MT LAUREL, New Jersey — SpaceX is asking the FCC for permission to operate all 4,400 of its first-generation Starlink satellites at much lower altitudes than previously planned.

Of the 12,000 Starlink satellites SpaceX plans to eventually launch in its quest to build a global broadband network, the initial third — some 4,400 satellites with Ku-band downlinks and Ka-band uplinks — were originally approved to operate roughly 1,200 kilometers above Earth. Last April, the FCC approved SpaceX’s request to operate nearly 1,600 of the first-generation satellites at 550 kilometers.

On Friday, with its seventh Starlink deployment launch just days away, SpaceX asked the FCC for authorization to operate the remaining 2,800 of the 4,400 first-generation Starlink satellites between 540 and 570 kilometers instead of the 1,100 to 1,325-kilometer orbits originally approved.

SpaceX has touted lower altitudes as a key element of its plans to prevent space debris, since gravity will pull dead satellites below 650 kilometers into Earth’s atmosphere within 25 years.

The bulk of SpaceX’s planned constellation — a second-generation system of 7,500 V-band satellites the company has yet to start launching — are already cleared by the FCC for orbits between 335 and 346 kilometers.

SpaceX has deployed 362 Starlink satellites, including two prototypes, into 550-kilometer orbits. Its next 60 satellites are scheduled to launch aboard a Falcon 9 rocket April 22 from Cape Canaveral, Florida.

The April 17 request is SpaceX’s third time in 12 months seeking FCC permission to change its approved constellation architecture since the FCC first cleared the company in 2018 to provide service with the 12,000-satellite megaconstellation.

Following last April’s approval of SpaceX’s request to operate 1,584 first-generation Starlink satellites at lower altitudes, the FCC in December approved a follow-up request to divide those satellites among three times as many 550-kilometer orbital lanes. SpaceX said the change would accelerate Starlink coverage for the contiguous United States.

Both of SpaceX’s prior requests for constellation changes were met with resistance. A half-dozen satellite operators, for example, urged the FCC to delay or reject the December request for more orbits.

SpaceX is anticipating resistance to its latest proposed change from smallsat companies that operate or plan to operate satellites near Starlink but without propulsion.

In its April 17 request, SpaceX told the FCC that it has “repeatedly made clear that it intends to conduct active maneuvers to avoid collisions with both debris and other spacecraft throughout the life of its satellites.” Starlink satellites have five-year design lives.

Astronomers may also resist the altitude change, since Starlink satellites are brighter in lower orbits. SpaceX said the lower orbit could have an upside for astronomers, however, since Starlink satellites would spend more time in Earth’s shadow not catching the sun’s glare.

SpaceX has found some success reducing reflectivity with DarkSat, a Starlink satellite painted with a dark coating, but optical interference remains a concern for astronomers. In its April 17 filing, SpaceX said it is “developing new mitigation efforts that it plans to test in the coming months.”