Surviving the INFERNO
Parker will pass closer to the Sun than any human-made object before it, but how will it stay safe?
To survive temperatures up to 1,400ºC at close quarters to the Sun, Parker is equipped with the Thermal Protection System (TPS): a sun shield 12cm thick and over 2m in diameter.
“The TPS is made of super-thin sheets of a carbon material a bit like what’s used in graphite golf clubs and tennis rackets,” says Fox. “Then there’s foam in-between. This is covered in a white alumina, like a ceramic. That reflects a lot of the Sun’s light and the rest is absorbed and used to keep the rest of the spacecraft warm. It sounds ironic, but we’re almost more concerned about things getting cold rather than getting hot.”
Behind the shield Parker needs to be heated because the instruments operate best at room temperature. Though it might be scorching in the sunshine, it’s cool in the shade and without an atmosphere to move the heat around, temperatures drop dramatically. Maintaining this delicate balance requires Parker to stay precisely aligned so that its instruments are always in shadow. With an eight-minute delay between Earth and the Sun there’s no way that Parker could be controlled from the ground.
“She has to look after herself,” says Fox. “If a sensor’s in the sunlight when it shouldn’t be, Parker has to figure out what thruster it needs to fire to turn. The sheer amount of technology that had to be developed is why Parker has taken 60 years in development. It’s not a forgiving environment we’re going to.”
Parker’s Thermal Protection Shield (TPS) undergoes vibration tests