Spacecraft ephemeris made easy — auto-managed SPICE kernels for heliophysics
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.
pip install xhelio-spice
For MCP server support (Claude Desktop, Claude Code, Cursor, etc.):
pip install xhelio-spice[mcp]
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/.
Sun, Earth, Moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto
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,
)
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())
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()
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
| Method | Description |
|---|---|
XHELIO_SPICE_KERNEL_DIR env var | Override kernel cache directory |
KernelManager(kernel_dir=...) | Per-instance override |
| Default | ~/.xhelio_spice/kernels/ |
xhelio-spice includes an MCP server for LLM tool use:
# Run directly
xhelio-spice-mcp
# Or via Python
python -m xhelio_spice.server
Add to claude_desktop_config.json:
{
"mcpServers": {
"xhelio-spice": {
"command": "xhelio-spice-mcp"
}
}
}
| Tool | Description |
|---|---|
get_ephemeris | Position/velocity — single time (inline) or timeseries (CSV) |
compute_distance | Distance between two bodies |
transform_coordinates | Coordinate frame transform |
list_spice_missions | Supported missions |
list_coordinate_frames | Available frames with descriptions |
manage_kernels | Kernel cache management |
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.
MIT
Source-derived launch command. Check the maintainer’s required arguments and credentials before running:
uvx heliospiceMerge this template into ~/Library/Application Support/Claude/claude_desktop_config.json. Keep existing servers. Add any arguments, credentials, and permissions required by the maintainer; this template has not been install-tested.
{
"mcpServers": {
"io-github-huangzesen-heliospice": {
"command": "uvx",
"args": [
"heliospice"
]
}
}
}Restart Claude Desktop completely for changes to take effect. Confirm the server appears connected in the client’s tool list, then try a read-only example from its documentation.
Claude Desktop setup referenceheliospicepypiHelioSPICE works with any MCP-compatible client. Copy the config snippet from the Configuration section above and add it to the file shown for your client, then restart the application.
~/Library/Application Support/Claude/claude_desktop_config.jsonRestart Claude Desktop completely for changes to take effect.~/.cursor/mcp.jsonRestart Cursor for changes to take effect..vscode/mcp.jsonReload VS Code window for changes to take effect.~/.codeium/windsurf/mcp_config.jsonRestart Windsurf for changes to take effect..mcp.jsonSave at the project root, then start Claude Code in that project and review the MCP server approval prompt. Keep real credentials out of shared files.