# OSO 4

> solar space observatory

**Wikidata**: [Q16325216](https://www.wikidata.org/wiki/Q16325216)  
**Source**: https://4ort.xyz/entity/oso-4

## Summary
OSO 4 (Orbiting Solar Observatory 4) is an American solar space observatory launched in 1967 to study the Sun from Earth's orbit. Operated by NASA, it was the fourth satellite in the Orbiting Solar Observatory series and functioned as an artificial satellite for over 14 years.

## Key Facts
- **Full Name:** Orbiting Solar Observatory 4 (also known as OSO D)
- **Launch Date:** October 18, 1967
- **Launch Vehicle:** Thor-Delta expendable launch system
- **Operator:** National Aeronautics and Space Administration (NASA)
- **Manufacturer:** Ball Aerospace & Technologies
- **Mass:** 605 kilograms
- **Launch Site:** Cape Canaveral Space Launch Complex 17
- **Orbit Decay Date:** June 15, 1982 (atmospheric entry)
- **Classification:** Artificial satellite / Solar space observatory
- **Identification:** COSPAR ID 1967-100A; SCN 03000

## FAQs
### Q: What was the purpose of OSO 4?
A: OSO 4 was designed as a solar space observatory to monitor and study solar phenomena from an orbital vantage point. It was part of a dedicated series of American satellites known as the Orbiting Solar Observatory program.

### Q: Who built and operated OSO 4?
A: The satellite was manufactured by Ball Aerospace & Technologies and was operated by NASA. It was launched using an American Thor-Delta rocket.

### Q: How long did OSO 4 remain in orbit?
A: OSO 4 remained in space for nearly 15 years. It was launched on October 18, 1967, and eventually underwent atmospheric entry and orbit decay on June 15, 1982.

### Q: Which missions preceded and followed OSO 4?
A: OSO 4 was preceded by the OSO 3 mission and was succeeded by the OSO 5 mission within the Orbiting Solar Observatory series.

## Why It Matters
OSO 4 was a critical component of the United States' early efforts to conduct long-term solar observation from space. By operating as an artificial satellite outside the interference of Earth's atmosphere, it provided a platform for consistent solar data collection. Its mission was part of the broader Orbiting Solar Observatory series, which established a foundational understanding of solar physics during the late 1960s and 1970s. The satellite's longevity—spanning from its 1967 launch to its 1982 reentry—demonstrated the durability of early NASA observatory designs and the reliability of the Thor-Delta launch system and Ball Aerospace manufacturing.

## Notable For
- **Extended Mission Life:** Remained in orbit for over 14 years before its atmospheric entry in 1982.
- **Series Integration:** Served as the direct successor to OSO 3 and the predecessor to OSO 5.
- **Launch Heritage:** Launched from the historic Cape Canaveral Space Launch Complex 17.
- **Technical Identification:** Cataloged under SCN 03000 and COSPAR ID 1967-100A.

## Body
### Mission Overview
OSO 4, also referred to as OSO D, was a specialized artificial satellite designed for solar research. It was part of the Orbiting Solar Observatory (OSO) program, a series of American spacecraft dedicated to observing the Sun.

### Technical Specifications
The spacecraft had a total mass of 605 kilograms. It was manufactured by Ball Aerospace & Technologies and managed by the National Aeronautics and Space Administration (NASA). The satellite is identified in international registries by the COSPAR ID 1967-100A and the Satellite Catalog Number 03000.

### Launch and Deployment
The observatory was launched on October 18, 1967. The mission utilized the Thor-Delta expendable launch system, an American rocket series. The launch took place at Cape Canaveral Space Launch Complex 17. 

### Orbital History and Decay
Following its launch, OSO 4 successfully entered orbit to conduct its scientific mission. It followed the OSO 3 mission in the series sequence. The satellite remained in orbit until June 15, 1982, at which point it experienced atmospheric entry and orbit decay. It was succeeded in the program by OSO 5.

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  "name": "OSO 4",
  "description": "An American solar space observatory and artificial satellite launched in 1967 as part of the Orbiting Solar Observatory series.",
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## References

1. Jonathan's Space Report
2. [Source](https://nssdc.gsfc.nasa.gov/nmc/spacecraft/displayTrajectory.action?id=1967-100A)
3. [Source](https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1967-100A)