A blazing United Launch Alliance Delta 4 Heavy rocket rose into the night sky from its launch pad at Cape Canaveral Air Force Station in Florida at 3:31 a.m. ET (12:31 a.m. PT), one day after concerns over a data glitch forced a postponement.
On the final three orbits, PSP flies to within 3.8 million miles of the sun's surface - more than seven times closer than the current record-holder for a close solar pass, the Helios 2 spacecraft, which came within 27 million miles in 1976, and about a tenth as close as Mercury, which is, on average, about 36 million miles from the Sun.
The craft will be protected from the heat of the sun by a revolutionary new heat shield. The first data download from the Parker Solar Probe is expected in early December after the probe reaches its first close approach of the sun in November.
"The Parker Solar Probe will help us do a much better job of predicting when a disturbance in the solar wind could hit Earth", said Justin Kasper, a project scientist and professor at the University of MI. Eugene Parker is a University of Chicago professor emeritus in physics who first proposed the concept of the solar wind.
The Parker Solar Probe's launch marked a special milestone for one solar scientist: Eugene Parker. Saturday morning's launch attempt was foiled by last-minute technical trouble. This followed earlier trouble in the countdown.
At a press conference last week, Parker said of his namesake mission: "I expect to find some surprises".
By coming closer to the Sun than any spacecraft in history, the unmanned probe's main goal is to unveil the secrets of the corona, the unusual atmosphere around the Sun.
Knowing more about the solar wind and space storms will also help protect future deep space explorers as they journey towards the Moon or Mars. "We are in for some learning over the next several years", Parker told NASA television. At closest approach, the solar shield of the probe will face temperatures approaching 1,377 degrees Celsius.
A mission to get up close and personal with the star has been on NASA's books since 1958 - but the technology necessary to make a small, compact spacecraft, light enough to travel at incredible speeds while surviving the extreme change in temperature, heat and radiation didn't exist yet. The shield's front surface will be able to withstand temperatures outside the spacecraft up to 2,500 degree Fahrenheit.
Finally, after two firings of the second-stage engine, the Parker Solar Probe and its Northrup Grumman solid-fuel upper stage were released from the Delta 4. That's further away than Parker but it will still need an impressive shield. 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. At this point, the probe will be moving at roughly 430,000 miles per hour, setting the record for the fastest-moving object made by humanity.