How do I install the Sun Pointing skill?

Run npx skillmds@latest add ashfordeou/sun-pointing in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Sun Pointing safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Sun Pointing?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Sun Pointing free to use?

Yes. Installing skills from SkillMD is free. This skill is licensed under Apache-2.

Who published Sun Pointing?

ashfordeOU (@ashfordeou) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Sun Pointing by ashfordeou — Agent Skill

Name: Sun Pointing
Author: ashfordeOU

Sun Pointing

Use when you must evaluate spacecraft sun pointing for the ADCS safe hold: compute the angle between the sun vector and the pointing axis, check it against the pointing tolerance, estimate the solar illumination factor at the sun angle, and size the slew rate to acquire the sun. Produces the sun pointing angle, the safe hold verdict, the illumination factor, and the required slew rate that gate sun acquisition. Trigger: sun pointing, safe hold, sun acquisition, solar illumination, slew rate.

ashfordeOU 5b4e19f 3 files · 8.2 KB Updated Sep 17, 2026

File contents

Spacecraft Sun Pointing (space-systems/adcs/sun-pointing)

Use when the task is spacecraft sun pointing for the ADCS safe hold: sun vector to pointing axis angle, tolerance checks, illumination, and sun acquisition slew sizing.

Domain quick reference

Units: vectors are dimensionless unit vectors; angles are in RADIANS; time is in seconds; slew rate is in rad/s; the solar illumination factor is dimensionless, = max(0, cos(angle)).
Sun pointing angle: acos of the clamped cosine between the sun direction vector and the spacecraft pointing axis, in radians.
Safe hold: the sun pointing angle must stay within the pointing tolerance for the sun acquisition phase.
Solar illumination factor: 1.0 at zero angle, 0.5 at 60 degrees, and 0 at or beyond 90 degrees (cosine limit).
Sun acquisition slew: required_slew_rate = angle / time, rad/s.
Sun pointing geometry follows ECSS-E-ST-60 ADCS practice.

Workflow

Collect the sun direction vector and the spacecraft pointing axis.
Compute the angle with sun_pointing_angle.
Check the angle with pointing_within_tolerance.
Estimate illumination with solar_illumination_factor.
Size the acquisition maneuver with required_slew_rate.
Gate the safe hold on the tolerance verdict.

Pitfalls

Passing angles in degrees to radian-based functions.
Zero-norm sun vector (uninitialized ephemeris) raising ValueError.
Demanding illumination beyond the cosine limit: the factor cannot exceed 1.0 at zero angle and is zero at 90 degrees and beyond.

Behavior contract (gate 3)

The sun pointing angle, tolerance, illumination, and slew logic is exercised by the gate 3 contract test: scripts/test_sun_pointing.py against scripts/sun_pointing_logic.py (stdlib unittest, offline). Run: python3 scripts/test_sun_pointing.py

Compliance

Standards referenced, not reproduced: ECSS-E-ST-60 text is copyright ESA; the sun pointing geometry here is common ADCS methodology, summary-only per standards-map.yaml (ecss is a free ESA download).
compliance: STANDARDS-REF, gated: false.

---name: sun-pointingdescription: Use when you must evaluate spacecraft sun pointing for the ADCS safe hold: compute the angle between the sun vector and the pointing axis, check it against the pointing tolerance, estimate the solar illumination factor at the sun angle, and size the slew rate to acquire the sun. Produces the sun pointing angle, the safe hold verdict, the illumination factor, and the required slew rate that gate sun acquisition. Trigger: sun pointing, safe hold, sun acquisition, solar illumination, slew rate.license: Apache-2.0---# Spacecraft Sun Pointing (space-systems/adcs/sun-pointing)Use when the task is spacecraft sun pointing for the ADCS safe hold:sun vector to pointing axis angle, tolerance checks, illumination,and sun acquisition slew sizing.## Domain quick reference- Units: vectors are dimensionless unit vectors; angles are in RADIANS; time is in seconds; slew rate is in rad/s; the solar illumination factor is dimensionless, = max(0, cos(angle)).- Sun pointing angle: acos of the clamped cosine between the sun direction vector and the spacecraft pointing axis, in radians.- Safe hold: the sun pointing angle must stay within the pointing tolerance for the sun acquisition phase.- Solar illumination factor: 1.0 at zero angle, 0.5 at 60 degrees, and 0 at or beyond 90 degrees (cosine limit).- Sun acquisition slew: required_slew_rate = angle / time, rad/s.- Sun pointing geometry follows ECSS-E-ST-60 ADCS practice.## Workflow1. Collect the sun direction vector and the spacecraft pointing axis.2. Compute the angle with sun_pointing_angle.3. Check the angle with pointing_within_tolerance.4. Estimate illumination with solar_illumination_factor.5. Size the acquisition maneuver with required_slew_rate.6. Gate the safe hold on the tolerance verdict.## Pitfalls- Passing angles in degrees to radian-based functions.- Zero-norm sun vector (uninitialized ephemeris) raising ValueError.- Demanding illumination beyond the cosine limit: the factor cannot exceed 1.0 at zero angle and is zero at 90 degrees and beyond.## Behavior contract (gate 3)The sun pointing angle, tolerance, illumination, and slew logic isexercised by the gate 3 contract test:scripts/test_sun_pointing.py against scripts/sun_pointing_logic.py(stdlib unittest, offline). Run:python3 scripts/test_sun_pointing.py## Compliance- Standards referenced, not reproduced: ECSS-E-ST-60 text is copyright ESA; the sun pointing geometry here is common ADCS methodology, summary-only per standards-map.yaml (ecss is a free ESA download).- compliance: STANDARDS-REF, gated: false.

Frequently asked questions