Parker Solar Probe

Parker Solar Probe studies the corona, the Sun's extended outer atmosphere, and the solar wind, the stream of charged particles flowing outward from the Sun. The mission addresses questions such as how the corona is heated to temperatures far above the visible solar surface and how the solar wind is accelerated. Its measurements are taken in situ, meaning the spacecraft directly samples plasma, energetic particles and magnetic fields as it travels through the solar environment.

Launched on 12 August 2018, the probe uses repeated close solar passes rather than a single descent. Its highly elliptical orbit brings it progressively near the Sun, with gravity assists from Venus helping reshape the orbit. At closest approaches, a carbon-composite heat shield keeps the spacecraft and instruments in a protected region while the shield's sun-facing side endures extreme heating. The design allows the spacecraft to collect measurements at distances from the Sun that other operating spacecraft have not reached.

In April 2021, Parker Solar Probe crossed into the corona, a milestone NASA announced in December of that year. The crossing was identified using measurements of the solar environment, including changes in magnetic fields and particles that marked passage through the Alfvén critical surface. The boundary is not a solid shell: its shape and position vary with solar conditions. Sampling the corona helps scientists connect processes near the Sun to the solar wind observed farther away.

NASA manages the mission through its Goddard Space Flight Center, with spacecraft development and operations led by Johns Hopkins Applied Physics Laboratory. Four instrument suites measure magnetic and electric fields, plasma and energetic particles, and image the solar wind and corona. The resulting observations help improve understanding of space weather, which can affect satellites, communications, navigation systems and other technologies near Earth. The mission is named for astrophysicist Eugene N. Parker, whose work predicted the solar wind.