Nicky Fox, a project scientist at the Johns Hopkins University Applied Physics Lab, said: "The sun is full of mysteries".
The probe's main goal is to unveil the secrets of the corona, the unusual atmosphere around Sun. It will be subjected to brutal heat and radiation like no other man-made structure before.
NASA early Saturday scrubbed its planned launch of humankind's first probe to the sun, planning to try again Sunday morning.
The Parker probe will have tools to measure the sun's expanding corona and its flowing atmosphere known as the solar wind, which was first discovered by solar physicist Eugene Parker in 1958.
By better understanding the basic science of solar wind - how the sun's atmospheric particles accelerate and interact - scientists hope to more accurately model larger, more complex solar phenomena, and improve space weather prediction models.
As soon as the red pressure alarm for the gaseous helium system went off, a launch controller ordered, "Hold, hold, hold".
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The powerful Delta 4 Heavy and a solid-propellant upper stage will provide the energy needed to counteract Earth's 18-mile-per-second orbital velocity, allowing the Parker Solar Probe to fall into the inner solar system.
The probe is equipped with a 4 1/2-inch thick carbon-carbon heat shield created to withstand temperatures of about 2,500 degrees Fahrenheit.
Not only is the corona about 300 times hotter than the Sun's surface, but it also hurls powerful plasma and energetic particles that can unleash geomagnetic space storms, wreaking havoc on Earth by disrupting the power grid. "Some high-energy solar particles accelerate to almost half the speed of light, and we don't know why". Engineers tried to identifiy the problem, but the launch window - when a spacecraft can take off in the right direction due to the Earth's rotation - closed before they could make progress.
"It was just a matter of sitting out the deniers for four years until the Venus Mariner 2 spacecraft showed that, by golly, there was a solar wind", Parker said earlier this week.
The probe is protected by a 4in-thick shield that constantly repositions itself between the sun's power and the scientific instruments on board.