HelioSPICE

xhelio-spice

Spacecraft ephemeris made easy — auto-managed SPICE kernels for heliophysics missions.

xhelio-spice wraps SpiceyPy with automatic kernel download, caching, and loading. Ask for a spacecraft position and xhelio-spice handles the rest: downloading the right NAIF kernels, loading them in the correct order, and returning results as Python dicts or pandas DataFrames.

Installation

pip install xhelio-spice

For MCP server support (Claude Desktop, Claude Code, Cursor, etc.):

pip install xhelio-spice[mcp]

Quick Start

from xhelio_spice import get_position, get_trajectory

Where is Parker Solar Probe right now?

pos = get_position("PSP", observer="SUN", time="2024-01-15", frame="ECLIPJ2000") print(f"PSP is {pos['r_au']:.3f} AU from the Sun")

Get a month of trajectory data as a DataFrame

df = get_trajectory( "PSP", observer="SUN", time_start="2024-01-01", time_end="2024-01-31", step="1h", frame="ECLIPJ2000", ) print(df[["r_au"]].describe())

Kernels are automatically downloaded from NAIF on first use and cached in ~/.xhelio_spice/kernels/.

Supported Missions

With SPICE Kernels (auto-downloaded)

• PSP (Parker Solar Probe) — 2018-2030
• Solar Orbiter (SOLO) — 2020-2030
• STEREO-A — 2017-2031
• Juno — 2011-present (updated regularly)
• Voyager 1/2 — 1981-2100 / 1989-2100
• New Horizons — 2019-2030

NAIF IDs Only (no auto-download yet)

• ACE, Wind, DSCOVR, MMS (1-4) — no public SPK kernels exist
• Cassini, MAVEN — require multi-segment kernel loading (planned)
• Galileo, Pioneer 10/11, Ulysses, MESSENGER, STEREO-B

Natural Bodies

Sun, Earth, Moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto

API Reference

Position & Trajectory

from xhelio_spice import get_position, get_trajectory, get_state

Single position

pos = get_position("ACE", observer="EARTH", time="2024-06-01", frame="GSE")

Full state (position + velocity)

state = get_state("PSP", observer="SUN", time="2024-01-15", frame="ECLIPJ2000")

Trajectory timeseries (returns pandas DataFrame)

df = get_trajectory( "Cassini", observer="SATURN", time_start="2010-01-01", time_end="2010-12-31", step="6h", frame="ECLIPJ2000", include_velocity=True, )

Coordinate Transforms

from xhelio_spice import transform_vector, list_available_frames

J2000 to Ecliptic

v_ecl = transform_vector([1.0, 0.0, 0.0], "2024-01-15", "J2000", "ECLIPJ2000")

RTN transform (requires spacecraft)

v_rtn = transform_vector( [5.0, -3.0, 1.0], "2024-01-15", from_frame="ECLIPJ2000", to_frame="RTN", spacecraft="PSP", )

List all frames

print(list_available_frames())

Mission Registry

from xhelio_spice import resolve_mission, list_supported_missions

Resolve name aliases

naif_id, key = resolve_mission("Parker Solar Probe") # -> (-96, "PSP")

List all spacecraft

missions = list_supported_missions()

Kernel Management

from xhelio_spice import get_kernel_manager

km = get_kernel_manager() km.ensure_mission_kernels("PSP") # Download + load print(km.get_cache_info()) # Cache stats km.unload_all() # Free memory

Configuration

MCP Server

xhelio-spice includes an MCP server for LLM tool use:

# Run directly

xhelio-spice-mcp

Or via Python

python -m xhelio_spice.server

Claude Desktop Configuration

Add to claude_desktop_config.json:

{

"mcpServers": { "xhelio-spice": { "command": "xhelio-spice-mcp" } } }

Available MCP Tools

MCP smoke test

For a CI-safe MCP check that does not request kernel downloads, run:

uv run --extra mcp python scripts/smoke_mcp_list_tools.py --json

The smoke starts the stdio server with an isolated temporary kernel cache, runs MCP initialize + list_tools, and verifies the advertised tool names.

License

MIT