HelioSPICE vs MCP Ephemeris
A side-by-side look at the HelioSPICE and MCP Ephemeris MCP servers: transport, auth, tools, quality signals, and the config to install either one in Claude, Cursor, Windsurf or VS Code.
Verdict: choose HelioSPICE for aerospace & astrodynamics work as a local process; choose MCP Ephemeris for aerospace & astrodynamics as a local process. You can also run both side by side in one mcpServers block.
Which MCP server should you choose?
Choose HelioSPICE when
- You need dedicated capabilities in the Aerospace & Astrodynamics domain.
- You prefer a local stdio subprocess transport.
- You have the keys it needs:
XHELIO_SPICE_KERNEL_DIR. - You want tools like
get_ephemeris, compute_distance, transform_coordinates.
Choose MCP Ephemeris when
- You need dedicated capabilities in the Aerospace & Astrodynamics domain.
- You prefer a local stdio subprocess transport.
- You want tools like
get_planet_positions, get_moon_phase, get_current_sky.
Feature & specification comparison
Rows where the two servers differ are marked.
| Spec | ||
|---|---|---|
| Category | Aerospace & Astrodynamics | Aerospace & Astrodynamics |
| Quality signal | 47/100 · Fair | 53/100 · Good |
| Install command | Confirmed | Confirmed |
| Transport | Local subprocess (stdio) | Local subprocess (stdio) |
| Auth | Not declared | Not declared |
| Pricing | Not declared | Not declared |
| Required env vars | XHELIO_SPICE_KERNEL_DIR | None listed |
| Verified owner | Community listing | Community listing |
| GitHub stars | 0 | 0 |
| Directory activity | 0 views 0 installs 0 upvotes | 0 views 0 installs 0 upvotes |
| Tools | 6 | 19 |
| Full listing | View HelioSPICE | View MCP Ephemeris |
Tools & capabilities
HelioSPICE tools 6
get_ephemerisPosition/velocity — single time (inline) or timeseries (CSV)compute_distanceDistance between two bodiestransform_coordinatesCoordinate frame transformlist_spice_missionsSupported missionslist_coordinate_framesAvailable frames with descriptionsmanage_kernelsKernel cache management
MCP Ephemeris tools 19
get_planet_positionsecliptic positions of all bodies (sign, degree, retro)get_moon_phasemoon phase, illumination %, descriptionget_current_skythe sky right now (current transits) for a placeget_aspectsgrid of major + minor aspects between bodiesget_natal_chartfull chart: houses, aspects, ASC/MC, moon phase, Hermetic Lotsget_transitstransit→natal aspects, sorted by orbget_synastryinter-chart aspects + harmony/tension summaryget_composite_chartmidpoint composite chartget_secondary_progressionsprogressed positions ("a day for a year")get_solar_returninstant + chart of the solar returnget_lunar_returninstant + chart of the next lunar returnget_ingressessign-change dates (retrograde-robust)- +7 more on the listing page
Ready-to-paste client configs
Paste either block (or both) into your client config, e.g. claude_desktop_config.json or ~/.cursor/mcp.json. We only show a config when the install command is confirmed.
HelioSPICE
{
"mcpServers": {
"heliospice": {
"command": "uvx",
"args": [
"xhelio-spice"
],
"env": {
"XHELIO_SPICE_KERNEL_DIR": "YOUR_XHELIO_SPICE_KERNEL_DIR_HERE"
}
}
}
}
MCP Ephemeris
{
"mcpServers": {
"mcp-ephemeris": {
"command": "npx",
"args": [
"-y",
"@cosmosos/mcp-ephemeris"
]
}
}
}
Frequently asked questions
HelioSPICE is categorized under Aerospace & Astrodynamics and uses a local stdio subprocess. MCP Ephemeris belongs to Aerospace & Astrodynamics and uses a local stdio subprocess. Pick HelioSPICE for aerospace & astrodynamics work and MCP Ephemeris for aerospace & astrodynamics.
Copy the mcpServers block from the config section on this page into your client's config (for example claude_desktop_config.json or ~/.cursor/mcp.json), then fully restart the client.
HelioSPICE has no declared pricing — check the project's own site. MCP Ephemeris has no declared pricing — check the project's own site. If a server needs environment variables such as API keys, define them under the env key in your client's MCP config.
Yes. MCP clients support multiple servers: add heliospice and mcp-ephemeris as separate keys in the same mcpServers object, and your assistant will call tools from either one.
On AllMCPs, HelioSPICE has a quality signal of 47/100 (Fair) with 0 views, 0 installs and 0 GitHub stars. MCP Ephemeris has 53/100 (Good) with 0 views, 0 installs and 0 GitHub stars.