While Nasa scientists have meant to launch a solar mission for decades, cuts made to the space programme by successive presidents have hampered development, while "only recent technological advances in cooling systems and fault management have made it possible" says The Independent.
This will enable the probe to work on three main questions: why its atmosphere becomes hotter farther away from the surface of the Sun, how the solar wind of charged particles streaming out into space is born, and what causes the huge outbursts scientists call coronal mass ejections.
"Previous missions have been really important for solar science as we study from afar - and we can learn a lot from studying from afar - but Parker Solar Probe is actually going and touching, nearly kissing the sun, so we can learn so much more", said Elizabeth Congdon, the thermal protection system lead engineer at Johns Hopkins Applied Physics Laboratory. The gravity assist is planned for 2 October, when the probe will have to be on track and approach the Sun on 5 November.
The spacecraft has undergone a brutal regimen of testing at the APL and NASA's Goddard Space Flight Center.
The space agency is preparing to get closer to the sun than any other mission in history.
The four instruments onboard the spacecraft are a solar wind plasma suite, the Solar Wind Electrons Alphas and Protons (SWEAP) investigation; an electric and magnetic field suite (FIELDS); a wide field imager (WISPR); and the energetic particle suite, the Integrated Science Investigation of the Sun (ISʘIS).
It will blast off inside a Delta IV rocket from Cape Canaveral, Florida.
It will get about 4 million miles from the sun.
"Parker Solar Probe is going to answer questions about solar physics that we've puzzled over for more than six decades", said project scientist Nicola Fox of the Johns Hopkins Applied Physics Laboratory.
The mission was named after Eugene Newman Parker, a physicist who proposed a number of concepts about how stars give off energy.
Likewise, scientists hope the probe's small-scale, short-term analysis will improve space weather prediction models. While the launch window was due to close on August 19, NASA has managed to extend it for a few more days, until August 23.