Update for 11 p.m. EDT: SpaceX has successfully launched its 1st 60 Starlink satellites into orbit. Deployment is coming up next. Read our full story here!
SpaceX will make some history tonight (May 23), if all goes according to plan.
A two-stage Falcon 9 rocket carrying the first 60 satellites in SpaceX's Starlink internet constellation is scheduled to lift off at 10:30 p.m. EDT (0230 GMT on May 24) from Florida's Cape Canaveral Air Force Station.
Together, the five dozen spacecraft weigh about 18.5 tons (16.8 metric tons) — more than any other payload that SpaceX has ever launched, company founder and CEO Elon Musk said. (The previous high was 10.6 tons, or 9.6 metric tons, set in January 2017 with the launch of 10 Iridium NEXT communications satellites.)
SpaceX will also be treading new ground with the deployment of this Starlink batch. Rather than rely on 60 distinct spring-based deployment mechanisms, SpaceX will simply spin the satellites off the Falcon 9's upper stage.
"Each of the satellites on the stack has a slightly different amount of rotational inertia," Musk said during a call with reporters last week.
Deployment therefore "will almost seem like spreading a deck of cards on a table," he added. "So, this will look kind of weird compared to normal satellite deployments. And there actually may be a small amount of contact between the satellites, but it's very, very slow, and the satellites are designed to handle it."
The 60 spacecraft will spin free into low Earth orbit (LEO), 273 miles (440 kilometers) above our planet. They will then use their onboard krypton-powered thrusters to get to their operational altitude of 342 miles (550 km).
Many other Starlink launches will follow this one. The constellation, which is designed to provide affordable internet service to people around the world, needs about 400 satellites to provide "minor" coverage and 800 or so for "moderate" coverage, Musk said. And if things go really well, the network could eventually be about 12,000 strong, SpaceX representatives have said.
That brings us to another historic first SpaceX hopes to notch with Starlink in the near future.
"No one has ever succeeded in making a commercially viable low Earth orbit communications constellation right off the bat," Musk said. "I believe we will be successful, but it's far from a sure thing."
SpaceX will likely have to overcome some competition to make this happen. Several other companies, including OneWeb and Amazon, plan to launch internet megaconstellations of their own soon.
If Starlink does indeed succeed, Musk's long-held goal of Mars colonization could get a big boost. SpaceX hopes to use Starlink revenue to fund the development of Starship and Super Heavy, the reusable spaceship and rocket the company is developing to ferry people around the solar system.
The 60-satellite tally will not be a SpaceX record, by the way. In December 2018, a Falcon 9 lofted 64 tiny spacecraft to Earth orbit — the most ever launched aboard a single rocket from American soil. (India's Polar Satellite Launch Vehicle set the international record with a 104-satellite liftoff in February 2017.)
The December 2018 mission was the first SpaceX launch to feature a twice-flown Falcon 9 first stage. The first stage lifting off tonight has also flown twice before; it also lofted communications satellites in September 2018 and January of this year.
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Mike Wall's book about the search for alien life, "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), is out now. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.