Satellite Internet

Orbital Classes and Their Characteristics

Satellite internet systems are classified by orbital altitude, each with distinct latency, coverage, and cost tradeoffs:

GEO Satellite Internet

Geostationary satellites remain fixed relative to Earth's surface at 35,786 km altitude, providing continuous coverage from a single satellite. GEO has been the dominant orbit for communications satellites since the 1960s.

Viasat (ViaSat-3)

• Capacity: 1 Tbps per satellite (ViaSat-3)
• Frequency: Ka-band (30/20 GHz)
• Orbital position: 144°W (ViaSat-3 Americas)
• Coverage: Hemisphere-wide spot beams
• User data rates: 100 Mbps to 1 Gbps per terminal
• Launches: ViaSat-3 F1 (May 2023), F2 (September 2023), F3 (delayed)

HughesNet (EchoStar/Jupiter)

• Platform: EchoStar XVII, XIX, XXIII (Jupiter family)
• Frequency: Ka-band
• Capacity: ~100 Gbps per satellite
• Max download: 100 Mbps
• Coverage: North America (primary market)

Intelsat EpicNG

• Satellites: Intelsat 29e, 33e, 37e (Ku/Ka-band)
• Capacity: 60+ Gbps per satellite
• Architecture: Open, backward compatible; frequency reuse via spot beams
• Coverage: Global C-band/Ku-band legacy + high-throughput Ka

LEO Satellite Internet

LEO constellations provide dramatically lower latency than GEO by operating at 550–1,200 km altitude. The tradeoff is the need for hundreds or thousands of satellites to provide continuous global coverage, plus sophisticated satellite hand-off management.

Starlink (SpaceX)

• Active satellites: 6,000+ (as of 2026)
• Total planned: 42,000+ (Gen 2)
• Frequency: Ku-band (downlink), Ka-band (uplink)
• Orbit: 550 km (Shell 1), 540–570 km
• User terminal: Flat panel electronically-steered phased array (0.3 m aperture)
• Latency: 20–40 ms RTT
• Max data rates: 350 Mbps (Gen 1), 1 Gbps (Gen 2)
• Inter-satellite links: Optical (laser) links between satellites, approximately 10 Gbps per link for current Gen-1 satellites
• Regulatory: Multiple FCC non-geostationary satellite system (NGSO) approvals

Amazon Kuiper

• Planned satellites: 3,236 total
• Orbit: 590–630 km (Phase 1), 630–650 km (Phase 2)
• Frequency: Ka-band
• User terminals: Three variants — 7", 11", 19" flat panel phased arrays
• Target latency: ~30 ms RTT
• Capacity goal: 400 Mbps per terminal
• Status: FCC approval (2020); prototype satellites tested 2022–2023; commercial deployment begins 2025

OneWeb (Eutelsat OneWeb)

• LEO constellation: 648 satellites at 1,200 km
• Frequency: Ku-band
• Latency: ~40 ms RTT
• Services: Government, maritime, aviation, enterprise
• Integration: Eutelsat GEO fleet provides integrated GEO/LEO service

MEO: SES O3b mPOWER

O3b mPOWER (Other 3 billion) operates at 8,000 km MEO, providing a middle ground between GEO and LEO. The 11-satellite constellation delivers:

• Latency: ~150–200 ms RTT
• System capacity: 10+ Tbps total
• Services: Enterprise, maritime (cruise ships), aviation, government
• Beam flexibility: Dynamic beam allocation via on-board processing

Frequency Bands

Ground Segment

Satellite internet terminals (VSAT — Very Small Aperture Terminal) consist of:

• Antenna: 0.45 m to 2.4 m parabolic dish, or flat panel phased array (Starlink, Kuiper)
• BUC (Block Upconverter): Outdoor unit; converts IF to Ka/Ku-band for uplink
• LNB (Low-Noise Block): Outdoor unit; receives and amplifies downlink signals
• IDU (Indoor Unit): Satellite modem; handles IP traffic, routing, authentication
• Feed horn: Couples transceiver to antenna dish

Flat panel phased array terminals (Starlink, Kuiper) use electronic beam steering rather than mechanical positioning, enabling:

• No moving parts — faster pointing and tracking
• Low profile — aesthetically preferred for consumer installations
• Electronic slew — rapid satellite hand-off in LEO constellations

Signal Propagation Challenges

Rain fade is the primary impairment for Ka-band and Ku-band satellite links. Heavy rain can attenuate signals by 10–30 dB, causing outages. Mitigation techniques include:

• Adaptive Coding and Modulation (ACM): Automatically reduces modulation order (e.g., 64-QAM → QPSK) as rain attenuation increases
• Uplink power control: Increases transmit power during rain fades
• Link margin: Systems designed with 3–10 dB clear-sky margin above minimum thresholds
• Site diversity: Multiple geographically separated gateways for redundancy

Inter-Satellite Links (ISL)

LEO constellation satellites use inter-satellite links to route traffic between satellites without requiring all traffic to pass through ground gateways:

• Optical (laser) links: Used by Starlink; approximately 10 Gbps per link for current Gen-1; line-of-sight required between satellites
• Ka-band RF links: Some MEO/GEO systems use RF-based ISL
• Benefits: Reduced ground infrastructure, lower latency paths for long-distance traffic

Without ISL, all traffic between two remote users must go: user → satellite → gateway → terrestrial → gateway → satellite → user. ISL allows: user → satellite →...satellite → user.

Service Applications