`orbitforge constellation walker`

Synopsis


orbitforge constellation walker \
  --name <NAME> --planes <N> --sats-per-plane <N> \
  --altitude-km <KM> --inclination-deg <DEG> --output <PATH> [OPTIONS]

Description

Generates a Walker constellation: satellites distributed evenly across planes, and evenly within each plane, so that coverage gaps are spread rather than clustered.

The output is a constellation definition, not a trajectory. It fixes where the satellites start; simulate advances them through time.

Options

Parameter	Type	Unit	Default	Required	Description
`--name`	string	n/a	—	Yes	Constellation name, used for satellite identifiers and labels.
`--planes`	integer	count	—	Yes	Number of orbital planes.
`--sats-per-plane`	integer	count	—	Yes	Satellites per plane, evenly spaced in true anomaly.
`--altitude-km`	float	km	—	Yes	Orbit altitude above the reference ellipsoid.
`--inclination-deg`	float	deg	—	Yes	Inclination. Sets the latitude ceiling; see the warning below.
`--output`	path	n/a	—	Yes	Output constellation JSON path.
`--pattern`	enum	n/a	`delta`	No	`delta` spreads RAAN over 360 degrees; `star` spreads it over 180.
`--phasing`	integer	n/a	`1`	No	Inter-plane phasing factor F, where 0 <= F < planes.
`--raan-offset-deg`	float	deg	`0`	No	RAAN of the first plane. Rotates the whole shell without changing its geometry.
`--fov-deg`	float	deg	`45`	No	Payload field of view, used later for coverage footprints.

Worked examples

Walker Delta


orbitforge constellation walker \
  --name demo --planes 6 --sats-per-plane 10 \
  --altitude-km 550 --inclination-deg 53 --fov-deg 45 \
  --output demo.json


Generated 'demo' with 60 satellites (6 planes x 10 per plane) -> demo.json

Walker Star, near-polar


orbitforge constellation walker \
  --name star --planes 6 --sats-per-plane 8 \
  --altitude-km 800 --inclination-deg 98 --pattern star --fov-deg 40 \
  --output star.json


Generated 'star' with 48 satellites (6 planes x 8 per plane) -> star.json

An inclination of 98 degrees is retrograde and close to sun-synchronous at this altitude, which is the usual choice for Earth observation.

Delta and Star

Pattern	RAAN spread	Character
`delta`	360 degrees	Even coverage between the inclination limits. The usual choice for broadband and Earth observation
`star`	180 degrees	Planes converge over the poles. Strong polar coverage, with a seam where ascending and descending planes meet

A Star pattern concentrates planes into a half-sphere of RAAN, so ascending and descending planes counter-rotate relative to each other. Where they meet, the relative velocity between adjacent planes is at its largest, which matters if you intend to fly inter-satellite links across that seam.

Phasing

--phasing sets the offset applied to each successive plane, so that satellites in adjacent planes do not all cross the equator at the same moment:

\Delta\Omega = \frac{360^\circ}{p}, \qquad \Delta\nu = \frac{360^\circ}{s}, \qquad \text{offset per plane} = \frac{360^\circ F}{p \cdot s}

where $p$ is planes, $s$ is satellites per plane, and $F$ is the phasing factor.

The value matters. A poor choice clusters satellites at plane crossings, which both wastes coverage and creates the close approaches that conjunction screen exists to find. Screen any design whose phasing you have changed.

The inclination ceiling

Inclination sets a hard limit on the latitude that can be covered at all. A 53-degree constellation never passes over the poles, so polar ground points are never covered by any satellite in it, regardless of how many you add.

This appears in coverage output as a minimum of 0.0 percent alongside a healthy mean. See coverage and revisit.

Inclination	Reaches	Typical use
0 degrees	Equator only	Geostationary and equatorial systems
53 degrees	Up to 53 degrees latitude	Broadband, where most people live
98 degrees	Everything, retrograde	Sun-synchronous Earth observation

What the output contains

The constellation JSON holds each satellite’s identifier and initial Keplerian elements, plus the field of view. It carries no payload, mass, or RF properties, because those are supplied to the analysis commands that need them.

Satellite identifiers follow the pattern <name>-s0-p<plane>-sat<index>, for example demo-s0-p00-sat00. Error messages from later commands name satellites this way, so the identifier tells you which plane and slot failed.

orbitforge constellation walker