# MagSat

> joint NASA and USGS satellite for studying Earth's magnetic field

**Wikidata**: [Q54208](https://www.wikidata.org/wiki/Q54208)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Explorer_61)  
**Source**: https://4ort.xyz/entity/magsat

## Summary  
MagSat, also known as Explorer 61, was a joint NASA‑USGS Earth‑observation satellite launched on 30 October 1979 to map and study Earth’s magnetic field. It operated for less than a year before re‑entering the atmosphere on 11 June 1980.

## Key Facts  
- **Launch date:** 30 October 1979【source】  
- **Launch vehicle:** Scout G‑1 solid‑propellant rocket【source】  
- **Launch site:** Vandenberg Space Launch Complex 5【source】  
- **COSPAR ID:** 1979‑094A【source】  
- **Mission type:** Earth observation satellite focused on geomagnetic measurements【source】  
- **Operating agencies:** NASA (National Aeronautics and Space Administration) and USGS (U.S. Geological Survey)【source】  
- **Mission duration:** ~7 months; atmospheric entry on 11 June 1980【source】  
- **Alternate names:** Magnetic Field Satellite, AEM‑3, Applications Explorer Mission‑3, Explorer 61【source】  
- **Wikidata entity code:** 11604 (Wolfram Language Entity)【source】  

## FAQs  
### Q: What was the primary purpose of MagSat?  
A: MagSat was designed to collect high‑resolution data on Earth’s magnetic field, improving scientific understanding of geomagnetic processes.  

### Q: When and how did MagSat end its mission?  
A: The satellite re‑entered Earth’s atmosphere on 11 June 1980, ending its mission after roughly seven months in orbit.  

### Q: Which launch vehicle and site were used for MagSat?  
A: MagSat was launched aboard a Scout G‑1 rocket from Vandenberg Space Launch Complex 5 on 30 October 1979.  

## Why It Matters  
MagSat represented a pivotal collaboration between NASA and the U.S. Geological Survey, uniting space‑flight expertise with terrestrial geoscience to produce the first dedicated, high‑precision magnetic field measurements from orbit. By mapping the planet’s magnetic environment with unprecedented detail, the mission supplied critical baseline data for models of the Earth’s magnetosphere, ionosphere, and core dynamics. These observations helped refine navigation systems, improve space‑weather forecasting, and deepen scientific insight into how the magnetic field shields the planet from solar radiation. Although its operational life was brief, the quality of MagSat’s data set a new standard for geomagnetic research and informed the design of subsequent missions such as the Dynamics Explorer series, cementing its legacy in Earth‑science satellite history.

## Notable For  
- First joint NASA‑USGS satellite dedicated to magnetic field studies.  
- Utilized the reliable, low‑cost Scout G‑1 launch vehicle for a scientific payload.  
- Delivered high‑resolution geomagnetic data that became a reference for later missions.  
- Completed a full mission cycle—from launch to atmospheric re‑entry—within a single year.  

## Body  

### Overview  
MagSat (Explorer 61) was an Earth observation satellite classified under the “Earth observation satellite” instance type. Its primary scientific goal was to map the Earth’s magnetic field with high precision.

### Mission Objectives  
- Record vector magnetic field measurements.  
- Support geophysical research on the Earth’s core and magnetosphere.  
- Provide data for improving navigation and space‑weather models.

### Launch Details  
- **Date:** 30 Oct 1979.  
- **Vehicle:** Scout G‑1 solid‑propellant launch vehicle.  
- **Site:** Vandenberg Space Launch Complex 5, California.  
- **COSPAR ID:** 1979‑094A.  

### Orbit and Decay  
- Entered a low‑Earth orbit suitable for magnetic field sampling.  
- Atmospheric entry occurred on 11 June 1980, marking the end of the mission.

### Legacy and Impact  
- Data contributed to the calibration of geomagnetic models used today.  
- Served as a technological and scientific precursor to the Dynamics Explorer series.  

### Related Missions  
- Preceded and succeeded by **Dynamics Explorer 1**, another NASA geomagnetic satellite, highlighting a continuity of Earth‑magnetic research in the late 1970s and early 1980s.  

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*All information is drawn from the provided source material.*

## References

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