Constellation shape

A 48-satellite mid-inclination shell, the Globalstar pattern

A 48-satellite shell at 1414 km and 52 degrees as idealised geometry: high altitude buying coverage per satellite, with a hard latitude ceiling.

48 satellites in 8 planes of 6, at roughly 1410 km and 52 degrees. The clearest illustration of altitude as a lever. Flying more than twice as high as a typical LEO shell, each satellite sees far more ground, so 48 of them cover what would otherwise need several times as many.

At latitude 45 with a 10 degree elevation mask, this shape closes: no gap at any sampled longitude, a full 1440 service minutes a day. The service band reaches 78 degrees of latitude.

Across latitudes it is uneven, as most shells are. At the equator the worst outage is continuous service; at 70 degrees it is 20 s. Move the latitude control below to walk the whole range.

Scenario

SatellitesWalker 48/8/1

Orbital planes

Altitude1410 km

Inclination52.0°

Min elevation10°

Service latitude45° N/S

Latitude only. Results are worst-cased around the whole latitude circle, so this is the band a city sits on rather than the city itself.

Walker delta 48/8/1 · 48 h window · 20 s step · worst of 8 longitudes at 45°

Worst outage

none

continuous service

Average wait

no gaps

Windows / day

one unbroken window

Service / day

1440 min

of 1440 min

Coverage

100.0%

time in view

Service timeline at your latitude

48 h · worst-case longitude at 45°

Continuous service. No gaps at this latitude.

Outage vs constellation size

Worst outageAverage wait

At 45° latitude, min elevation 10°, 1410 km / 52.0°. Log scale. Labels mark the worst outage.

Worst outage vs latitude

48 sats · 1410 km · 52.0° · min elevation 10°

Latitude sweep is sampled at 60 s steps across 4 longitudes, so it is coarser than the headline figures.

Numbers

Constellation	Planes	Worst outage	Avg wait	Windows/day	Service min/day	Coverage
3 sats	3 × 1	1.7 h	63.4 min	18.3	282	19.6%
12 sats	4 × 3	23.3 min	12.4 min	39.1	956	66.4%
22 sats	11 × 2	continuous	0	1	1440	100.0%
48 sats	8 × 6	continuous	0	1	1440	100.0%
90 sats	10 × 9	continuous	0	1	1440	100.0%
200 sats	20 × 10	continuous	0	1	1440	100.0%

Same sampling as the headline tiles: 8 longitudes, 20 s steps (40 s above 400 satellites). Every row except your own uses the automatic plane rule.

Model and assumptions

Geometry: spherical Earth (R = 6371 km), circular orbits, Walker-delta constellation with evenly spaced planes and phasing F = 1, no J2 drift or drag. Service means at least one satellite above the minimum elevation angle.
Sampling: headline numbers and the table simulate 48 h (96 h for fleets of 12 or fewer) at 20 s steps, worst-cased across 8 longitudes at your latitude. The latitude chart uses 60 s steps and 4 longitudes.
Planes: "Auto" spreads satellites across the divisor of N nearest above the square root of N, a revisit-friendly default. Real constellations may choose otherwise: a single-plane test block clusters its passes.
Fidelity: planning-grade, for sizing intuition and commercial conversations. Contractual coverage commitments need full-fidelity tooling (STK, GMAT) with real ephemerides, beam patterns and link budgets. This tool models geometry only, not capacity or link margin. Full method and validation anchors.

Altitude is the cheapest coverage there is

A satellite at 1410 km is visible above a 10 degree mask across a ground circle of 26.3 degrees of arc. Drop the same shell to 550 km and that circle shrinks to 15.0 degrees. The consequence is immediate: these 48 satellites flown at 550 km instead would give 20 s at this latitude, against the figure above.

That is why a modest fleet at high LEO can hold territory a much larger low shell would struggle with. Altitude is not free: path loss grows, radiation exposure grows, deorbit obligations get harder, and latency rises. But per satellite it is the strongest coverage lever available.

The ceiling is still hard

Altitude widens the circle; it does not change where the orbit goes. At 52 degrees inclination the service band ends at 78 degrees of latitude, and no number of satellites moves it. A mid-inclination shell is a decision to serve the populated middle of the planet and not the top of it.

Reading this shape commercially

The pattern suits services where a wait is acceptable and the terminal is not a bare handset: asset tracking, messaging, telemetry, maritime. Sizing an equivalent service today means starting from the mask the terminal actually needs, then finding the altitude that makes the fleet affordable, rather than picking a satellite count first.