Parker Solar Probe launch
On 12 August 2018 the Parker Solar Probe launched to fly through the Sun’s corona and sample the solar wind — the first NASA spacecraft named after a living person.
Available views: Orbit ✓ · Sky — (not visible in the sky)
The story
On 12 August 2018 the Parker Solar Probe lifted off from Florida on a Delta IV Heavy rocket. At the launch site was the 91-year-old physicist Eugene Parker. In 1958 he had proposed the solar wind, the idea that charged particles stream out of the Sun without stopping, like a wind. Many scientists doubted him at first, but observations proved him right a few years later. It was the first time NASA had named a spacecraft after a living person.
Flying to the Sun is harder than it sounds. Earth circles the Sun at about 30 km/s, and a spacecraft launched from Earth starts out with that same sideways speed. To fall toward the Sun, it has to lose most of that speed. So between 2018 and 2024 Parker flew past Venus seven times, using the planet’s gravity like a brake to slow down a little each time.
In April 2021 the probe entered the corona, the Sun’s outer atmosphere, for the first time. On 24 December 2024 it came within about 6.1 million km of the Sun’s surface, only about one twenty-fifth of the distance between the Sun and Earth. It was moving at about 690,000 km/h, fast enough to fly from London to New York (about 5,570 km) in about half a minute. A carbon shield about 11 cm thick took heat of nearly 1,370 °C on its front, keeping the instruments behind it near room temperature.
The probe now circles the Sun about every 88 days, returning to the same close distance each time. With no Venus flybys left, its orbit will not shrink any further. Eugene Parker saw the spacecraft send back data from near the Sun before he died in 2022 at the age of 94. The orbit view replays how the orbit tightened toward the Sun at each pass of Venus.
Mission goals
Parker is the first spacecraft to go right into the region where the solar wind forms and speeds up. The Sun’s surface is about 5,500 °C, yet the corona above it reaches millions of degrees. It is as if the air grew hotter the farther one moved from a fire, and this puzzle has stood for decades. Near the Sun the probe found many “switchbacks”, places where the magnetic field suddenly flips direction, and scientists think these may be a clue to how the corona is heated.
The solar wind also touches daily life on Earth. When a big eruption on the Sun sends a strong blast of solar wind our way, satellites can fail and power grids and communications can be disturbed. This is called space weather. Knowing how solar storms begin in the corona could make space-weather forecasts more accurate, much as better data improves ordinary weather forecasts.
Using Venus as a brake is worth noting too. Flying past a planet is usually a way to gain speed, but for a spacecraft heading toward the Sun it is a way to lose speed. MESSENGER and BepiColombo, both bound for Mercury, and Solar Orbiter, which circles the Sun, used similar tricks and saved large amounts of fuel.
Mission chronology and background
The idea of sending a probe close to the Sun was first raised in 1958. But nobody could yet build a shield able to survive the heat, so the plan had to wait nearly sixty years. Only after light, heat-resistant carbon composite materials were developed did the mission become possible. It was first called Solar Probe Plus and was renamed after Parker in May 2017.
The spacecraft carries a memory card holding the names of more than 1.1 million people, along with photos of Eugene Parker and a copy of his 1958 paper on the solar wind. Its primary mission ended in 2025, and an extended mission through 2029 was approved, so it keeps swinging close to the Sun.
Most instruments hide in the shield’s shadow, but one, the Solar Probe Cup, sticks out past the shield to catch solar-wind particles in direct sunlight. It is built from special metals and sapphire to survive temperatures above 1,600 °C. One day the fuel will run out and the probe will no longer keep its shield pointed at the Sun. The instruments will then be ruined by the heat, but the shield itself is expected to keep circling the Sun for millions of years.
Other milestones of this mission
Where to see it — sky and simulator
The Parker Solar Probe always stays close to the Sun, so it cannot be seen from the ground. Select it in the orbit view to see its current position, calculated from orbital data, and its track over the last 90 days, grazing the Sun every 88 days inside the orbit of Venus. Speed up the playback to follow its orbit shrinking step by step, from the 2018 launch through seven Venus flybys to its closest approach in December 2024.
Select the Sun in the sky view to see its height and direction from your location and today’s sunrise and sunset times. Never look at the Sun directly with the naked eye or through a telescope, as this can badly damage the eyes; any solar viewing needs a proper solar filter. Stacked sunglasses do not protect the eyes; only certified filters such as eclipse glasses do.
See this for yourself — replay the moment in the orbit view
FAQ
How close did it get to the Sun?
On 24 December 2024 it came within about 6.1 million km of the Sun’s surface, roughly one twenty-fifth of the Sun–Earth distance.
Why did it fly past Venus seven times?
It had to lose the sideways speed it inherited from Earth before it could fall toward the Sun, and Venus’s gravity acted as a brake.
Why doesn’t it melt?
A carbon shield about 11 cm thick blocks heat of nearly 1,370 °C, keeping the instruments behind it near room temperature. The corona is hot but so thin that it passes on less heat than one might expect.
Why was it named after a living person?
To honour Eugene Parker, who predicted the solar wind in 1958. It was a first for a NASA spacecraft; Parker died in 2022.
Related
- BepiColombo launch — to Mercury
- Mariner 2 — first planetary probe
- Total solar eclipse of August 2027
- Parker Solar Probe — object index
- The Sun — object index
Times and figures are approximate — verify with official sources when planning travel. Simulation uses J2000 mean elements.