A similar process is playing out with the probe's speed: At the peak of its first two perihelions, the spacecraft traveled at about 213,200 mph (343,000 km/h), also breaking records, but future close approaches will see the Parker Solar Probe moving still faster. These close grazes are anxious times for scientists and engineers on the mission because the spacecraft is out of communication with Earth for several days before and after each perihelion. The radio silence is designed to let the spacecraft focus on keeping its instruments tucked safely behind the thick shield that protects them from the incredible heat...