Japan's space agency launched a SOLAR-B observation satellite, developed jointly by Japan, the US and Britain, into orbit around the Earth, where it will study the sun's magnetic field.
An M-V rocket carrying the satellite lifted off from Uchinoura, about 620 miles south west of Tokyo, according to a live web broadcast by the Japan Aerospace Exploration Agency.
The agency, known as JAXA, confirmed that the satellite had separated from the rocket and its solar panels had been deployed.
The 1,984lb SOLAR-B incorporates a set of optical, extreme ultraviolet and X-ray instruments designed to investigate the sun's magnetic field in order to better understand the causes of solar flares.
The radiation from solar flares can damage electronic equipment, interrupts radio signals and affects the health of astronauts.