It is set to fly into the Sun's corona within 3.8 million miles (6.1 million km) of the solar surface, seven times closer than any other spacecraft.
Eastern on Sunday after an initial launch attempt on Saturday was scrubbed because of a last-minute technical glitch.
The Solar Probe Cup, dubbed "the bravest little instrument", is a sensor that will extend beyond the heat shield to "scoop up samples" of the Sun's atmosphere, according to Professor Justin Kasper of the University of MI.
The Parker Solar Probe won't touch the sun's surface, but it will monitor its electric and magnetic fields as well as the flow of plasma and solar-wind particles through the corona.
Roughly the size of a small vehicle, PSP will get almost seven times closer to the sun than any previous spacecraft. Eugene Parker is a University of Chicago professor emeritus in physics who first proposed the concept of the solar wind.
In order to reach an orbit around the sun, the Parker Solar Probe will take seven flybys of Venus that will essentially give a gravity assist, shrinking its orbit over the course of almost seven years. The spacecraft will also be prepared for the first of seven planned Venus flybys scheduled for October 2.
The craft will be the fastest manmade object ever - flying at speeds of 430,000mph - and endure temperatures of more than 1,300C while looping around the Sun a planned 24 times. Along the way, the spacecraft will gather data to try and solve some of the sun's great mysteries.
Scientists have been debating these questions for decades but NASA said technology has only come far enough in the past few decades to make the solar mission a reality.
"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.
These solar outbursts are poorly understood, but pack the potential to wipe out power to millions of people.
More knowledge of solar wind and space storms will also help protect future deep space explorers as they journey toward the Moon or Mars.
Parker, who first detailed the possibility of solar winds all the way back in 1958, said of the launch, "Wow, here we go!"
"I really have to turn from biting my nails in getting it launched, to thinking about all the interesting things which I don't know yet and which will be made clear, I assume, over the next five or six or seven years", Parker said on NASA TV.
But then, the launch of NASA's Mariner 2 spacecraft in 1962 - becoming the first robotic spacecraft to make a successful planetary encounter - proved them wrong.
It is said the data gathered by the car-sized probe will "revolutionise" our understanding of the star, which has a huge impact on Earth.