WASHINGTON — A mysterious Russian military satellite parked itself between two Intelsat satellites in geosynchronous orbit for five months this year, alarming company executives and leading to classified meetings among U.S. government officials.

The Russian satellite, alternatively known as Luch or Olymp, launched in September 2014 and seven months later moved to a position directly between the Intelsat 7 and Intelsat 901 satellites, which are located within half a degree of one another 36,000 kilometers above the equator. At times, the Russian satellite maneuvered to about 10 kilometers of the Intelsat space vehicles, sources said, a distance so close that company leaders believed their satellites could be at risk.

The satellite’s movements were highlighted by Brian Weeden, technical adviser at the Secure World Foundation, in an Oct. 5 analysis of Russian rendezvous and proximity operations for SpaceNews’ sister publication, the Space Review.

“This is not normal behavior and we’re concerned,” Kay Sears, president of Intelsat General, the government services arm of Intelsat, said in an Oct. 8 interview with SpaceNews. “We absolutely need responsible operators. Space is a domain that has to be protected.”

Sears stressed that the Russian satellites did not interfere with Intelsat’s satellite services.

Many in the space community believe the incident marks one of the first publicly documented times a commercial operator has been subject to this kind of approach by a foreign military satellite. The episode also raises questions about what kind of recourse commercial satellite companies have in these situations.

“Under the current space treaties, private sector operators don’t have much recourse other than to ask their government for help,” Weeden said in an email to SpaceNews.

The maneuvers of the Luch satellite have led to several classified meetings within the Defense Department, a source told SpaceNews.

The satellite’s movements were observed months after the Air Force said it was watching two other Russian military satellites, each with maneuvering capabilities that are consistent with, but not necessarily indicative of, an on-orbit antisatellite weapon.

Those satellites, known as Cosmos 2499 and 2504, have been the subject of widespread speculation among space tracking experts and policy analysts. They are among the reasons that Defense Department officials have been sounding alarms over the past year or two about threats to U.S. space systems from China and Russia.

The Luch satellite launched on Sept. 28, 2014, aboard a Proton-M rocket from the Baikonur Cosmodrome in Kazakhstan. While there are several theories about the satellite’s mission, many observers of the Russian space program believe it has a role in signal intelligence or communications, Weeden wrote in his paper.

In the first months following the launch, the Luch satellite moved several times before stopping at 18.1 degrees west longitude, due south of the western tip of Africa, around April 4. This placed it between Intelsat 7, which was located at 18.2 degrees west, and Intelsat 901, located at 18 degrees west, Weeden’s paper said.

Intelsat, which operates 75 satellites, has never faced a similar situation, Sears said,

In a response to questions from SpaceNews, Air Force Capt. Nicholas Mercurio, a spokesman for U.S. Strategic Command’s Joint Functional Component Command (JFCC) for Space, said in an Oct. 8 email that the Luch satellite has come within 5 kilometers of another satellite on three occasions since its launch. He did not identify the satellite.

However, the Air Force data are predictions based on drift rates, an industry source said, adding that the Russian satellite was not closer than 10 kilometers to either of the Intelsat satellites.

Mercurio referred further questions about the satellite to the Russian government. The Russian Embassy did not immediately respond to questions from SpaceNews.

Five kilometers is extremely close for geosynchronous satellites and usually requires satellite operators to closely work together to minimize the chance of a collision.

The Russian satellite was so close, Sears said she believed “the safety of flight” of the Intelsat satellites was at risk. As a result, Intelsat tried to reach the Russian satellite’s owners directly and through the Defense Department but did not receive a response.

“They’re not communicating,” Sears said. “They’re not collaborating with us. The safety of flight that’s so important to operators is being put at risk and that’s concerning. That’s just irresponsible. If we all did that, we would have a lot of accidents.”

Intelsat is one of a handful of companies working with Air Force officials as part of a pilot program known as a commercial integration cell within the Joint Space Operations Center, the Defense Department’s nerve center for space operations. The commercial integration cell gives the Air Force a better sense of how commercial satellites are operated and how they could more closely coordinate with military space capabilities.

As a result, Intelsat and the Air Force have traded more detailed information about their operations and the Luch satellite in an accelerated timeline, Sears said.