• NASA chief Bill Nelson discussed China's space ambitions
  • China's space program has been advancing 'stunningly fast' of late
  • China maintains that the concerns are unfounded and it's willing to cooperate

Is the U.S. embroiled in another space race? NASA chief Bill Nelson voiced his concerns, but China has said they're against the idea.

The U.S. is in a space race yet again—at least that's what NASA chief Bill Nelson said in an interview with Politico. The space race, of course, pertains to the period beginning in the 1950s when the U.S. and the Soviet Union were pitted against each other in the battle to reach space. And now, Nelson has expressed concerns about China's ambitious space endeavors, particularly concerning the Moon.

"It is a fact: we're in a space race. And it is true that we better watch out that they don't get to a place on the moon under the guise of scientific research," Nelson said, according to the outlet. "And it is not beyond the realm of possibility that they say, 'Keep out, we're here, this is our territory.'"

"If you doubt that, look at what they did with the Spratly Islands," he added, citing the highly disputed islands wherein China has reportedly built bases.

China has rapidly advanced in its space goals, having recently established its own new space station and also announcing its goal to send people to the Moon within the decade—advances that were not lost on U.S. officials.

"It's entirely possible they could catch up and surpass us, absolutely," Space Force Lt. Gen. Nina Armagno said during an event in Sydney, Australia, last November. "The progress they've made has been stunning, stunningly fast."

For its part, however, China has continued to stress that there is some misrepresentation in such voiced concerns.

"Some U.S. officials have spoken irresponsibly to misrepresent the normal and legitimate space endeavors of China," Liu Pengyu, the spokesperson for the Chinese Embassy in Washington, was quoted as saying by Politico. "China firmly rejects such remarks. Outer space is not a wrestling ground."

Pengyu stressed China's stance on using outer space peacefully. This was also key in Chinese President Xi Jinping's statement last November, wherein he reiterated China's hope to cooperate with other nations in space exploration and development.

In a letter to the UN/China 2nd Global Partnership Workshop on Space Exploration and Innovation, Xi stressed that China is "willing to deepen its cooperation and exchanges with other nations to advance space exploration and the peaceful use of outer space and to make better use of space technology for the interests of all people around the world."

To be clear, both China and the U.S. are part of the Outer Space Treaty, which states, among other principles, that outer space exploration should be for the "benefit and interests of all countries and shall be the province of all mankind." It is free for use by "all" the states and is "not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means."

Tourists take pictures of a NASA sign at the Kennedy Space Center visitors complex in Cape Canaveral, Florida