The Starlink constellation got 20 more satellites — 13 with direct-to-cell capabilities — thanks to another Falcon rocket launch from Vandenberg Space Force Base on Thursday night.

Loudly sounding its departure, the SpaceX rocket blasted off at 9:30 p.m. from Space Launch Complex-4 on the South Base with some spectators getting a double dose of sightings when the International Space Station also passed overhead. 

More than eight minutes after the launch, the first-stage booster returned to land on the droneship dubbed Of Course I Still Love You in the Pacific Ocean. 

The rocket was set to deploy the satellites slightly more than an hour after departure.

Starlink, made up of more than 6,000 satellites and growing, provides internet access across the world, including remote areas where service remains unavailable or unreliable. 

The 13 satellites with direct-to-cell capabilities will join others sent into orbit earlier this year to allow limited cellphone access to the system.

“Connecting cellphones to satellites has several major challenges to overcome. For example, in terrestrial networks cell towers are stationary, but in a satellite network they move at tens of thousands of miles per hour relative to users on Earth,” SpaceX said.

This requires seamless handoffs between satellites and accommodations for other factors that can challenge phone-to-space communications. 

“Cellphones are also incredibly difficult to connect to satellites hundreds of kilometers away given a mobile phone’s low antenna gain and transmit power,” SpaceX said.

Starlink satellites with the direct-to-cell payload are equipped with innovative new custom silicon, phased array antennas, and advanced software to overcome challenges and enable  service to cellphones on the ground.

The direct-to-cell network involving a constellation of hundreds of satellites will enable text service in 2024 and voice, data and Internet of Things (IoT) services in 2025.

SpaceX has partnered with cellphone companies including T-Mobile in the United States and others in Canada, Australia, Japan, Switzerland, Chile and Peru for the direct-to-cell service.

The first Starlink direct-to-cell satellites launched from Vandenberg earlier year. 

Thursday night’s Falcon launch of Starlink satellites was the second of two in as many days, with the first taking place from Florida on Wednesday.