US space agency NASA has launched its mission to send a satellite closer to the Sun than any before.
The rocket carrying the Parker Solar Probe shot up into the sky from Cape Canaveral, Florida.
It came after a failed attempt the previous day, when a last-minute alarm caused the agency to miss its 65-minute weather window.
The probe is set to become the fastest-moving manmade object in history.
Its data promises to crack longstanding mysteries about the Sun's behaviour.
What will the probe do?
The probe aims to dip directly into our star's outer atmosphere, or corona.
It is travelling on board the Delta-IV Heavy rocket, which will hurl the probe into the inner Solar System.
The probe will zip past Venus in six weeks and make a first rendezvous with the Sun a further six weeks after that.
Over the course of seven years, Parker will make 24 loops around our star to study the physics of the corona, the place where much of the important activity that affects the Earth seems to originate.
The probe will dip inside this tenuous atmosphere, sampling conditions, and getting to just 6.16 million km from the Sun's broiling "surface".
"I realise that might not sound that close, but imagine the Sun and the Earth were a metre apart. Parker Solar Probe would be just 4cm away from the Sun," explained Dr Nicky Fox, the British-born project scientist who is affiliated to the Johns Hopkins Applied Physics Laboratory.
"We'll also be the fastest human-made object ever, travelling around the Sun at speeds of up to 690,000km/h - New York to Tokyo in under a minute!" she told BBC News.