In myth, Icarus flew too close to the sun, and the wax that held birds’ feathers together melted, and he fell into the sea and drowned. The designers of the Parker Solar Probe opted for a 4.5-inch thick carbon-composite shield to prevent such a tumble, allowing the probe to get as close as 3.83 million miles from the sun, and withstand temperatures that will reach nearly 2,500°F.
NASA said today the probe’s launch had been pushed back slightly, to as early as August 11, after finding a strip of foam inside the nose cone, or payload fairing, that protects the spacecraft during its launch and before it’s jettisoned into space. NASA said it has to perform additional inspection. As recently as 2017, a satellite failed to launch due to trouble with the payload fairing improperly jettisoning.
The Parker Solar Probe will come seven times closer to the sun than any previous mission, and answer questions about the solar corona, or the outer atmosphere of the sun. Counter-intuitively, the solar corona is hundreds of times hotter than the surface of the sun, and scientists have yet to find an explanation.
The probe will also delve into why the solar wind accelerates as it moves away from the sun. The solar wind comprises charged particles, magnetic fields, and plasmas (very high-temperature gases with effectively no electric charge), and it flows away from the sun to edge of the heliosphere and beyond. The heliosphere is the effective edge of the sun’s magnetic influences, through which the Voyager 1 probe ostensibly passed through in 2012, about 11 billion miles from the sun.
The mission also has the practical aim of better understanding so-called “space weather,” a term that sweeps in all the space-borne behavior of particles and fields, some of which can have large effects on Earth. This can include solar flares and coronal mass ejections, both of which can disrupt radio communications on Earth, disable satellites, and increase the risk of cancer or other health problems for passengers on some flight routes—and potentially cause more immediate harm to astronauts in space who are more directly exposed to hazardous particles.
No surprise, but the the probe relies on solar power to function, rather than the radioisotope thermoelectric generators (RTGs) powered by plutonium that are used for deep-space missions like the Voyager probes, and planetary rovers like Mars Curiosity.