Coverage. Modelled, method published
Every engineer models this in an afternoon. Here are our numbers, with the method attached.
A pass figure that does not survive independent checking costs more than it earns. So we publish ours, we publish how we got them, and we publish where we lose.
- Blönduós, contact time
- 102 min a day
- Passes a day
- 11
- Against a 40°N station
- 2.3×
- Against Svalbard
- ~70%
Baseline case
Daily visibility for a 700km sun-synchronous satellite at 98.2° inclination, 5° elevation mask.
| Station | Latitude | Passes / day | Contact min / day | vs 40°N |
|---|---|---|---|---|
| Svalbard | 78.23°N | 15 | 141 | 3.2× |
| Tromsø | 69.66°N | 11 | 110 | 2.5× |
| Esrange | 67.88°N | 11 | 107 | 2.4× |
| Blönduós | 65.65°N | 11 | 102 | 2.3× |
| Reykjanes | 63.97°N | 11 | 97 | 2.2× |
| Mid-latitude reference | 40.00°N | 5 | 45 | 1.0× |
Method. Numerical propagation of a circular sun-synchronous orbit in an Earth-fixed frame, with J2 nodal regression, 2s steps over 24 hours, counting contiguous intervals above the elevation mask. The same model reproduces the property KSAT publishes for Svalbard — that a station at that latitude sees essentially every revolution of a polar LEO above 500km. That agreement is the only reason we consider our own numbers worth publishing. The full method note and the sensitivity cases below are in the site data pack; we expect you to reproduce them rather than take them from us.
Sensitivity
Pass counts are altitude- and mask-dependent, and quoting a single number without the assumptions is how these figures get misused. Blönduós across the range:
| Case | Passes | Min / day |
|---|---|---|
| 500 km, 5° mask | 10 | 71 |
| 700 km, 5° mask | 11 | 102 |
| 700 km, 10° mask | 10 | 69 |
| Station | Max elevation |
|---|---|
| Reykjanes | 17.7° |
| Blönduós | 16.0° |
| Tromsø | 11.8° |
| Svalbard | 3.1° |
Iceland is marginal but workable for geostationary and considerably better than the higher-latitude Nordic sites for mid-inclination orbits. It is the one place where the geometry genuinely favours us over Svalbard.
What a second site does not buy. Blönduós and Reykjanes are 217km apart, against a visibility radius of roughly 2,350km for a 700km orbit. Their pass sets are effectively identical. A second site buys weather, power and utility diversity — real value, and a different kind of value from additional contact time. It is not capacity, and it is not priced as capacity.
Next step
Take the model apart.
The method note, the sensitivity cases and the propagation assumptions go out on request. If your team reproduces it and gets a different answer, tell us — we would sooner correct a number than defend one.