Unlocking the Sun: Inside NASA and ESA’s Daring Missions to Touch the Solar Inferno
Parker Solar Probe, launched August 12, 2018 on a Delta IV Heavy, became NASA’s first mission to fly through the Sun’s corona and “touch the Sun” in April 2021 when it crossed the Alfvén critical boundary during its 8th orbit. At its closest approaches Parker reaches about 3.8–4 million miles (6.2 million km) from the Sun, roughly 9 solar radii, traveling faster than 430,000 mph (700,000 km/h). The probe’s heat shield is a 4.5-inch-thick carbon-composite foam sandwich that keeps instruments near room temperature while the shield surface heats to about 2,500°F (1,377°C). Parker carries four instrument suites—FIELDS, SWEAP, IS☉IS, and