA 3D Resources, loaded on demand as a Draco-compressed file and released when you leave the destination. It carries no NASA insignia, and its use implies no endorsement. The scene has no environment map for metal to reflect, so metalness is capped to keep metal parts from reading black.
Related entries
- The SunG2V main-sequence star · 4.6 billion years old
Sources
- NASA Science: Parker's closest pass to the Sun (opens in a new tab)
- NASA Science: Parker Solar Probe blog, Sep 2026 (opens in a new tab)
- NASA Science: Parker Solar Probe (opens in a new tab)
- NASA Science: Final Venus flyby queues closest Sun pass (opens in a new tab)
- NASA: Enters the solar atmosphere for the first time (opens in a new tab)
Last reviewed against these sources. Built from public NASA, ESA and JPL data; not affiliated with or endorsed by any agency.