SpaceX successfully deployed 60 more Starlink internet satellites in orbit Saturday, continuing a record launch cadence while engineers assess a concern with Falcon 9 rocket engines that has delayed other missions, including the next crew flight to the International Space Station.

The 60 Starlink satellites blasted off from pad 40 at Cape Canaveral Air Force Station at 11:31:34 a.m. EDT (1531:34 GMT) Saturday. The mission was delayed from Thursday to allow time for engineers to assess a problem with a camera on the Falcon 9 rocket’s upper stage.

Nine kerosene-fueled Merlin 1D engines powered the 229-foot-tall (70-meter) launcher into the sky on a trajectory northeast from Cape Canaveral.

The rocket’s first stage shut down its engines and separated two-and-a-half minutes into the mission, beginning a controlled descent to a pinpoint landing on a floating platform parked some 400 miles (630 kilometers) northeast of the launch site.

The landing concluded the third trip to space and back for the reusable Falcon 9 booster — designated B1060 — and the touchdown occurred moments before the rocket’s upper stage delivered the 60 Starlink satellites into a preliminary parking orbit.

SpaceX did not try to catch the Falcon 9’s two-piece payload fairing as they fell back to Earth under parachutes. A nose cone structure damaged a net on one of SpaceX’s fairing recovery vessels on the company’s most recent launch Oct. 18.

Instead, SpaceX dispatched one of the boats from its fleet to retrieve the fairing structures from the Atlantic Ocean for inspections, refurbishment, and potential use on a future flight.

After coasting across the Atlantic Ocean, Europe and the Middle East, the Falcon 9’s upper stage briefly reignited its single engine at T+plus 44 minutes to inject the Starlink satellites into a near-circular orbit at an altitude of roughly 170 miles (275 kilometers) with an inclination of 53 degrees to the equator.

All 60 satellites, which were flat-packed on top of the Falcon 9 rocket for launch, separated from the upper stage at 12:34 p.m. EDT (1634 GMT). A live video feed from the rocket showed the flat-panel satellites receding from view as they flew south of Tasmania.

SpaceX’s Falcon 9 rocket lifted off from Cape Canaveral at 11:31am EDT (1531 GMT) with 60 more Starlink internet satellites, darting through clouds in an autumn sky on the way to orbit.

Continuing coverage: https://t.co/IKu6Gke7tj pic.twitter.com/BqAbclbc8F

— Spaceflight Now (@SpaceflightNow) October 24, 2020

The satellites, built by SpaceX in Redmond, Washington, were expected to unfurl power-generating solar arrays and prime their krypton ion thrusters to begin raising their orbits to an operational altitude of 341 miles (550 kilometers), where they will join more than 800 other Starlink relay stations to beam broadband internet signals across most of the populated world.

SpaceX plans to operate an initial block of around 1,500 Starlink satellites in orbits 341 miles above Earth. The company, founded by billionaire Elon Musk, has regulatory approval from the Federal Communications Commission to eventually field a fleet of up to 12,000 small Starlink broadband stations operating in Ku-band, Ka-band, and V-band frequencies.

There are also preliminary plans for an even larger fleet of 30,000 additional Starlink satellites, but a network of that size has not been authorized by the FCC.

SpaceX says the Starlink network — designed for low-latency internet service — is still in its early stages, and engineers continue testing the system to collect latency data and speed tests. In a filing with the FCC dated Oct. 13, SpaceX said it has started beta testing of the Starlink network in multiple U.S. states, and is providing internet connectivity to previously unserved students in rural areas.

On Sept. 28, the Washington Military Department announced it was using the Starlink internet service as emergency responders and residents in Malden, Washington, recover from a wildfire that destroyed much of the town.

Earlier this month, Washington government officials said the Hoh Tribe was starting to use the Starlink service. SpaceX said it recently installed Starlink ground terminals on an administrative building and about 20 private homes on the Hoh Tribe Reservation.

