The first ever spacecraft to fly directly toward the Sun is poised to blast off today, on a mission to plunge into our star's sizzling atmosphere and unlock the mysteries of the centre of the solar system.
NASA's car-sized, USD 1.5 billion Parker Solar Probe is scheduled to launch on a Delta IV Heavy rocket from Cape Canaveral, Florida during a 65-minute launch window that opens at 3:33 am (0733 GMT).
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.
"We are going to be in an area that is so exciting, where solar wind -- we believe -- will be accelerating," said NASA planetary science division director Jim Green.
"Where we see huge magnetic fields that are passing by us, as coronal mass ejections make their way out into the solar system."
"We are ready. We have the perfect payload. We know the questions we want to answer."
Parker said he was "impressed" by the Parker Solar Probe, calling it "a very complex machine."
"And last but not least, we have a white light imager that is taking images of the atmosphere right in front of the Sun."