# Starlink bandwidth model · BAA research note

**benjamin aaron advisors · baa.website chart companion**  
Published: 2026-09-27 · Label: design downlink capacity in orbit (Tbps), not sold customer throughput.

This note documents the assumptions behind `starlink-bandwidth.html`. Figures are a BAA reconstruction from public reports and press coverage. They are not SpaceX guidance and are not Mach33 (or any third-party) numbers.

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## What the chart measures

**Design downlink capacity in orbit** = sum over operational (or shortly after checkout) satellites of each bird’s published or implied peak design downlink rate.

It is **not**:
- sold or used customer throughput
- uplink capacity
- gateway / spectrum / terminal constrained usable bandwidth
- revenue or ARPU

Usable bandwidth is typically a fraction of design capacity because of spectrum reuse limits, gateway densification, terminal capability, weather, and demand mix. Treat the chart as an upper-bound infrastructure stock, not a service KPI.

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## Per-satellite design downlink (BAA encoding)

| Generation | Gbps / sat | Tbps / sat | Basis |
|---|---:|---:|---|
| V1 | 17 | 0.017 | Secondary consensus; early generations were not always published the same way by SpaceX |
| V1.5 | 24 | 0.024 | Implied by SpaceX “4×” language vs V2 Mini at 96 Gbps |
| V2 Mini / Optimized | 96 | 0.096 | SpaceX 2024 Progress Report (and subsequent Optimized treated as same capacity class) |
| V3 | 1,000 | 1.000 | SpaceX V3 specs as reported 2024–2026 (1 Tbps downlink / sat) |

Sources cited in chart footnotes. If a primary SpaceX filing clearly overrides a cell, update the table and bump the chart revision date.

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## Historical fleet reconstruction (approx.)

Monthly points are interpolated from year-end / mid-year anchors. Sat counts are rounded; capacity is sat count × design rate. Early V1 birds are gradually retired or deorbited in the reconstruction so totals stay plausible.

| Anchor | Approx. mix | Design capacity |
|---|---|---:|
| End 2020 | ~900 V1-class | ~15 Tbps |
| End 2021 | ~1,900 V1 / V1.5 | ~40 Tbps |
| End 2022 | ~3,300 mostly V1.5 | ~80 Tbps |
| Mid 2023 | V2 Mini begins (first flights) | climb steepens |
| End 2024 | Mixed gens; SpaceX cited ~350 Tbps cumulative launched capacity in 2024 Progress Report press coverage | ~300–350 Tbps operational design (BAA uses ~320 as year-end operational anchor) |
| Jul–Sep 2026 | V2 Mini + Optimized dominant; ~8k–11k sats mixed gens | ~700–800 Tbps (BAA present ≈ **734 Tbps** at 2026-09) |

“Operational” here means BAA’s reconstruction of on-orbit design stock after a short checkout lag, not FCC licensed maximum or cumulative launched nameplate.

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## Forecast (2026-09 → 2028-12)

Pre-V3 (Falcon-launched V2 Mini / Optimized) continues a modest rise, then flattens as Starship / V3 dominates incremental capacity.

### V3 cadence milestones (base)

- **Flight 14** (late Sep 2026): +26 V3 → +26 Tbps design when operational (optional 1–2 month checkout lag in the series).
- Later full Starship loads: up to **60 V3** → +60 Tbps design per flight (SpaceX-stated class).
- Cumulative V3 sats (base):
  - End 2026: ~50–80
  - Mid 2027: ~1,000 (management “critical mass” scale often cited around Q2 2027)
  - End 2028: ~3,000–4,000 (BAA base uses **3,500**)

### Scenarios

| Case | V3 adds vs base | End-2028 V3 sats (approx.) | End-2028 total design (chart) |
|---|---|---:|---:|
| Bear | ~1/3 | ~1,170 | **1,995 Tbps** |
| Base | 1× | ~3,500 | **4,328 Tbps** |
| Bull | ~2× | ~7,000 | **7,828 Tbps** |

Present (Sep 2026) in the encoded series: **~735 Tbps** design downlink (~9.4k sats mixed gens).

Bear / bull bands are translucent around the base line after the **actual | forecast** divider (2026-09-27).

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## Markers on the chart

- **v2 mini** · first V2 Mini capacity enters the series (mid-2023)
- **optimized** · Optimized treated as same 96 Gbps class; marker at early operational scale-up
- **v3 flight 14** · late Sep 2026 first V3 block
- **actual | forecast** · 2026-09-27

Optional callout: when base forecast crosses **10×** the Sep 2026 level (~7.3 Tbps × 10 → ~7,340 Tbps), show a “~10× today” chip. With the base end-2028 near ~4.3k Tbps, that chip may appear only on the bull path or after 2028 depending on revision; the UI still supports it.

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## Caveats

1. Design ≠ sold. Spectrum, gateways, terminals, and demand constrain usable bandwidth.
2. Sat counts are public reconstructions; deorbits, spares, and checkout lag are simplified.
3. V1 / V1.5 rates are secondary consensus, not a single SpaceX table.
4. V3 cadence is the dominant forecast uncertainty; Starship flight rate drives the band width.
5. No third-party investor deck numbers were copied into this model.

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## Estimated users from design downlink

The chart UI converts design Tbps into **capacity-implied estimated users** with two knobs:

```
estimated users = design_Tbps × 1,000,000 × usable_share / mbps_per_user
```

| Knob | Meaning |
|---|---|
| **mbps per user** | Busy-hour concurrent Mbps assumed per active subscriber (not peak advertised speed) |
| **usable share** | Fraction of design downlink treated as deliverable after gateways, spectrum, weather, terminals |

### Defaults and presets

| Preset | Mbps | Usable | Framing |
|---|---:|---:|---|
| busy hour · 3 Mbps @ 50% (default) | 3 | 50% | Common busy-hour concurrent planning |
| busy hour · 3 Mbps @ 100% | 3 | 100% | Same quality, full design stock |
| calibrated · ~60 Mbps design/sub | 60 | 100% | Matches ~design stock per disclosed sub (~12M users at Sep 2026 given ~735 Tbps) |

Notes:

- **3 Mbps** is a reasonable busy-hour concurrent planning assumption.
- Matching disclosed subscriber counts historically implies ~50–70 Mbps of **design stock per sub** (≈ full design / disclosed users). That is a different framing from busy-hour concurrent Mbps; the calibrated preset encodes it as ~60 Mbps @ 100% usable.
- Calibrated math check (Sep 2026): `735e6 / 12e6 ≈ 61.25` → rounded to **60 Mbps @ 100%**.

### Illustrative levels (BAA series)

| Point | Design Tbps | Default users (3 Mbps @ 50%) | Calibrated users (60 Mbps @ 100%) |
|---|---:|---:|---:|
| Present · Sep 2026 | ~735 | ~122.5M | ~12.3M |
| End-2028 base | ~4,328 | ~721M | ~72.1M |
| End-2028 bear | ~1,995 | ~332M | ~33.3M |
| End-2028 bull | ~7,828 | ~1.30B | ~130M |

Users are **capacity-implied estimates**, not SpaceX guidance. Design ≠ sold throughput.

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## Revision

- v1 · 2026-09-27 · Initial BAA encoding for `starlink-bandwidth.html`
- v1.1 · 2026-09-27 · Estimated users view with toggleable Mbps / usable-share assumptions