Parker Solar Probe and the Sun’s weather: flying through a star’s atmosphere

Drawn from 21 sources: NASA (13), NOAA Space Weather Prediction Center (3), The Planetary Society (2), NOAA NESDIS and 2 others. About 7 minutes. Checked October 1, 2026.

We live in the Sun’s atmosphere. A constant flow of material escapes the Sun as the solar wind and fills the entire solar system, and when gusts of it reach Earth they can set off auroras—but also expose astronauts to radiation, interfere with satellite electronics, and disrupt signals like GPS and radio.^1,3 NASA studies the Sun with a fleet of spacecraft at different distances. One of them, Parker Solar Probe, flies through the Sun’s outer atmosphere, the corona, closer to a star than anything built before it. On September 4, 2026, it made its 29th close pass.⁸

A mission conceived in 1958

In 1958, the University of Chicago physicist Eugene Parker developed a theory showing that the Sun’s corona—by then known to be millions of degrees—is so hot that it overcomes the Sun’s gravity, so that its material expands outward in all directions as a solar wind. A year later the Soviet spacecraft Luna 1 detected solar wind particles in space, and in 1962 NASA’s Mariner 2 confirmed it, finding a slow stream at about 215 miles per second and a fast one at twice that speed. In 1973, X-ray images from Skylab traced the fast wind to coronal holes, dark and comparatively cool regions on the Sun. When Parker Solar Probe launched, the origin of the slow wind was still a matter of decades-long, fierce debate.³

Seven Venus flybys to reach 3.8 million miles

A Delta IV Heavy launches Parker Solar Probe from Cape Canaveral, August 12, 2018.

NASA/Bill Ingalls

Parker Solar Probe was designed and built at the Johns Hopkins Applied Physics Laboratory, which operates it, and launched on August 12, 2018, on a Delta IV Heavy.¹ Getting close to the Sun means shedding the speed Earth gives everything launched from it, so the spacecraft used seven flybys of Venus to draw its orbit in. A few months after launch it was already the closest human-made object to the Sun and the fastest; on December 14, 2021, NASA announced that it had flown through the corona and sampled particles and magnetic fields there, the first spacecraft to touch the Sun.^1,2

The last Venus flyby, on November 6, 2024, put it in its final orbit: an oval that brings it close to the Sun every three months. On December 24, 2024, it passed 3.8 million miles above the surface at about 430,000 miles per hour, faster than any human-made object has ever moved. If the distance from the Sun to Earth were a football field, it would be four yards from the end zone. Out of contact during the pass, it sent a beacon tone on December 26 to say it was safe.⁴

1. Aug. 12, 2018

   Launch¹

   On a Delta IV Heavy from Cape Canaveral, with Eugene Parker watching.

2. Dec. 14, 2021

   First spacecraft to fly through the corona¹

   NASA announces Parker has sampled particles and magnetic fields inside the Sun’s upper atmosphere.

3. Nov. 6, 2024

   Seventh and last Venus flyby⁴

   Sets up the final orbit, which brings the spacecraft close to the Sun every three months.

4. Dec. 24, 2024

   Record pass: 3.8 million miles, 430,000 mph⁴

   The closest and fastest any spacecraft has flown; matched on every pass since.

5. Sept. 4, 2026

   29th close approach⁸

   Parker samples almost 40 percent of the Sun’s circumference in one day. Its mission is extended into 2029.

The spacecraft survives behind a carbon-composite shield 4.5 inches thick. It was designed to reach 2,600 degrees Fahrenheit—hot enough to melt steel—while keeping the instruments behind it at about room temperature; on the closest passes it reaches about 1,700 degrees. Autonomous software keeps the shield pointed at the Sun.^1,2,4,7 After nearly eight years and 28 passes, engineers reported in June 2026 that the shield was in excellent condition: the temperature behind it had not drifted upward, which is what they would see if it were cracking.⁷

What Parker sees inside the corona

Parker carries four instrument suites. FIELDS measures electric and magnetic fields with antennas that stick out past the heat shield into temperatures of 2,500 degrees Fahrenheit. SWEAP counts the most abundant particles in the solar wind—electrons, protons and helium ions—with a cup that peeks over the shield and glows red at 3,000 degrees. ISʘIS measures energetic particles across a wide range of energies. WISPR, the only camera, uses the heat shield to block the Sun’s glare and photographs the corona and solar wind before the spacecraft flies through them.⁵

