We’ve been looking up and wondering about the sun and stars since time immemorial— but up until now, all our observations have been from a distance because of the intense heat our home star generates. That will change soon — thanks to the Parker Space Probe that will launch August 11 (today). This new probe will be able to touch the sun — or at least its outer atmosphere. How can the new solar probe stand up to the heat?
The Parker Space Probe
The temperature in the sun’s corona can reach upwards of a million degrees— much hotter than the surface of the sun, which usually sits at just under 10,000 degrees Fahrenheit. Even the heat shielding that protects astronauts on their way home from the International Space Station can’t stand up to that — even though it’s designed to stand up to the 3,000-degree heat of atmospheric reentry.
How, then, can the Parker Space Probe hope to survive the intense heat of the sun’s corona?
According to NASA, it all comes down to the difference between heat and temperature. Heat measures the transfer of energy, while temperature measures how fast the individual particles are moving. The denser the atmosphere, the more heat can get transferred. In the sun’s corona, the particles are moving very fast — so the temperature is very high — but the density is very low, so the particles can’t transfer much of this heat.
This lack of density means,despite the million-degree temperatures, the Parker probe’s heat shield will only be experiencing temperatures of roughly 2,500 degrees Fahrenheit.
That doesn’t mean we — as humans — could safely traverse the surface of the sun. It’s still unbelievably hot out there, which is why the Parker probe needs a new type of heat shield.
Heat Shield Upgrades
The heat shield is something new, based loosely on the heat shielding that has protected space shuttles and rockets all these decades. It consists of three layers — two layers of carbon composite protecting a core of carbon foam. The surface that will be facing the sun also features a white coating that will help reflect even more of the sun’s heat and energy away from the vital components.
The shield is only four and a half inches thick and weighs 160 pounds— at least here on Earth — but it will be able to withstand temperatures of up to 2,500 degrees Fahrenheit and will keep the probe at a warm, but comfortable, 85 degrees.
There is one part that won’t be behind the heat shield, though —the Faraday cup. This sensor will allow the probe to take readings within the corona of the star’s magnetic field, solar winds and other information. NASA engineers designed this cup to survive the intense heat of the sun, while still collecting and relaying the information back to scientists on Earth.
The information from the Parker Space Probe will take the better part of a year to relay back home due to the magnetic interference our yellow star generates, but once we start getting information, we’ll better understand the star that sits in the core of our solar system. This probe will enable us to unlock the mysteries of the solar winds and their effect on our planet. It will also allow us to predict solar flares — something we haven’t been able to do before. We’ll be watching the Parker Space Probe closely, and can’t wait to see what it sends back!