About ISSINFO

Our Mission

ISSINFO provides accurate, real-time tracking of the International Space Station, NASA's Artemis Moon missions, Tiangong, the Hubble Space Telescope and other satellites using professional-grade orbital mechanics and trajectory data. Our goal is to make space science accessible to educators, students, amateur astronomers, and anyone curious about humanity's presence in orbit and beyond.

The Science Behind the Tracker

Unlike simple coordinate lookups, ISSINFO performs continuous orbital propagation using the SGP4 (Simplified General Perturbations 4) algorithm—the same mathematical model used by NORAD and NASA for satellite tracking. We apply this to every tracked satellite (ISS, Tiangong, Hubble and more), accounting for:

• Atmospheric drag — The ISS orbits at ~400km where trace atmosphere causes gradual orbital decay
• Earth's oblateness (J2 perturbation) — Earth's equatorial bulge affects orbital precession
• Gravitational harmonics — Non-uniform mass distribution influences the trajectory
• Solar radiation pressure — Photon momentum affects large structures like ISS solar arrays

We update our Two-Line Element (TLE) data from CelesTrak multiple times daily for all tracked satellites and propagate positions at 4Hz for smooth, accurate visualization.

Artemis Mission Tracking

ISSINFO tracks NASA's Artemis deep-space missions in real time using high-resolution trajectory data from JPL Horizons, the same ephemeris system used by NASA mission planners. During active missions, we display Orion's position on an interactive trajectory map with 5-minute resolution, showing mission phases, distances from Earth and the Moon, and a full mission timeline. The trajectory data covers the complete mission profile -- from launch and Trans-Lunar Injection through Lunar Flyby and return coast to splashdown.

Who We Are

Neil Johnson — Software Engineer at Microsoft with 30 years of experience in IT, specializing in real-time data systems and distributed computing. Neil handles the backend architecture, orbital propagation engine, and infrastructure.

Leo Johnson — Astronomy student focusing on orbital mechanics, spacecraft dynamics, and space science education. Leo contributes to the scientific accuracy of the tracker and develops educational content.

We built ISSINFO as a father-son project combining software engineering expertise with astronomical knowledge. What started as a learning exercise has grown into a resource used by thousands of space enthusiasts worldwide.

Contact: info@issinfo.net

Advertising: Interested in reaching our audience of space enthusiasts? Contact us at info@issinfo.net.

Data Sources & Scientific References

• CelesTrak TLE Data — Authoritative Two-Line Element sets maintained by Dr. T.S. Kelso, providing orbital data for the ISS, Tiangong, Hubble and all tracked satellites
• go-satellite (SGP4/SDP4) — Implementation of the NORAD orbital propagation algorithms
• The Space Devs API — Astronaut biographical data and mission information
• OpenStreetMap Nominatim — Reverse geocoding for sub-satellite point location
• N2YO Satellite Tracking API — Pass predictions for ISS, Tiangong, Hubble and other satellites
• NASA ISS Program — Official mission updates and operations news
• JPL Horizons System — High-precision ephemeris data for Artemis mission trajectory tracking

Technical Implementation

• Backend: Go (Golang) for high-performance orbital calculations, multi-satellite TLE management and API serving
• Propagation: SGP4/SDP4 algorithms with TLE input from CelesTrak for ISS, Tiangong, Hubble and configurable additional satellites
• Update Rate: 4Hz position updates (250ms intervals)
• Mapping: Leaflet.js with OpenStreetMap tiles
• Visualization: Chart.js for real-time altitude and velocity graphs
• Infrastructure: Docker containers on Debian, Nginx reverse proxy

Privacy & Analytics

We are committed to protecting your privacy. ISSINFO Tracker uses Plausible Analytics, a privacy-focused, GDPR-compliant analytics service that respects your privacy.

Our Analytics Approach

• Cookie-Free: Plausible doesn't use cookies or store personal data
• No IP Tracking: Your IP address is never logged or stored
• No Cross-Site Tracking: We don't track you across other websites
• GDPR Compliant: No consent banners needed - compliant by design
• Open Source: Plausible's code is fully open source and auditable

What We Collect (via Plausible)

• Page Views: Which pages are visited and when
• Referrer Sites: Which external websites send visitors to us
• Browser Type: General browser information (Chrome, Firefox, etc.)
• Country: Approximate country location (derived from IP, but IP not stored)
• Device Type: Desktop, mobile, or tablet (for responsive design optimization)

What We DON'T Collect

• Personal Information: No names, email addresses, or contact details
• IP Addresses: Never logged or stored by us or Plausible
• User Tracking: No individual user identification or behavioral profiles
• Cookies: No tracking cookies or persistent identifiers
• Precise Location: No GPS coordinates or exact geographical data
• Personal Browsing: No detailed click tracking or interaction monitoring

Data Storage & Retention

• EU Servers: All data stored on Plausible's servers in the European Union
• Retention Period: Analytics data automatically deleted after 24 months
• Aggregated Only: All data is aggregated and cannot be traced to individuals
• No Data Sales: Your data is never sold or shared with third parties

Local Storage

ISSINFO Tracker uses your browser's localStorage (not cookies) to remember your preferences, such as which satellites you have toggled on in the live map and your last-used coordinates and satellite selection on the Next Pass page. This data stays entirely in your browser, is never sent to our servers, and you can clear it at any time through your browser settings.

Contact Us

If you have any questions about our data handling practices, your privacy rights, or want to request deletion of your data, please contact us at info@issinfo.net.

Last updated: April 5, 2026