The Solar-B satellite has three telescopes that will get the closest look yet at the Sun's magnetic fields. It will orbit the Earth for three years and spend three-quarters of the time in direct sunlight.
The satellite was launched on Saturday from the Uchinoura Space Centre in southern Japan in cooperation with the US and European space programmes, which will assess the data to complement their own research.
The rocket which loaded the Solar-B "succeeded" in putting the satellite into orbit, the Japan Aerospace Exploration Agency (JAXA) said on its website.
The Solar-B was given the Japanese name Hinode (sunrise), it said.
Satoki Kurokawa, a spokesman for JAXA, said: "The satellite will start its observation of the Sun's activity about two months later."
The data will also be analysed by the European Space Agency at Norway's Svalbard Islands in the Arctic Ocean, the only station on Earth that will be able to link with the Solar-B at all times.
The Solar-B has three telescopes - one optical, one X-ray and one ultraviolet - that were designed with the United States and Britain.
"Solar-B represents a very important step for solar physics"
European Space Agency scientist
"It will take three weeks for the satellite to adjust its orbit to a circular path from an ellipse path which it is currently following, and then researchers will open the lids of [the] three telescopes," Kurokawa said.
The Japanese researchers will operate observation of the satellite in the first six months, before it is taken over by other research institutes around the world, he said.
Bernhard Fleck, an European Space Agency scientist, said: "Solar-B represents a very important step for solar physics.
"Solar-B will be able to study the solar magnetic field at scales smaller than ever before, and connect its behaviour to the energetic and powerful processes at work on the Sun."
The Sun's magnetic field lines generate huge amounts of energy through solar flares when they interact. Coronal eruptions can affect the solar wind, bringing magnetic disturbances on Earth.
The satellite follows the Solar-A, also known by its Japanese name Yohkoh, which Japan launched in 1991 in collaboration with the United States and Britain.
Japan has been gradually expanding its space programme after an embarrassing failure in 2003 when it had to destroy a spy satellite 10 minutes after liftoff.
Japan on September 11 put into orbit its third spy satellite to monitor communist neighbour North Korea.