A bipartisan committee in the US House of Representatives recently issued a report on the economic and technological competition between the United States and China and offered nearly 150 recommendations to "fundamentally reset" the relationship.

The report followed a year-long study of the competition between the countries since China's entry into the World Trade Organization in 2001.

"The Chinese Communist Party has pursued a multi-decade campaign of economic aggression against the United States and its allies in the name of strategically decoupling the People’s Republic of China from the global economy, making the PRC less dependent on the United States in critical sectors, while making the United States more dependent on (China)," the report states.

This initiative was a bipartisan effort led by US Reps. Mike Gallagher (R-Wis.) and Raja Krishnamoorthi (D-Ill.). In light of the concerns raised within the report, it sets out recommendations that will allow the United States to "chart a new path that puts its national security, economic security, and values" at the front and center of its relationship with China.

The recommendations cover a broad range of domains, but one suggestion on space was particularly notable. It involves locations where gravity is fairly stable, known as Lagrange points.

All roads lead to L2

The specific language in the report is this: "Fund NASA’s and the Department of Defense’s programs that are critical to countering the CCP’s malign ambitions in space, including by ensuring the United States is the first country to permanently station assets at all Lagrange Points. The CCP understands well the need for space-based operations and is developing formidable space capabilities to challenge US dominance in this domain."

So what are the Lagrange points, and why are they the new high ground in space? NASA has a good primer here. But the basic gist is that there are five points in the Earth-Sun system where the gravitational pull of the two bodies is effectively canceled out. Of the five Lagrange points, three are unstable, and two are stable. The unstable Lagrange points are L1, L2, and L3. The stable Lagrange points are L4 and L5.

Each of these Lagrange points has some strategic value, but some more than others. To understand how, Ars spoke with Laura Duffy, a space systems engineer for Canyon Consulting who served five years in the Air Force and is an expert in astrodynamics.

The first two points, L1 and L2, are particularly useful because of their proximity to the Moon. Although they are not entirely gravitationally stable, a spacecraft can fly a "halo" orbit around these locations and maintain their position with minimal propellant.

"L2 is specifically important because of its visibility to the far side of the Moon," Duffy said. "We cannot see that from the Earth, and China is headed there."

She is referring to the Queqiao relay satellite, which China launched into a halo orbit around L2 five years ago. It relayed communications from a lander on the far side of the Moon. This spacecraft, Chang'e 4, was the first vehicle humans have soft landed on the far side of the Moon. So China already has a demonstrated advantage in this area and plans to further it.

Duffy and a colleague at Canyon Consulting, James Lake, wrote about the strategic importance of China's efforts at L2 in the Space Force Journal two years ago. "China’s successful mission to the non-Earth facing side of the Moon has drawn the most concern from a military perspective because of the lack of monitoring capabilities on the far side of the Moon," they wrote.

Keeping a watchful eye on the Moon

Another reason why L1 and L2 are strategically valuable is that, due to the nature of orbital dynamics, they are excellent way stations. Assets positioned there, Duffy explained, require very little orbital energy—or delta V—to reach anywhere else in the Earth-Moon system. In other words, if you wanted to rapidly respond to some type of activity in cislunar space, these would be good locations to preposition assets.

Two other Lagrange points, L4 and L5, are also important. While they are quite distant, 60 degrees ahead of and behind the Earth in its 360-degree orbit around the Sun, they are stable. Moreover, they have strategic value for position, navigation, and timing services in cislunar space because they are farther out and can look at the system as a whole.

The House report provides no detailed information about what kinds of assets the United States and its allies should stage at the Lagrange points. But it seems clear that a first step will involve satellites that provide better situational awareness to monitor what China and other actors are doing in cislunar space.

“We’re in another space race back to the Moon, and this time it’s with China," Duffy said. "We want to be first because we want to set the norms."