A specialized probe 60 years in the making will soon be launching into space on a mission to “touch” our sun for the very first time.
NASA’s specialists were on hand on Friday to discuss details of the Parker Solar Probe‘s $1.5-billion mission, and the technology that will keep the probe from burning to a crisp as it flies through the star’s outer layer, known as the corona.
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The probe is currently scheduled to launch on the morning of August 6 aboard a Delta IV-Heavy rocket. From there, it will begin its journey toward the heart of the solar system, passing by Venus about six weeks later.
The rocky planet will be used to slow the craft down, and then the probe will begin a series of orbits that will take it around the sun 24 times over the next seven years, passing by Venus several times and getting closer and closer to the sun with each orbit. It will download data back to Earth when it comes back toward us on each orbit.
The closest solar flyby will bring the Parker Solar Probe to a point 6.1-million kilometres above the surface of the sun, nearly seven times closer than the record mark set by the German Helios 2 spacecraft in 1976.
By then, it will also be moving at a very brisk speed: 620,000 km/h.
“We’ve looked at [the sun] in every single different way you can imagine … but we need to get into this action region, into the regions where all these mysteries are actually occurring,” explained project scientist Nicky Fox on Friday.
NASA’s team hopes to gather more information about why solar winds are so fast, and why the sun’s corona is so much hotter than the actual surface of the star. They also hope that the mission will lead to better predictions for so-called “space weather” in the future. A temperamental sun can cause major problems with technology here on Earth.
The corona can hit temperatures in the millions of degrees, but the probe itself will only need to contend with 1,370 C at its closest approach. Fox explained that this discrepancy is due mainly to the coronal density. It’s akin to heating your oven to 400 C and then putting your hand inside — the heat won’t burn you unless you touch one of the surfaces.
Still, 1,370 C is hot. And the probe has several layers of protective technology to keep the scientific instruments at room temperature. The most important one is a 4.5-inch thick heat shield made largely of carbon foam. It’s lightweight but effective.
NASA scientists demonstrated how it could stand up to a blowtorch without transferring any heat to the other side on Friday.
There’s also a water-based cooling system that circulates water through the back-end of the probe and radiates excess heat out into space to keep the instruments from burning up.
Finally, sensors mounted all over the probe are designed to detect how much energy is hitting the craft. Seven sun sensors, for example, should never actually be hit by direct sunlight. The moment one is, the spacecraft knows it’s tilted the wrong way and adjusts thrusters. No human being will be making these decisions.
“She’s highly, highly autonomous,” said Fox of the probe. “She has to look after herself when she’s in this coronal region … These are kind of the big technology leaps we’ve had to make.”
Fox added that while everything NASA does is pretty remarkable, this mission is in a class by itself. It’s taken decades to get to the point where the technology can allow the probe to survive.