During the mission, the craft will make 24 orbits around our star, while passing by Venus seven times for gravity assists. The probe will employ its suite of instruments to help unlock the mysteries of the sun, while trying to survive the encounter with our star. Protecting the craft is a one-of-a-kind heat shield, an engineering marvel built to withstand searing temperatures of 1,400 degrees Celsius (2,550 degrees Fahrenheit) during the probe’s closest approach, Fox said.
If all goes as planned, the spacecraft will orbit the sun, with the shield taking the brunt of the heat, while the key parts of the spacecraft (the instruments and solar cells) remain closer to room temperature. [Watch Purple Lasers Light Up NASA's Parker Solar Probe in Test]
By taking a wealth of measurements and images, the probe is expected to revolutionize our understanding of the sun — in particular, the corona and the solar wind. Why specifically are we going to the corona? According to Fox, "That's where all the magic happens."
As the probe's namesake, Eugene Parker, proposed many decades ago, we know that the sun's shimmering, hazy atmosphere, known as the corona, is approximately 300 times hotter than the star's surface. But this seems to break the laws of nature, Fox said: She compared the sun to a campfire, but as you walk away from the fire, you somehow get hotter.
Parker himself proposed one of the leading explanations for why the corona is so much hotter than the sun's surface, suggesting that the corona is superheated due "nanoflares." A complex system of plasma, magnetic fields, and energetic particles can spark solar explosions that trigger these flares. If an abundance of nanoflares erupts from the sun, that could explain the coronal heating.
There are many proposed explanations for what causes the heating, Fox said, but until we can sample the corona, we cannot test those ideas. This is where Parker Solar Probe comes in.
But that's not all it will do.