# Nimbus 4

> U.S. meteorological satellite

**Wikidata**: [Q16320350](https://www.wikidata.org/wiki/Q16320350)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Nimbus_4)  
**Source**: https://4ort.xyz/entity/nimbus-4

## Summary
Nimbus 4 was a U.S. meteorological satellite launched on April 8, 1970, as part of the Nimbus program. It served as both a weather monitoring satellite and a technology demonstration spacecraft, operated by NASA and NOAA throughout its mission.

## Key Facts
- Launched on April 8, 1970 at 08:17:56 from Vandenberg Space Launch Complex 2 East
- Had a mass of 619 kg (launch weight) and was powered by 2 spacecraft solar arrays
- Part of the Nimbus program and operated by both NASA and NOAA
- Used a Thorad-Agena D rocket (launch number 553/6231)
- Was preceded by Nimbus 3 and succeeded by Nimbus 5
- Maintained a polar orbit until atmospheric re-entry on September 30, 1980
- Manufactured by RCA Corporation with COSPAR/NSSDCA ID: 1970-025A
- Also known as "Nimbus D" with SCN number 04362

## FAQs
### Q: What was the primary purpose of Nimbus 4?
A: Nimbus 4 was designed as both a weather monitoring satellite and a technology demonstration spacecraft for the Nimbus program. It provided meteorological data while testing experimental technologies for future satellite missions.

### Q: When and how was Nimbus 4 launched?
A: Nimbus 4 was launched on April 8, 1970, at 08:17:56 from Vandenberg Space Launch Complex 2 East, aboard a Thorad-Agena D rocket with launch number 553/6231.

### Q: What happened to Nimbus 4 after its mission?
A: Nimbus 4 operated until September 30, 1980, when it re-entered Earth's atmosphere after completing its mission, having been in operation for approximately 10 years and 5 months.

### Q: Who manufactured Nimbus 4 and what was its power source?
A: Nimbus 4 was manufactured by RCA Corporation and was powered by two spacecraft solar arrays, with a launch mass of 619 kilograms.

### Q: What satellites preceded and succeeded Nimbus 4 in the Nimbus program?
A: Nimbus 4 was preceded by Nimbus 3 and succeeded by Nimbus 5 in the second-generation Nimbus program of U.S. robotic spacecraft.

## Why It Matters
Nimbus 4 represented a significant advancement in meteorological satellite technology, demonstrating systems that would later become standard in weather observation. As part of the Nimbus program, it contributed to the development of remote sensing techniques that revolutionized weather forecasting and climate monitoring. The satellite's ability to provide comprehensive atmospheric data helped improve weather prediction models and enhanced our understanding of Earth's climate systems. Its successful operation for over a decade demonstrated the durability and reliability of meteorological satellites in polar orbit, paving the way for more sophisticated environmental monitoring missions that followed.

## Notable For
- Being the fourth satellite in the Nimbus program, continuing the second-generation U.S. robotic spacecraft series
- Operating in polar orbit for approximately 10 years and 5 months before re-entering Earth's atmosphere
- Serving dual roles as both a weather satellite and technology demonstration spacecraft
- Using Thorad-Agena D rocket for launch, which was more powerful than the earlier Thor-Agena D
- Having an alias "Nimbus D" in addition to its official designation

## Body
### Basic Information
Nimbus 4 was a U.S. meteorological satellite launched on April 8, 1970, at 08:17:56 from Vandenberg Space Launch Complex 2 East. The satellite was part of the Nimbus program, which represented the second-generation of U.S. robotic spacecraft dedicated to meteorological observations. It maintained a polar orbit throughout its operational life, which lasted until September 30, 1980, when it re-entered Earth's atmosphere after approximately 10 years and 5 months of service.

### Technical Specifications
- Mass: 619 kg (launch weight)
- Power: 2 spacecraft solar arrays
- Orbit: Polar orbit
- Manufacturer: RCA Corporation
- COSPAR/NSSDCA ID: 1970-025A
- SCN: 04362

### Launch and Mission
Nimbus 4 was launched using a Thorad-Agena D rocket with launch number 553/6231. This rocket was developed by the USA and was more powerful than the earlier Thor-Agena D version. The satellite was operated jointly by NASA (National Aeronautics and Space Administration) and NOAA (National Oceanic and Atmospheric Administration).

### Program Context
As part of the Nimbus program, Nimbus 4 followed Nimbus 3 and was succeeded by Nimbus 5. It represented an important step in the evolution of meteorological satellite technology, serving both practical weather monitoring functions and demonstrating experimental technologies for future missions.

### Legacy
Nimbus 4 contributed significantly to the advancement of meteorological satellite systems and remote sensing technologies. Its successful long-duration operation in polar orbit demonstrated the feasibility of maintaining continuous Earth observation from space, which has since become fundamental to modern weather forecasting and climate monitoring.

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## References

1. [Source](https://space.skyrocket.de/doc_sdat/nimbus-4.htm)
2. Jonathan's Space Report
3. [Source](https://nssdc.gsfc.nasa.gov/earth/nimbus.html)