NASA’s Parker Solar Probe is once again venturing into uncharted territory, making its closest approach yet to the Sun’s surface. On March 22, the spacecraft swooped within just 3.8 million miles (6.1 million kilometers) of the Sun’s surface, traveling at a staggering speed of 430,000 miles per hour (692,000 km/h). This marks the probe’s 23rd close encounter, offering another opportunity to gather groundbreaking data on the Sun’s corona and the solar wind.
This latest approach, confirmed by NASA on March 21, continues the mission’s quest to unlock the secrets of the Sun’s outer atmosphere. With each dive into the corona—the superheated outer layer that extends millions of miles into space—the probe helps scientists understand why this region is significantly hotter than the Sun’s surface and how solar winds accelerate to such high speeds.
Pushing the Boundaries of Solar Exploration
Parker Solar Probe first made history in December 2024 when it completed the closest-ever flyby of the Sun. Now, it has repeated the feat, once again venturing into the corona, where temperatures soar to millions of degrees Fahrenheit.
During these encounters, the spacecraft operates completely autonomously, as intense radiation and plasma conditions make real-time communication with Earth impossible. Mission control at Johns Hopkins Applied Physics Laboratory last received a signal from Parker on March 16 and expects to regain contact on March 25, once the flyby is complete.
Despite enduring one of the most extreme environments in the solar system, the probe remains fully operational, continuing its mission to gather unprecedented data on the Sun’s behavior.
Unraveling the Mysteries of the Sun
Each flyby brings new insights into solar physics. Among the primary objectives of the Parker Solar Probe mission is to answer two fundamental questions:
1. Why is the corona hotter than the Sun’s surface? While the Sun’s surface, or photosphere, is about 10,000°F (5,500°C), the corona reaches temperatures of several million degrees—an ongoing mystery in astrophysics.
2. How do solar winds accelerate to immense speeds? These charged particles, constantly streaming from the Sun, impact space weather and influence conditions on Earth. Understanding their origins could help improve space weather predictions, protecting satellites and power grids from solar storms.
The probe is equipped with four advanced instruments designed to study magnetic fields, high-energy particles, and plasma waves within the corona. The data collected during previous flybys has already provided valuable insights into solar wind formation, and this new approach is expected to refine those findings.
Engineering Marvel: Built to Survive the Sun
Surviving so close to the Sun requires exceptional engineering. The Parker Solar Probe is protected by a 4.5-inch-thick (11.4 cm) carbon-composite heat shield, which withstands temperatures up to 2,500°F (1,377°C). Despite the intense heat outside, the spacecraft’s internal instruments remain at near-room temperature, allowing precise data collection.
Perhaps even more remarkable is Parker’s ability to navigate independently. With no real-time commands from Earth, it must autonomously adjust its trajectory, stabilize its sensors, and ensure its heat shield remains perfectly aligned—all while traveling at speeds nearly seven times faster than a space shuttle.
A Mission Like No Other
As the Sun approaches its solar maximum—the peak of its 11-year activity cycle—these close approaches become even more valuable. The increased solar activity will provide researchers with even more dynamic data on solar flares, magnetic field interactions, and space weather phenomena.
With several more close flybys scheduled before the mission concludes, Parker Solar Probe continues to push the boundaries of human understanding, providing an unprecedented glimpse into the heart of our solar system.
