# PAGEOS

> passive geodetic satellite launched by NASA in 1966

**Wikidata**: [Q2043671](https://www.wikidata.org/wiki/Q2043671)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/PAGEOS)  
**Source**: https://4ort.xyz/entity/pageos

## Summary
PAGEOS is a passive geodetic satellite launched by NASA on June 24, 1966, designed to study Earth's shape and gravity field through ground-based observations. As a non-emitting, inert satellite, it relied on reflective surfaces for tracking, contributing to advancements in satellite geodesy. Operated by NASA, it formed part of a global network for precise Earth measurements.

## Key Facts
- **Launch Date**: June 24, 1966  
- **Operator**: National Aeronautics and Space Administration (NASA)  
- **COSPAR ID**: 1966-056A  
- **Launch Vehicle**: Thor-Agena D  
- **Type**: Passive satellite (no onboard energy generation or emission)  
- **SCN Number**: 02253  
- **Launch Site**: Vandenberg Space Launch Complex 2  

## FAQs
### Q: When was PAGEOS launched?
A: PAGEOS was launched on June 24, 1966, by NASA using a Thor-Agena D rocket from Vandenberg Space Launch Complex 2.

### Q: What made PAGEOS unique?
A: Unlike active satellites, PAGEOS was entirely passive, relying on reflective surfaces for ground-based laser and optical tracking to collect geodetic data.

### Q: What was the purpose of PAGEOS?
A: Its primary mission was to study Earth's geoid (shape and gravity field) by serving as a reference point for precise measurements, aiding in mapping and understanding Earth's structure.

## Why It Matters
PAGEOS played a critical role in the development of satellite geodesy, enabling scientists to measure Earth's shape and gravitational variations with unprecedented accuracy. As a passive satellite, it demonstrated the feasibility of using inert objects for long-term tracking, paving the way for later missions like the Laser Geodynamics Satellites (LAGEOS). Its data contributed to advancements in geophysics, cartography, and our understanding of Earth's interior dynamics. Despite its simplicity, PAGEOS supported international collaboration in space-based Earth observation, highlighting the value of cooperative scientific endeavors.

## Notable For
- **Early Passive Satellite Design**: One of the first satellites to use reflective surfaces for passive tracking, influencing later geodetic missions.  
- **Long-Term Geodetic Research**: Provided data for decades, helping refine models of Earth's geoid and plate tectonics.  
- **Global Measurement Network**: Part of a worldwide effort to establish precise reference points for Earth science studies.  

## Body
### Launch and Operations
- **Launch Vehicle**: Deployed via a Thor-Agena D rocket, a U.S. orbital launch vehicle used for numerous satellite missions in the 1960s.  
- **Launch Site**: Vandenberg Space Launch Complex 2 in California, a key site for polar-orbiting satellite launches.  
- **Design**: Spherical satellite with reflective panels to maximize visibility for ground-based tracking systems.  

### Technical Specifications
- **COSPAR ID**: 1966-056A (international designation for satellite tracking).  
- **SCN Number**: 02253 (Satellite Catalog Number).  
- **Operational Role**: Served as a passive target for optical and laser ranging, requiring no onboard power or communication systems.  

### Mission Objectives
- **Geodetic Studies**: Helped measure Earth's gravitational field, crustal movements, and orbital dynamics.  
- **Technological Demonstration**: Tested the effectiveness of passive satellites for long-term geodetic research.  

### Legacy
- **Scientific Impact**: Data from PAGEOS contributed to the development of the World Geodetic System (WGS), critical for navigation and mapping.  
- **Historical Context**: Part of NASA's early efforts to use space-based assets for Earth science, laying groundwork for modern satellite constellations like GPS.

## References

1. Jonathan's Space Report
2. Freebase Data Dumps. 2013