China plans to launch the world's largest and most advanced space solar telescope (SST) into an orbit circling the earth in 2008, the state's leading astronomer said Friday.

Via this telescope, said Ai Guoxiang, who heads the National Astronomical Observatories, Chinese scientists could engage in the study of one of the most difficult global scientific enigma, or the research on solar physical frontiers.

The SST, with a caliber of one meter, will be carried into the 735-km-high earth synchronous orbit, Ai, also academician of the Chinese Academy of Sciences (CAS), said in an exclusive interview with Xinhua.

The SST will be used to study the solar magnetic field, fine structures of the sun surface, the energy accumulation and release of solar flares and sun-earth interaction, Ai said.

The solar magnetic field, which dominates solar activities, is very hard to be measured. British Journal of Physics listed observation of the solar magnetic field among the four most difficult physical issues of the 21st century, together with quanta gravitation, fusion-related energy and pyro-superconductivity.

Before building space telescopes, global scientists gazed at the sun via earth surface-based telescopes. However, the observation from the earth will be affected by the aerosphere, which makes some key scientific data no so accurate.

Japan and the United States are now jointly developing a SST, coded as SOLAR-B. With a diameter of 0.5 meter, SOLAR-B has half capability in optical resolution than that of the China-made solar telescope.

The scheduled launch of SOLAR-B into space in 2005 has been delayed for some technical reasons, according to sources.

The CAS, who parents the Observatories and the Chinese Research Institute of Space Technology, developed the first Chinese SST, including five parts such as main optical telescope, super-ultraviolet telescopes, wide-band spectrograph, helium spectrum telescope and radio spectrograph, from 1992.

The SST body, costs 80 million yuan (about 9.66 million US dollars), could be used three years in space.

Jin Shengzhen, principal investigator for the project, said Chinese SST will cover a round size, with a diameter of 70 kilometers, on the solar surface.

As a fixed star nearest to the earth, the sun is the only source of light and heat for the earth. Scientists regarded the solar research as the key to unraveling the evolution of the solar system and even the whole cosmos.

Solar research labs in developed countries said Chinese astronomers could take treasured solar data with this ambitious plan.

Experts estimate the total investment into the project at one billion yuan (around 120 million US dollars). They, however, say it worthy for improving technologies in remote sensing, global positioning and satellite data processing in China.

The United States, Japan and a few other developed countries launched more than 130 spacecraft in solar observation, 20 out of which are still running in space.

By 2010, the United States plans to tunnel 1.5 billion dollars, the biggest sum of budget in the same period funded by the National Aeronautics and Space Administration, on space solar observation.