China has always adhered to the principle of exploration and use of outer space for peaceful purposes, and has carried out international space exchanges and cooperation on the basis of equality and mutual benefit, peaceful use, and inclusive development, actively promoting the building of a community with a shared future for mankind in outer space, Xu Hongliang, spokesperson for the China National Space Administration (CNSA) told media in response to a claim recently made by the U.S. ambassador to China Nicholas Burns, who said he doesn't believe China has shown much of an interest in working with the United States on space exploration.

China has attached great importance to international cooperation in space, and always adopted an open and inclusive attitude toward space exchanges with the U.S., said Xu.

In 2006, the Chinese and U.S. space agencies established a joint working group on earth and space science and research. The two agencies have since communicated on multiple occasions in areas of common interest.

However, in 2011, the U.S. Congress passed the "Wolf Amendment," which banned the conduct of any China-U.S. joint scientific research related to the National Aeronautics and Space Administration (NASA) or coordinated by the White House Office of Science and Technology Policy (OSTP) without explicit authorization from the Federal Bureau of Investigation and the U.S. Congress.

Under the clause included in the U.S. spending bill, no Congress-approved funds may be used for NASA or OSTP to "develop, design, plan, promulgate, implement, or execute a bilateral policy, program, order, or contract of any kind to participate, collaborate, or coordinate bilaterally in any way with China or any Chinese-owned company."

China, on its part, welcomes scientists and researchers from all countries, including the U.S., to apply for access to lunar samples collected by the Chang'e-5 mission, Xu added. 

He expressed confusion regarding the U.S. simultaneously proposing cooperation and applications while some individuals from the U.S. government, who respect the "Wolf Amendment," have on various occasions said that the clause should be made permanent. The spokesperson questioned whether the U.S. is just playing "a word game."

Since the introduction of the "Wolf Amendment," communication between the two countries' space agencies has almost broken down. 

In 2015, the U.S. proposed that the State Department take the lead in establishing a civil aerospace dialogue mechanism, which received a positive response from China. Three rounds of talks have since taken place. However, a fourth meeting, which was scheduled to be hosted by the U.S., has yet to be convened despite calls from China.

Xu stressed that China has continued to push forward space cooperation with the U.S.

He said there are many voices in the U.S. calling for the "Wolf Amendment" to be cancelled, and for collaboration with China to resume in the areas of lunar and deep space exploration.

The CNSA has signed over 170 cooperation agreements and memorandum of understanding with more than 50 countries, space agencies and international organizations, including major space powers such as Russia and France, as well as developing countries such as Brazil and Pakistan.

These collaborations cover major projects in lunar and deep space exploration such as the Chang'e-4 and Tianwen-1 missions, as well as cooperation in the field of earth observation, which includes the development of the China-Brazil Earth Resources Satellite and the China-France Oceanography Satellite.

China has never issued any document, regulation or clause restricting space cooperation with the U.S., Xu said, adding that the international space community has been calling on the U.S. to remove the stumbling block that is the "Wolf Amendment."

On behalf of China's space agency, Xu called on "insightful individuals" in the U.S. to consider ways to remove that obstacle.

China "looks forward to conducting more extensive and in-depth international cooperation with countries around the world, to boost scientific research and enhance the common welfare of all mankind," said Xu.

China's Chang'e-5 mission

China's Chang'e-5 lunar probe, comprising an orbiter, a lander, an ascender and a returner, was launched in November 2020 and returned to Earth in December that year. It retrieved a total of 1,731 grams of lunar samples, mainly rocks and soil from the moon's surface.

More than 50 research results on the lunar samples brought back by the Chang'e-5 mission have been published in notable academic journals at home and abroad.

One of the most notable research results is about the history of volcanic eruptions in the Chang'e-5 landing region, which was published in October 2021 in three Nature papers. In September 2022, Chinese scientists announced that they discovered a new lunar mineral named Changesite-(Y) through research on the lunar samples. 

According to the latest international research, the lunar sample brought back to Earth by Chang'e-5 mission is much younger than those found by the Apollo and Luna missions.