NASA launches historic probe to ‘touch Sun’

Muriel Hammond
August 15, 2018

That will be seven times closer than previous spacecraft.

"Aerojet Rocketdyne propulsion plays a critical role in all aspects of the Parker Solar Probe mission, from launch on the Delta IV, to the probe's safe cruise through space and approach of the Sun's atmosphere".

NASA on Sunday said it had launched Parker Solar Probe, the United States space agency's historic small car-sized probe, on its seven-year space odyssey that will take it gradually closer to the Sun at 3.8 million miles.

In reality, it should come within 3.83 million miles (6.16 million kilometers) of the Sun's surface, close enough to study the curious phenomenon of the solar wind and the Sun's atmosphere, known as the corona, which is 300 times hotter than its surface.

Solar wind is the stream of charged particles - primarily protons and electrons - that continuously flows outward from the sun through the solar system at a speed of about 1 million miles per hour.

"We're used to the idea that if I am standing next to a campfire, and I walk away from it, it gets cooler", said Alex Young, a solar scientist at NASA's Goddard Space Flight Center in Maryland. "Parker Solar Probe has begun its mission to "touch" the Sun", NASA said in a blog post, about two hours after the lift off.

The probe, named after American solar astrophysicist Eugene Newman Parker, will have to survive hard heat and radiation conditions.

The probe has been outfitted with a heat shield created to keep its instruments at a tolerable 85 degrees Fahrenheit (29 degrees Celsius) even as the spacecraft faces temperatures reaching almost 2,500 degrees Fahrenheit at its closest pass to the Sun. A plaque dedicating the mission to Parker was attached to the spacecraft in May.

The RL10 second stage engine helped send the Parker Solar Probe, developed by the Johns Hopkins University Applied Physics Laboratory, into a heliocentric orbit that ultimately will take it around the Sun 24 times.

"I suspect it's going to be complicated, and I suspect some of us will argue with each other as to exactly what's going on", he said before the launch.

The mission's objectives include "tracing the flow of energy that heats and accelerates the sun's corona and solar wind, determining the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind and explore mechanisms that accelerate and transport energetic particles".

The car-sized spacecraft will speed through space at 430,000mph - coming within four million miles of the Earth's nearest star by 2024.

Zurbuchen also described the probe as one of NASA's most "strategically important" missions.

"If you go out to the moon or if you're planning on going out to Mars or elsewhere, these solar energetic particles provide potentially a very unsafe radiation environment for astronauts", McComas said. Eugene Parker predicted the existence of solar wind 60 years ago. Parker's first paper was rejected, but it was saved by a colleague, Subrahmanyan Chandrasekhar, an astrophysicist who would be awarded the 1983 Nobel Prize for Physics. His work revolutionized our understanding of the sun and interplanetary space. Zurbuchen and Fox also presented Parker with NASA's distinguished public service medal.

The Parker Solar Probe will carry a chip with photos of Parker, his revolutionary paper and his message to the sun: "Let's see what lies ahead".

"I'm greatly honored to be associated with such a heroic scientific space mission", Parker said. "It's very exciting that we'll finally get a look". I'm sure that there will be some surprises.

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