China is planning to launch a solar exploration satellite to a previously unexplored orbit between Earth and the sun for solar probe and space weather monitoring.

The appraisal work of Xihe-2 solar exploration mission to the Sun-Earth L5 Lagrangian Point is in the pipeline, Professor Fang Cheng from Nanjing University who is one of the satellite's designers, said on Thursday at the 10th Conference on Advanced Space Technology in Shanghai.

The solar probe is expected to be sent into the planned orbit around 2026 per the initial plan, aiming at exploring the origin and evolution of the magnetic field in the solar active region and revealing the three-dimensional structure and physical mechanism of solar bursts.

The Sun-Earth Lagrangian L5 point, approximately 150 million kilometers away from Earth, is a uniquely advantageous location for space weather research and monitoring, as it enables imaging of solar activity at least three days prior to a terrestrial viewpoint and measures the solar wind conditions four to five days ahead of Earth impact.

The satellite will be the world's first artificial probe to the point.

"The Sun-Earth L5 point is still a virgin place for exploration," said Fang. "It is scientifically meaningful and feasible in engineering."

It can also provide data for timely early warning and accurate forecasting of space weather, according to Fang.

On October 14, 2021, China sent its first solar exploration satellite Xihe into a sun-synchronous orbit to conduct solar H-alpha spectral imaging.

Lunar exploration with steady progress

In addition to the solar probe, the country's lunar exploration project is also advancing steadily.

Experts at the conference shared progress in the construction of a long-term underground lunar research station.

Compared with Earth, the moon does not have an atmosphere, resulting in a huge temperature difference between day and night, high-intensity cosmic radiation and micrometeorite impact, which will bring risks to the establishment of a long-term scientific research base there, said Zhang Chongfeng, deputy chief designer of China's lunar probe lander.

However, underground caves in lunar lava tubes can provide shelters free of temperature extremes, radiation, meteorite impact and moon dust, said Zhang.

Zhang's team has proposed their conception for the construction of a lunar cave base, which contains an energy and communication support center at the entrance, entry and return channels for personnel and equipment, and capsules for scientific research and residence inside the cave.

They are now mulling over the exploration plan of the caves.

(With input from Xinhua)