SpaceX is set to launch another batch of broadband internet satellites into orbit on Saturday while the company's new spaceship sits docked to the International Space Station.

The launch is part of the Starlink project, Elon Musk's plan to blanket Earth in high-speed satellite internet. Despite a few bumps so far — including astronomers' fears that the satellites could interfere with telescopes on Earth — Starlink is plowing ahead.

SpaceX is planning three internet-satellite launches within 18 days in June; the first happened on June 3, and this one will be the second. With the historic astronaut launch the company accomplished on May 30, that would be four rocket launches in less than four weeks, a feat that would have been almost impossible to imagine a few years ago.

The next batch of Starlink satellites is set to careen into space atop the same type of Falcon 9 rocket that SpaceX used to launch NASA astronauts in its Crew Dragon spaceship.

The rocket's booster is designed to be reusable — it returns to Earth after detaching during the launch and lands itself on either a drone ship at sea or a launchpad in Cape Canaveral, Florida.

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SpaceX's Demo-2 mission, launched with a Falcon 9 rocket, lifting off with the NASA astronauts Bob Behnken and Doug Hurley inside a Crew Dragon spaceship.
Tony Gray and Tim Powers/NASA

The next batch of about 60 Starlink satellites, scheduled to launch at 5:21 a.m. ET on Saturday, will join about 480 others that the company has sent into orbit since February 2018.

SpaceX has sought government permission to put a total of 42,000 satellites into orbit to form a "megaconstellation" around Earth. Musk has said he hopes Starlink will get rural and remote regions online with affordable, high-speed web access.

But the reflective satellites have appeared as bright, moving trails in the night sky that can photobomb astronomers' telescope observations and blot out the stars.

"If there are lots and lots of bright moving objects in the sky, it tremendously complicates our job," the astronomer James Lowenthal told The New York Times in November. "It potentially threatens the science of astronomy itself."

'It will look as if the whole sky is crawling with stars'

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SpaceX CEO Elon Musk speaks at the Satellite Conference and Exhibition in Washington in March.
AP Photo/Susan Walsh

Musk had suggested that SpaceX would send up batches of Starlink satellites every two weeks throughout 2020, for a total of 1,400 by the end of the year. But Saturday's launch will be only the ninth since Starlink began two years ago.

The company appears to be picking up the pace this month, however, with a total of 180 satellites in three launches.

After SpaceX launched its first set of Starlink satellites, many astronomers were alarmed by how bright the new objects were. In the days after the launch, people across the world spotted the train of satellites, like a line of twinkling stars.

"I felt as if life as an astronomer and a lover of the night sky would never be the same," Lowenthal told The Times.

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An astronomer in the Netherlands captured the Starlink train zooming across the sky shortly after its launch.
Vimeo/SatTrackCam Leiden

If SpaceX launches thousands more satellites, he added, "it will look as if the whole sky is crawling with stars."

That's a challenge for telescopes on Earth that look for distant, dim objects. Picking up these false stars could mess with astronomers' data, since a single satellite could create a long streak of light across a telescope's long-exposure images of the sky. That might block the view of the objects astronomers want to study.

Future Starlink satellites might get sun-blocking visors

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An illustration of SpaceX's Starlink satellite internet constellation in orbit around Earth.
SpaceX

SpaceX has been talking with astronomical associations about reducing its satellites' effect on Earth's telescopes.

The Starlink batch that launched earlier this month included a satellite with built-in visors to block the sun's reflection. SpaceX has said that starting with one of its later June launches, all satellites will have those visors going forward.

SpaceX has also launched an experimental satellite painted black to reduce the amount of light it reflects — that reduced the satellite's brightness by 55%, it said.

However, neither black paint nor a visor will stop the satellites' radio waves from interfering with telescopes.

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SpaceX stuffed a fleet of 60 Starlink internet-providing satellites into the nose cone of a Falcon 9 rocket for launch in May 2019.
Elon Musk/SpaceX via Twitter

SpaceX aims to finish the entire Starlink project in 2027. If the network does wind up with 42,000 satellites, it will have launched more than eight times the total number of satellites in orbit today.

Adding that much more material to Earth's orbit could increase the risk of space collisions. In the worst-case scenario, too many crashes in a series could turn the region into a minefield of debris, creating a spiraling space-junk disaster that could cut off our ability to leave Earth.

Last year, a near-collision with a Starlink satellite forced the European Space Agency to maneuver its own spacecraft out of the way.

SpaceX has said that to avoid leaving dead spacecraft in orbit (thereby contributing to the accumulation of space junk and increasing the risk of collisions), its satellites will automatically deorbit at the end of their lifespans.

The company appeared to be testing the deorbiting mechanism when one of its satellites fell into Earth's atmosphere and burned up in February, the astronomer Jonathan McDowell said.

After launching at least 500 more satellites, SpaceX plans to boot up Starlink, then build toward a floating internet backbone that would bathe most of the planet in ultra-high-speed web access.

"For the system to be economically viable, it's really on the order of 1,000 satellites," Musk said in May 2019, "which is obviously a lot of satellites, but it's way less than 10,000 or 12,000."

After this batch, the next Starlink launch is scheduled for June 22.