China and Russia have signed an agreement to build their own space station orbiting the Moon within this decade.

The partners will together construct the "International Scientific Lunar Station" (ISLS), which will be manned by Chinese taikonauts and Russian cosmonauts. They envision ISLS as "a complex of experimental research facilities created on the surface and/or in the orbit of the Moon.

The space station will be designed to support a variety of research experiments "with the possibility of long-term unmanned operation with the prospect of a human presence on the moon," said a statement issued during the virtual signing ceremony.

The ISLS agreement was signed virtually by Zhang Kejian, Director of the China National Space Administration (CNSA), and Dmitry Rogozin, Director General of Roscosmos State Corporation for Space Activities (Roscosmos).

CNSA later said the joint development of ISLS will call for "planning, demonstration, design, development, implementation, and operation of scientific research station projects, including project promotion to the international aerospace community." Zhang Hanhui, China's ambassador to Russia, confirmed the agreement to build the ISLS.

Rogozin said ISLS will involve developing a space monitoring system and will play a role in both countries' deep space exploration programs. He said China and Russia will also likely cooperate on exploring asteroids and comets.

"The Chinese have grown a lot in recent years," said Rogozin. "We respect their results, and in principle they are a worthy partner for us."

It's unclear how the partnership with Russia to build the ISLS will affect their joint plans to build a manned base on the lunar surface. This Russo-Chinese lunar base, the International Lunar Research Station (ILRS), might also involve the European Space Agency (ESA). China unveiled its concept for the ILRS in August 2020.

The agreement to build ISLS was a surprise given China's previous opposition to an orbiting lunar space station. Pei Zhaoyu, deputy director at CNSA's Lunar Exploration and Space Program Center, had previously criticized as too costly the Lunar Gateway space station NASA plans to build starting 2024. Pei also said China intends to focus on building and sustaining ILRS.

The Lunar Gateway, however, will become the first operational lunar space station. This small space station small will serve as a solar-powered communication hub, science laboratory, short-term habitation module, and holding area for lunar rovers and other robots.

Developing the Lunar Gateway involves NASA, the Canadian Space Agency, the European Space Agency, Japan Aerospace Exploration Agency, and commercial partners. Russia chose not to participate in the Gateway project, dismissing it as too "U.S.-centric."