# Salyut 4

> Salyut space station launched on December 26, 1974

**Wikidata**: [Q841586](https://www.wikidata.org/wiki/Q841586)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Salyut_4)  
**Source**: https://4ort.xyz/entity/salyut-4

## Summary
Salyut 4 was a Soviet space station and space laboratory launched on December 26, 1974. Designed to remain in space for extended periods with a crew, it served as a research platform orbiting Earth until its orbital decay on February 2, 1977. It was the successor to Salyut 3 and was launched using a Proton-K carrier rocket.

## Key Facts
- **Launch Date:** December 26, 1974
- **Launch Site:** Baikonur Cosmodrome Site 81/24
- **Launch Vehicle:** Proton-K
- **Decay Date:** February 2, 1977
- **Mass:** 18,500 kilograms
- **Length:** 15.8 metres
- **Diameter:** 4.15 metres
- **Volume:** 90 cubic metres
- **Orbits Completed:** 12,444
- **Crew Capacity:** 2 passengers
- **COSPAR ID:** 1974-104A
- **Preceded By:** Salyut 3
- **Succeeded By:** Salyut 5

## FAQs
### Q: When was Salyut 4 launched?
A: Salyut 4 was launched on December 26, 1974, from the Baikonur Cosmodrome.

### Q: What rocket was used to launch Salyut 4?
A: The station was launched using a Proton-K carrier rocket.

### Q: How long did Salyut 4 remain in orbit?
A: The space station remained in orbit until February 2, 1977, completing a total of 12,444 orbits around Earth.

### Q: What was the purpose of Salyut 4?
A: Salyut 4 was a space laboratory designed for research and experiments, capable of hosting a crew.

## Why It Matters
Salyut 4 represents a critical iteration in the Soviet Union's early space station program, bridging the gap between the military-focused Salyut 3 and the subsequent Salyut 5. As a dedicated space laboratory, its primary function was research, marking a focus on scientific utility in low Earth orbit. Its specifications—a mass of 18,500 kg and a habitable volume of 90 cubic metres—provided a substantial environment for a crew of two to conduct operations.

The station's orbital parameters (an apoapsis of 355 km and periapsis of 343 km) offered a stable platform that allowed it to complete over 12,000 orbits before naturally decaying in early 1977. By successfully maintaining operations for over two years, Salyut 4 contributed valuable data on long-duration spaceflight and the viability of man-made structures in space, paving the way for future generations of modular space stations.

## Notable For
- **Research Focus:** Classified specifically as a "space laboratory" designed for research, distinct from purely military reconnaissance stations.
- **Orbital Longevity:** Completed 12,444 orbits between its launch in late 1974 and its decay in early 1977.
- **Structural Volume:** Featured an internal volume of 90 cubic metres, supporting a maximum capacity of two passengers.
- **Series Continuity:** Served as the fourth station in the Salyut programme, following Salyut 3 and preceding Salyut 5.

## Body

### Mission Overview
Salyut 4 (Russian: Салют-4) was a crewed space station launched by the Soviet Union as part of the Salyut programme. It was carried into space by a Proton-K rocket on December 26, 1974, from the Baikonur Cosmodrome (Site 81/24). The station was assigned the COSPAR ID 1974-104A. It followed the earlier Salyut 3 station and was eventually succeeded by Salyut 5 in 1976. After a period of orbital operation, the station's orbit decayed, and it re-entered the atmosphere on February 2, 1977.

### Technical Specifications
The station had a total mass of 18,500 kilograms. Structurally, it measured 15.8 metres in length with a diameter of 4.15 metres, providing a total habitable volume of 90 cubic metres. The life support and facilities were designed to accommodate a maximum capacity of two passengers.

### Orbital Parameters
Salyut 4 operated in a low Earth orbit with an inclination of 51.6 degrees. Its orbital path had an eccentricity of 0.00385, with a periapsis (lowest point) of 343 kilometres and an apoapsis (highest point) of 355 kilometres above Earth. Over its operational lifespan, the station completed 12,444 orbits.

## Schema Markup
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  "@type": "Thing",
  "name": "Salyut 4",
  "description": "Salyut space station and space laboratory launched on December 26, 1974, for the purpose of research.",
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## References

1. [Source](https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1974-104A)
2. Jonathan's Space Report
3. Freebase Data Dumps. 2013
4. [Source](https://nssdc.gsfc.nasa.gov/nmc/spacecraft/displayTrajectory.action?id=1974-104A)