Amazon passed a critical early milestone in developing the hardware needed for its planned Project Kuiper satellite internet network, the company announced on Wednesday.

Jeff Bezos’ e-commerce and technology giant said its Kuiper team completed initial development of the antenna that will be housed in its “low-cost customer terminal,” which will connect users to Amazon’s network. Project Kuiper represents Amazon’s plan to launch 3,236 internet satellites into low Earth orbit — a system that would compete with SpaceX’s Starlink network.

Amazon said it has been field testing the Kuiper antenna “in multiple environments,” including “streaming 4K-quality video from a geostationary (GEO) satellite.” Geostationary satellites are typically in orbit about 35,000 kilometers from Earth, which Amazon noted is “approximately 50 times farther” than the planned orbit for Kuiper’s satellites at about 600 kilometers.

“Our prototype is already delivering speeds up to 400 Mbps, and performance will continue to improve in future iterations,” the company wrote in a blog post.

The company did not disclose the full design for the customer terminal.

The FCC in July authorized Amazon’s proposal for Kuiper, which the company says it will invest more than $10 billion in to build.

Amazon’s network would begin offering service once 578 satellites are in orbit, although Project Kuiper has yet to finish its satellites’ design and begin launching. SpaceX to date has launched about 900 Starlink satellites — a fraction of the total needed for global coverage but enough to begin providing service in some areas, including in the northwest United States. In October SpaceX began a public beta test of Starlink, with service priced at $99 a month.

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