A catalog of Starlink satellites maintained by Jonathan McDowell, a widely-respected astronomer who tracks global spaceflight activity, indicated that 53 of the Starlink satellites have been deorbited since their launch, primarily test models that launched last year. Two other satellites have failed and another 20 appear have stopped maneuvering, leaving around 820 spacecraft presumably operational, according to McDowell.

Since Oct. 6, SpaceX has shot 180 Starlink satellites into orbit on three dedicated Falcon 9 rocket missions. That’s more satellites than in the entire constellation operated by Planet, which owns the second-biggest fleet of spacecraft in orbit.

As of this week, Planet had around 150 active SkySat and Dove Earth-imaging satellites in its fleet, a company spokesperson said.

SpaceX continues Starlink launches while engine issue delays other missions

The launch of three Starlink missions on Falcon 9 rockets this month occurred as SpaceX delayed other launches to study an issue with Merlin engines that aborted a Falcon 9 countdown Oct. 2 with a U.S. military GPS navigation satellite.

Elon Musk, SpaceX’s founder and CEO, tweeted after the abort that the countdown was stopped at T-minus 2 seconds after an “unexpected pressure rise in the turbomachinery gas generator,” referring to equipment used on the rocket’s nine Merlin first stage main engines. The gas generators on the Merlin 1D engines drives the engines’ turbopumps.

NASA announced Oct. 10 that the launch from the Kennedy Space Center of SpaceX’s first operational Crew Dragon flight to the International Space Station would be delayed from Oct. 31 until early to mid-November to allow time for engineers to study and resolve the engine issue.

Kathy Lueders, head of NASA’s human spaceflight programs, tweeted Oct. 21 that the space agency and SpaceX were making “a lot of good progress … on engine testing to better understand the unexpected behavior observed during a recent non-NASA launch.”

It’s too early to report findings at this point, as SpaceX continues testing to validate what’s believed to be the most credible cause,” Lueders tweeted.

She wrote that SpaceX is replacing one engine on the Falcon 9 rocket assigned to the Crew Dragon mission — known as Crew-1 — and one engine on the Falcon 9 booster designated for launch of a U.S.-European oceanography satellite next month from Vandenberg Air Force Base, California.

The engines being replaced displayed behavior during their ground testing that was similar to the “early-start behavior” noted during the aborted GPS launch Oct. 2., Lueders wrote.

The launch of the Sentinel-6 Michael Freilich oceanography satellite remains scheduled for Nov. 10 from California, Lueders said.

“We are also still working towards a mid-November launch for Crew-1,” she added. “We will want a few days between Sentinel-6 and Crew-1 to complete data reviews and check performance. Most importantly, we will fly all our missions when we are ready.”

The Crew-1 mission will launch four astronauts to begin a six-month expedition on the International Space Station. It follows a two-man Crew Dragon test flight that launched May 30 and concluded with a successful return to Earth on Aug. 2, the first orbital flight of astronauts to launch from U.S. soil since the retirement of the space shuttle in 2011.

In a press briefing Oct. 16, a NASA manager said engineers from NASA, the U.S. Space Force, and SpaceX are jointly investigating the engine problem that surfaced during the Oct. 2 countdown.

“I can tell you an incredible amount of data has been looked at, to include members from our commercial crew program which also has an upcoming Falcon flight,” said Tim Dunn, NASA’s launch director for the Sentinel-6 Michael Freilich mission.

In addition to testing at the launch base at Cape Canaveral, SpaceX removed engines from the Falcon 9 rocket for the GPS mission and returned them to the company’s test facility in McGregor, Texas, for detailed testing and reviews.

“We’ve learned a lot,” Dunn said. “There’s going to be some hardware implications as we move forward, depending on the engines installed on various rockets. The GPS mission obviously is affected. The NASA Crew-1 mission is affected. On Sentinel-6, we are looking at the engines that are on our first stage. We are going to work through what we need to do, but as of today, we have a path forward that allows us to do whatever necessary rework may be required and still maintain that Nov. 10 launch date.”

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Follow Stephen Clark on Twitter: @StephenClark1.

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