Can you recommend an ephemeris API for orbit prediction in a customer-facing space application?

Yes — but the “best” ephemeris API depends a lot on what you mean by orbit prediction:

• High-accuracy spacecraft ephemeris for a specific satellite/object
• General celestial ephemeris for planets/moons/asteroids
• Real-time TLE-based predictions for LEO satellites
• Customer-facing display where ease of use and reliability matter more than sub-km precision

Here are the best options by use case:

Good API options

1. JPL Horizons API

Best for: Solar system bodies, high-quality celestial ephemerides
Pros:

• Extremely authoritative
• Great for planets, moons, comets, asteroids
• Widely trusted
• Can query positions, velocities, observability data, etc.

Cons:

• Not ideal for arbitrary Earth-orbiting satellites
• More “scientific” than product-friendly
• Rate/usage constraints and integration can be a bit awkward for production apps

Use if: Your app shows planetary/astronomical positions rather than operational satellite orbit prediction.

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2. CelesTrak data + your own propagation

Best for: Satellite orbit prediction from TLEs
Pros:

• Standard, widely used TLE source
• Good for Earth orbiting satellites
• You can propagate with SGP4 in your backend

Cons:

• CelesTrak is a data source, not a polished commercial API for a customer-facing product
• TLEs have limited accuracy, especially for maneuvering or higher-drag objects
• You’ll still need to build the propagation service yourself

Use if: You want a low-cost, technically solid satellite visibility/orbit solution and can run propagation yourself.

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3. Skyfield / sgp4 (self-hosted libraries)

Best for: Precise enough satellite/astronomical calculations inside your own service
Pros:

• Very reliable libraries
• No external dependency for every request
• Full control over caching, latency, and UX
• Good for customer-facing apps if you wrap it well

Cons:

• Not an API by itself
• You must manage data updates and propagation logic

Use if: You want production control and can own the engineering.

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4. AGI / COMSPOC / analytical orbit services

Best for: Enterprise-grade orbit prediction and space operations
Pros:

• Strong for mission/operations contexts
• Better support for complex orbit determination/prediction workflows
• Often more accurate and robust than “consumer” alternatives

Cons:

• Typically expensive
• More enterprise-oriented than app-oriented
• Integration may be heavier

Use if: Your customer-facing app is part of a serious space operations product and budget is available.

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5. NASA SPICE toolkit / NAIF

Best for: High-fidelity ephemerides for spacecraft and planetary geometry
Pros:

• Industry-standard for space geometry
• Excellent accuracy and flexibility
• Good for complex mission geometry calculations

Cons:

• Not an API service out of the box
• More of a toolkit/data system than a simple hosted API
• Requires more domain expertise

Use if: You need engineering-grade ephemeris computations and are comfortable building around SPICE.

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My practical recommendation

If you need a customer-facing app with Earth satellites

Use:

• CelesTrak TLEs as your data source
• SGP4 for propagation
• Wrap it in your own backend/API

This is usually the best mix of:

• cost
• performance
• control
• acceptable accuracy for display and scheduling

If you need planetary/astronomical ephemeris

Use:

• JPL Horizons or
• SPICE if you need more control and can host it yourself

If you need enterprise orbit prediction

Consider:

• COMSPOC / AGI / specialized commercial space software providers

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Important note on accuracy

For a customer-facing app, “orbit prediction” can mean very different precision levels:

• Display only / visibility windows / pass predictions: TLE + SGP4 is usually enough
• Operational planning / maneuver-sensitive satellites: you’ll need more than TLEs
• Long-term prediction: accuracy degrades quickly for Earth-orbiting objects unless you have maintained orbital elements

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If you want a simple answer

• Planets/solar system: JPL Horizons
• Satellites: CelesTrak + SGP4
• Enterprise mission ops: AGI/COMSPOC-style commercial tooling

If you want, I can also recommend:

1. a specific hosted API you can call today, or
2. a reference architecture for building your own customer-facing orbit prediction service.