Parker Solar Probe: Humanity’s First Visit to a Star

NASA’s Parker Solar Probe is transforming our understanding of the Sun and how its changing conditions impact the solar system, including Earth and other planets. This mission takes the spacecraft through the Sun’s outer atmosphere, closer to its surface than any previous spacecraft, enduring extreme heat and radiation to provide the closest observations of a star ever recorded.

Journey to the Sun

• Launch Date: August 12, 2018
• Launch Location: Cape Canaveral Air Force Station, Florida
• Launch Vehicle: Delta IV-Heavy with Upper Stage

To explore the mysteries of the Sun’s atmosphere, Parker Solar Probe relies on Venus’ gravity during seven flybys over nearly seven years. These maneuvers gradually bring its orbit closer to the Sun. The spacecraft is designed to reach within 3.8 million miles of the Sun’s surface, traveling well inside Mercury’s orbit. For comparison, Earth orbits the Sun at an average distance of 93 million miles.

Flying into the corona, the Sun’s outermost atmosphere, Parker Solar Probe collects data through direct measurements and imaging. This mission is reshaping our knowledge of the corona and the solar wind’s origins and behavior. The findings from this probe will also enhance our ability to predict space weather, which can impact technology and life on Earth.

Extreme Exploration

At its closest approach, the Parker Solar Probe travels around the Sun at an astonishing speed of approximately 430,000 mph (700,000 kph). At that velocity, it could cover the distance between Philadelphia and Washington, D.C., in just one second.

As it nears the Sun, the spacecraft's solar shield endures extreme temperatures reaching about 2,500°F (1,377°C), yet its internal instruments remain near room temperature. During its final three orbits, Parker Solar Probe will come as close as 3.8 million miles to the Sun’s surface. This is more than seven times closer than the previous record set by the Helios 2 spacecraft, which reached 27 million miles from the Sun in 1976. It is also about one-tenth the distance of Mercury, which orbits the Sun at an average of 36 million miles.

Operating in one of the most extreme environments in the solar system, Parker Solar Probe flies through a region filled with intense heat and solar radiation. The mission allows scientists to observe the acceleration of the solar wind as it shifts from subsonic to supersonic speeds and provides a rare opportunity to study the birthplace of the highest-energy solar particles. To withstand such harsh conditions, the spacecraft is equipped with a 4.5-inch-thick (11.43 cm) carbon-composite heat shield, designed to protect its instruments from external temperatures nearing 2,500°F (1,377°C), ensuring it can continue collecting critical scientific data.

The Science of the Sun

The main scientific objectives of the mission are to understand how energy and heat move through the solar corona and to determine what drives the acceleration of the solar wind and energetic solar particles. Researchers have been searching for these answers for over 60 years, but solving these mysteries requires a probe to travel directly through the corona’s extreme heat of 2,500 degrees Fahrenheit. Thanks to advanced thermal engineering, this mission is now possible, allowing the spacecraft to withstand the harsh conditions of its journey.

Parker Solar Probe is equipped with four instrument suites specifically designed to analyze magnetic fields, study plasma and energetic particles, and capture images of the solar wind. These tools will provide critical data to help scientists better understand the Sun’s activity and its effects on the solar system.

Teaming for Success

Parker Solar Probe is part of NASA’s Living With a Star program, which focuses on studying the Sun-Earth system and its impact on life and society. The Living With a Star flight program is managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, under the Science Mission Directorate in Washington. The Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland, oversees the mission for NASA. APL also designed, built, and currently operates the spacecraft.

Why Do We Study the Sun and the Solar Wind?

• The Sun is the only star that can be observed closely, providing valuable insights into how stars function across the universe.
• Understanding the Sun, Earth’s main source of light and heat, helps scientists learn more about how life developed and continues to evolve.
• The Sun produces the solar wind, a continuous stream of charged particles traveling past Earth at speeds exceeding 500 km per second (about a million miles per hour).
• Solar wind disturbances can impact Earth’s magnetic field, create space weather events, and affect radiation belts, potentially disrupting satellites and onboard electronics.
• Since the solar wind influences much of the solar system, studying it is essential for ensuring the safety of spacecraft and astronauts as they travel beyond Earth’s orbit.