NASA has launched its mission to send a satellite closer to the sun than ever before, with the Parker Solar Probe launching in Florida.
The Parker Probe is named after astrophysicist Eugene Parker, who first described solar wind in 1958.
It is the first time NASA has named a spacecraft after a living person.
Over seven years, Parker will make 24 loops around the sun to study its physics.
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It will get to within 6.13 million kilometres of the sun's surface. The previous closest is 43 million kilometres.
"I realise that might not sound close, but imagine the sun and the Earth were a metre apart. Parker Solar Probe would be just 4cm away from the sun," Dr Nicky Fox told the BBC.
Parker will travel at speeds of up to 190km/s and will face temperatures of around 1300degC.
In six weeks, Parker will make a pass of Venus before its first encounter with the sun six weeks after that.