World's first mission to touch the Sun lifts off: NASA

Lift-off took place from Space Launch Complex 37 at Cape Canaveral Air Force Station in the US early today.

The launch of the United Launch Alliance Delta IV Heavy rocket carrying the spacecraft was scrubbed yesterday due to a violation of a launch limit, resulting in a hold.

The car-sized spacecraft will travel directly into the Sun's atmosphere, about four million miles from its surface - and more than seven times closer than any spacecraft has come before, thanks to its innovative Thermal Protection System.

The USD 1.5 billion mission will perform the closest-ever observations of a star when it travels through the Sun's outer atmosphere, called the corona.

It will make 24 passes through the corona during its seven-year mission. The mission will rely on measurements and imaging to revolutionise our understanding of the corona and how processes there ultimately affect near-Earth space.

The Parker Solar Probe carries a line-up of instruments to study the Sun both remotely and in situ, or directly. Together, the data from these instruments should help scientists answer three foundational questions about our star.

A Sun-skimming mission like Parker Solar Probe has been a dream of scientists for decades, but only recently has the required technology - like the heat shield, solar array cooling system, and fault management system - been available to make such a mission a reality.

Parker Solar Probe will explore the corona, a region of the Sun only seen from Earth when the Moon blocks out the Sun's bright face during total solar eclipses.

The corona holds the answers to many of scientists' outstanding questions about the Sun's activity and processes.