Parker Solar Probe launch

The mission to "touch the Sun" — and the first NASA craft named for a living scientist.

The moment of Parker Solar Probe launch: https://nowsky.org/e/parker-launch — opens at the right place and time, replayable, no login.

Available views: Orbit ✓ · Sky — (not visible in the sky)

The story

On 12 August 2018 the Parker Solar Probe left on a Delta IV Heavy. Eugene Parker, aged 91, watched the launch — the physicist who had predicted the solar wind in 1958 and been ridiculed for it. It was the first time NASA had named a spacecraft after a living person.

Going to the Sun is, paradoxically, the hardest flight in the solar system. Earth's orbital speed of 30 km/s has to be cancelled before anything can fall sunward, so the trajectory used seven Venus flybys over seven years to shed speed. Gravity assists usually add velocity; Parker used Venus as a brake.

It entered the corona in April 2021, and on 24 December 2024 it came within 6.1 million km of the surface — 8.8 solar radii — passing at 192 km/s, the fastest and closest any human-made object has flown. An 11 cm carbon shield held off 1,400 °C while the instruments behind it stayed at room temperature.

Parker now repeats the same perihelion every 88 days — no further Venus flybys are planned, so the orbit tightens no more. The orbit view replays the spiral drawing ever closer to the Sun. Watching the launch, Parker said, "now we go to touch it"; he died in 2022 at 94.

Why it matters

Parker is the first spacecraft to measure on site where the solar wind is accelerated. To the sixty-year-old coronal heating problem — why the corona is hundreds of times hotter than the surface — it contributed part of an answer by discovering "switchbacks", sudden reversals of the magnetic field. What had only been inferred from Earth was touched from inside.

Using Venus flybys as brakes was a change of thinking in navigation. The method was reused by BepiColombo (to Mercury, 2018) and Solar Orbiter (2021) and has become standard for inner-solar-system missions.

The solar wind is the source of space weather that threatens satellites, power grids and communications. Parker's data show how solar storms begin in the corona before they reach Earth, the foundation for more accurate space-weather forecasts.

How to watch

Parker is too close to the Sun to be seen from the ground. Select it in the orbit view for its current position from measured orbital elements and its track over the last 90 days, grazing the Sun every 88 days inside the orbit of Venus.

The orbit replay runs from the August 2018 launch through seven Venus flybys to the closest approach of December 2024; at high speed the perihelion can be seen pulled inward at each Venus pass.

Select the Sun in the sky view for its altitude, bearing, today's sunrise and sunset and its 24-hour track from your location; with the daytime sky on, the glare around the Sun gives a sense of where the corona lies.

See this for yourself — replay the moment in the orbit view

Background

A close solar probe was proposed as early as 1958 but waited sixty years for heat-shield technology. Carbon–carbon composite shields became practical only in the 2000s, and the mission, originally "Solar Probe Plus", was renamed for Parker in 2017.

Aboard is Parker's 1958 paper, his photograph and a memory card with 1.1 million names. After the launch Parker discussed the first results with the team as the data came down.

Since 2025 Parker has repeated its perihelion passes, observing the corona of solar maximum (2024–2026) from within. The mission continues as long as propellant lasts; when attitude control is eventually lost the shield will no longer face the Sun and the probe will melt away.

All four of Parker’s instrument suites sit in the shadow of the heat shield; only one cup, which samples solar-wind particles, protrudes past it into direct sunlight. This Solar Probe Cup, made of molybdenum alloy and sapphire, withstands 1,600 °C while measuring the wind’s speed, density and temperature directly. The spacecraft’s attitude is held second by second by sun sensors watching for light leaking past the shield’s edge; losing attitude would melt the instruments within minutes, so autonomous control is the mission’s core technology.

FAQ

How close did it get to the Sun?

Within 6.1 million km of the surface — 8.8 solar radii — on 24 December 2024.

Why seven Venus flybys?

To shed Earth's orbital speed and fall toward the Sun — Venus served as a brake.

Why does it not melt?

An 11 cm carbon shield holds off 1,400 °C while instruments behind it stay at room temperature; the corona is hot but so thin that little heat is transferred.

Why name it after a living person?

To honour Eugene Parker, who predicted the solar wind in 1958 — a first for a NASA spacecraft; Parker died in 2022.

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Times and figures are approximate — verify with official sources when planning travel. Simulation uses J2000 mean elements.