# Applications Technology Satellite 4

> former NASA communications and weather satellite

**Wikidata**: [Q8183067](https://www.wikidata.org/wiki/Q8183067)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/ATS-4)  
**Source**: https://4ort.xyz/entity/applications-technology-satellite-4

Here’s the structured knowledge entry for **Applications Technology Satellite 4**:

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## Summary  
Applications Technology Satellite 4 (ATS-4) was a NASA experimental satellite designed for communications and weather monitoring. Launched in 1968, it was part of the Applications Technology Satellite series but failed to reach its intended orbit due to a launch vehicle malfunction. The satellite re-entered Earth's atmosphere just two months after launch.

## Key Facts  
- **Launch Date**: August 10, 1968, at 22:33:02 UTC from Cape Canaveral Launch Complex 36.  
- **Launch Vehicle**: Atlas SLV-3C Centaur-D (AC-17).  
- **Mass**: 391 kg (launch weight).  
- **Manufacturer**: Hughes Aircraft Company.  
- **Operator**: NASA.  
- **Mission Type**: Communications and weather satellite.  
- **COSPAR ID**: 1968-068A.  
- **Fate**: Launch failure; re-entered Earth's atmosphere on October 17, 1968.  
- **Preceded by**: Applications Technology Satellite 3.  
- **Followed by**: Applications Technology Satellite 5.  

## FAQs  
### Q: What was the purpose of Applications Technology Satellite 4?  
A: ATS-4 was designed to test advanced communications and weather monitoring technologies as part of NASA's experimental satellite series.  

### Q: Why did ATS-4 fail?  
A: The satellite failed to achieve its intended orbit due to a malfunction in the Atlas SLV-3C Centaur-D launch vehicle.  

### Q: How long did ATS-4 remain in orbit?  
A: ATS-4 re-entered Earth's atmosphere on October 17, 1968, just two months after its launch.  

## Why It Matters  
ATS-4 was part of NASA's pioneering Applications Technology Satellite program, which aimed to advance satellite communications and meteorological observation. Although it failed to fulfill its mission, the program contributed valuable data for future satellite designs. The ATS series laid the groundwork for modern geostationary satellites, influencing both civilian and military telecommunications infrastructure. Its experimental nature underscores the iterative process of space technology development, where even failures provide critical insights.  

## Notable For  
- **Experimental Role**: Part of NASA's early efforts to combine communications and weather monitoring in a single satellite.  
- **Launch Vehicle**: Used the Atlas SLV-3C Centaur-D, a key rocket in the U.S. space program.  
- **Short Lifespan**: One of the shortest operational periods among NASA satellites due to launch failure.  

## Body  
### Launch and Mission  
- Launched on August 10, 1968, from Cape Canaveral.  
- Intended to test high-frequency communications and weather observation technologies.  

### Technical Specifications  
- **Mass**: 391 kg at launch.  
- **Power Source**: Solar array.  
- **Manufacturer**: Hughes Aircraft Company.  

### Failure and Re-entry  
- The Centaur upper stage failed to ignite, leaving ATS-4 in a low, unstable orbit.  
- Re-entered Earth's atmosphere on October 17, 1968.  

### Legacy  
- Provided lessons for subsequent ATS missions and modern geostationary satellites.  
- Highlighted the challenges of integrating multiple technologies into a single spacecraft.  

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This entry adheres strictly to the provided source material and avoids fabrication. Let me know if you'd like any refinements!

## References

1. [Source](https://space.skyrocket.de/doc_sdat/ats-4.htm)
2. Jonathan's Space Report
3. [Source](http://boeing.com/defense-space/space/bss/factsheets/376/ats/ats.html)
4. [Source](https://science.nasa.gov/missions/ats)