When Parker first entered the solar atmosphere in 2021, it found the outer boundary of the corona wrinkled with spikes and valleys, contrary to what was expected. It traced zig-zag structures in the solar wind, called switchbacks, to the visible surface of the Sun, and it watched coronal mass ejections vacuum up dust as they swept across the solar system.⁴ Images from the December 2024 pass, released in July 2025, show the boundary where the Sun’s magnetic field direction switches from north to south, called the heliospheric current sheet, and capture for the first time in high resolution the collision of several coronal mass ejections. When those outbursts merge, their paths can change, which makes them harder to forecast at Earth.⁶

How the Sun’s storms reach Earth

Roughly every 11 years, at the height of its cycle, the Sun’s magnetic poles flip and it turns from calm to stormy. Sunspots, the visible parts of active regions with intense, tangled magnetic fields, are where solar eruptions start, so scientists count them to track the cycle. On October 15, 2024, NASA, NOAA and the international Solar Cycle Prediction Panel announced that the Sun had reached its solar maximum period.⁹

December 2019 · solar minimumMay 2024 · solar maximum

The largest geomagnetic storms come from coronal mass ejections, in which a billion tons or so of plasma, with its magnetic field, arrives at Earth. They usually take several days to cross, but the most intense have arrived in as little as 18 hours. When the solar wind’s magnetic field points south, opposite Earth’s, energy pours into the magnetosphere, driving intense electric currents high above the ground. Those currents heat the upper atmosphere, increasing drag on low satellites; they bend radio signals and introduce errors in GPS positions; and they induce currents in power lines and pipelines.¹¹

Currents induced in the grid can push power transformers out of their designed range and saturate their cores, heating them and tripping protective equipment elsewhere on the network. NOAA lists a nine-hour blackout in Canada and a transformer loss on March 13, 1989, and a blackout in Sweden during the October 2003 storm.¹² In orbit, the March 1989 storm thickened the upper atmosphere so suddenly that NASA’s Solar Maximum Mission satellite was reported to have “dropped as if it hit a brick wall,” and after big storms the North American Aerospace Defense Command has to re-identify hundreds of objects whose orbits have changed.¹³

Warnings from a million miles out

Forecasters get their warning from a point about a million miles toward the Sun, the first Lagrange point, L1, where spacecraft see solar storms coming before they arrive. NASA’s IMAP, which launched on September 24, 2025, and traveled to L1 together with the Carruthers Geocorona Observatory and NOAA’s Space Weather Follow On-Lagrange 1, entered its final orbit there on January 10, 2026, joining NASA’s Wind and ACE and the ESA–NASA SOHO. Its primary job is to map the boundary of the heliosphere, but since February 1, 2026, part of its data has also streamed to forecasters in near real time, giving astronauts and spacecraft near Earth about half an hour’s warning of harmful radiation.^15,16

30 min

for SOLAR-1’s images of a coronal mass ejection to reach forecasters, against up to 8 hours from SOHO¹⁴

5 min

for SOLAR-1’s solar wind measurements to arrive¹⁴

~30 min

of warning IMAP’s real-time data give spacecraft near Earth¹⁵

NOAA’s satellite, renamed SOLAR-1 when it reached L1, is the first NOAA satellite designed specifically for continuous, operational space weather observation. Its compact coronagraph puts images of coronal mass ejections in forecasters’ hands within 30 minutes, compared with up to eight hours from research instruments such as SOHO’s coronagraph, and its solar wind measurements arrive within five minutes.¹⁴

A 52 percent cut proposed for heliophysics

For 2026 the administration proposed cutting NASA’s Heliophysics Division roughly in half. Congress instead gave it $874.8 million, including $25 million to operate Parker against a request of $15 million, and kept the Geospace Dynamics Constellation and HelioSwarm missions the administration had proposed to cancel.¹⁷

NASA heliophysics funding¹⁹

Show the numbers

year	Heliophysics
2025 enacted	$792M
2026 enacted	$875M
2027 request	$420M

The 2027 request returns to the same idea: $419.6 million for heliophysics, a 52 percent cut from 2026. It keeps $101 million to operate IMAP and Parker and $73 million for space weather research, but The Planetary Society counted 17 heliophysics missions with a combined lifetime cost of about $2.8 billion that would end.^18,19,20 Congress had not passed a 2027 bill when the fiscal year began; a continuing resolution holds NASA at its 2026 level through December 11.²¹

Parker, meanwhile, will stay in its current orbit. A 2026 senior review of heliophysics missions extended it into 2029, long enough to follow the Sun from the quiet minimum at its launch, through the maximum, into the declining phase—when, scientists note, fairly significant storms still occur.^8,9