KuiperSat KA-1 Mission Marks Critical First Step for Amazon’s Broadband Network

Atlas V launches KA-1 mission // Photo: ULA

Tonight, April 28, 2025, United Launch Alliance (ULA) successfully launched an Atlas V 551 rocket from Space Launch Complex-41 at Cape Canaveral Space Force Station, Florida. Liftoff occurred precisely at 7:01 p.m. EDT (23:01 UTC), sending 27 operational satellites into low Earth orbit for Amazon’s Project Kuiper broadband constellation.

This mission, designated KuiperSat KA-1, will mark the first full production deployment for Amazon’s massive ~3,236-satellite network aimed at delivering affordable broadband internet worldwide. The satellites will be injected into a 630-kilometer circular orbit after multiple burns by the Centaur upper stage.

Technical Mission Details

• Rocket: Atlas V 551 (5-meter payload fairing, 5 solid rocket boosters, single-engine Centaur upper stage)

• Payload: 27 Kuiper broadband satellites

• Total Payload Mass: Estimated around 13,500 kg (~500 kg per satellite)

• Orbit: 630 km altitude, 51.9° inclination

• Mission Profile: Core stage + solid booster separation → Centaur multiple burns → Deployment of satellites in batches

The Atlas V 551 configuration, the most powerful Atlas variant available, was selected to maximize payload delivery to low Earth orbit for this heavy cluster.

About the Payload: Project Kuiper Satellites

Each Kuiper satellite is a medium-sized LEO communications platform, weighing approximately 500 kilograms. They are equipped with:

• Ka-band phased array antennas for high-throughput internet delivery

• Inter-satellite laser links for faster and more resilient network routing

• Advanced onboard propulsion for orbit maintenance and deorbiting at end-of-life

• High-efficiency solar arrays for sustained operations in LEO

These satellites are designed to operate autonomously, forming dynamic mesh networks to efficiently route internet traffic across the globe. The Kuiper system is a direct competitor to SpaceX's Starlink, but Amazon’s approach is focused on:

• High throughput

• Low latency

• Global service expansion — including remote and underserved regions

Tonight’s deployment will support system validation and early operational rollout, with commercial customer service targeted to begin later this year.

A Historic Moment for the Atlas Family

Tonight’s flight also carries historic significance for ULA’s Atlas program.

The Atlas V traces its origins to the legendary Atlas D missile of the late 1950s. Throughout its history, the Atlas family has:

• Launched America's first astronauts (Mercury program)

• Delivered spacecraft across the Solar System (Pioneer, Mariner, InSight, and more)

• Supported critical national security missions over decades

The Atlas V, introduced in 2002, became a workhorse for NASA, the DoD, and commercial satellite operators, boasting over 99 successful flights.

However, Atlas V is being phased out:

• Production has ended, with only a few launches remaining.

• ULA is shifting to the Vulcan Centaur, a fully domestic rocket using U.S.-built BE-4 engines.

• A key reason is the dependence on the Russian RD-180 engine, considered politically and strategically untenable for the future.

The Atlas legacy will soon pass to history, but its contributions to space exploration and defense will remain foundational.

Looking Ahead

For Project Kuiper, this is just the beginning. Over 80 launches across ULA, SpaceX, and Blue Origin have been contracted to deploy the full constellation within the next few years.

Meanwhile, ULA’s upcoming Vulcan Centaur rocket will assume duties for future heavy-lift missions, continuing the legacy of Atlas into a new era of American launch capability.

Tonight’s mission wasn’t just another launch — it was a handoff between generations — and a glimpse into the future of global internet access powered from orbit.