Parker Solar Probe

Parker Solar Probe
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Name	Parker Solar Probe
Mission type	Heliophysics
Operator	NASA / Johns Hopkins University Applied Physics Laboratory
Website	https://www.nasa.gov/parker
Mission duration	7 years (planned), Elapsed: August 12, 2018
Manufacturer	Johns Hopkins University Applied Physics Laboratory
Launch mass	685 kg
Power	343 W (at closest approach)
Launch date	August 12, 2018, 07:31 UTC
Launch rocket	Delta IV Heavy / Star-48BV third stage
Launch site	Cape Canaveral SLC-37

Parker Solar Probe is a NASA robotic spacecraft launched in 2018 to perform unprecedented close observations of the outer atmosphere of the Sun. The mission, developed and operated by the Johns Hopkins University Applied Physics Laboratory, is designed to trace the flow of energy, understand the heating of the solar corona, and explore the mechanisms that accelerate the solar wind. It is the first spacecraft to be named for a living person, honoring astrophysicist Eugene Parker.

Overview

The mission represents a landmark in heliophysics, aiming to answer fundamental questions about stellar physics that have persisted for decades. By venturing closer to the Sun than any previous spacecraft, it endures extreme heat and radiation to gather data from within the solar corona. The project builds upon earlier solar missions like Helios and SOHO, but with vastly improved technology to survive the harsh environment. International collaboration includes contributions from institutions like the University of California, Berkeley and the Smithsonian Astrophysical Observatory.

Mission objectives

Primary scientific goals are to determine the structure and dynamics of the magnetic fields at the sources of the solar wind, trace the flow of energy that heats the corona and accelerates the wind, and explore the mechanisms that accelerate and transport energetic particles. A key objective is to understand why the solar corona is millions of degrees hotter than the Sun's visible surface, a puzzle known as the coronal heating problem. The mission also seeks to characterize the plasma and dust environment near the Sun to improve space weather forecasting for Earth.

Spacecraft design

The spacecraft's design is dominated by a revolutionary thermal protection system, a 4.5-inch-thick carbon-composite shield that withstands temperatures exceeding 1,370 °C. The majority of the probe's instruments are located in the shadow of this heat shield, which is autonomously aligned to protect the payload from direct solar irradiation. The structure uses a carbon foam core and is coated with a white ceramic layer. Power is provided by two solar arrays that retract and extend to manage thermal load, with a sophisticated active cooling system using circulated water.

Scientific instruments

The probe carries four major instrument suites. The FIELDS experiment, led by the University of California, Berkeley, measures electric and magnetic fields and radio waves. The Integrated Science Investigation of the Sun (ISʘIS), led by Princeton University and the University of New Hampshire, characterizes energetic particles. The Wide-field Imager for Solar Probe (WISPR), led by the Naval Research Laboratory, provides visible-light imaging of the corona and solar wind. The Solar Wind Electrons Alphas and Protons (SWEAP) investigation, led by the Smithsonian Astrophysical Observatory and the University of Michigan, directly counts and measures particles in the solar wind.

Mission profile and timeline

Launched atop a Delta IV Heavy rocket from Cape Canaveral Space Force Station in August 2018, the spacecraft utilizes a series of seven gravity assist maneuvers at Venus over nearly seven years to gradually shrink its orbit. Each flyby at Venus lowers the probe's perihelion, bringing it progressively closer to the Sun. The final orbits will reach within 6.2 million kilometers of the Sun's surface, far inside the orbit of Mercury. The primary mission is scheduled to conclude in 2025, having completed 24 planned close approaches.

Discoveries and findings

Early data has revolutionized understanding of the near-Sun environment. The probe discovered switchback structures in the solar wind—sudden, localized reversals in the magnetic field—suggesting they originate from processes on the Sun's surface. It provided the first direct evidence of a dust-free zone near the Sun and characterized the highly dynamic plasma conditions in the inner heliosphere. Observations have also detailed the structure of the solar corona and the acceleration of particles from small solar flare events, providing critical data for models developed by institutions like the National Center for Atmospheric Research.

Category:NASA probes Category:Solar spacecraft Category:Johns Hopkins University Applied Physics Laboratory Category:Spacecraft launched in 2018