NASA has successfully launched a spacecraft destined to become the fastest man-made object ever as it gets closer to the sun than we've been before. He was at Cape Canaveral for the launch - his first - which he called "impressive".
The probe was borne into the heavens atop a United Launch Alliance Delta IV Heavy rocket.
Scientists expect the $1.5-billion mission to shed light not only on our own dynamic sun, but the billions of other yellow dwarf stars - and other types of stars - out there in the Milky Way and beyond.
It is on an unprecedented quest that will take it straight through the edges of the corona, or outer solar atmosphere, just 3.8 million miles from the sun's surface.
The car-sized probe will give scientists a better understanding of solar wind and geomagnetic storms that risk wreaking chaos on Earth by knocking out the power grid.
These poorly understood solar outbursts could potentially wipe out power to millions of people.
A revolutionary carbon heat shield will protect it, while the tried-but-true practice of using water inside the craft to cool it down is also being utilised.
The sunlight is expected to heat the shield to just around 2,500 degrees Fahrenheit (1,371 degrees Celsius).
If all works as planned, the inside of the spacecraft should stay at just 85 degrees Fahrenheit.
The probe is set to make 24 passes through the corona, collecting data.
"We've been inside the orbit of Mercury and done incredible things, but until you go and touch the sun, you can't answer these questions", Nicola Fox, mission project scientist, told CNN.
"We are ready. We have the ideal payload. We have not been able to answer these questions".
It was the first rocket launch ever witnessed by Parker, a retired University of Chicago professor.
"Wow, here we go!"
"All I can say is "Wow, here we go, we're in for some learning over the next several years", he said when asked how he felt.
NASA's science mission chief, Thomas Zurbuchen, was thrilled not only with the launch, but Parker's presence.
"We've accomplished something that decades ago, lived exclusively in the realm of science fiction", he added, describing the probe as one of NASA's "strategically important" missions.
The 8-foot (2.4-meter) heat shield will serve as an umbrella that will shade the spacecraft's scientific instruments, with on-board sensors adjusting the protective cover as necessary so that nothing gets fried. It could be due to interactions between electrically charged particles and the sun's powerful magnetic field, or it could be the result of countless "nanoflares" governed by another mechanism.
By the time Parker gets to its 22nd, 23rd and 24th orbits of the sun in 2024 and 2025, it will be even deeper into the corona and traveling at a record 430,000 mph (690,000 kilometers per hour).