# Progress 4

> Soviet uncrewed Progress cargo spacecraft

**Wikidata**: [Q10639651](https://www.wikidata.org/wiki/Q10639651)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Progress_4)  
**Source**: https://4ort.xyz/entity/progress-4

## Summary
Progress 4 is a Soviet uncrewed cargo spacecraft, part of the Progress 7K-TG series, designed to resupply space stations. Launched on October 3, 1978, it delivered essential supplies to the Salyut 6 space station. It was launched using a Soyuz-U rocket from Gagarin's Start launch site.

## Key Facts
- **Launch Date**: October 3, 1978
- **COSPAR ID**: 1978-090A
- **Spacecraft Number (SCN)**: 11040
- **Instance Of**: Progress 7K-TG class spacecraft
- **Launch Vehicle**: Soyuz-U
- **Launch Site**: Gagarin's Start
- **Mission Type**: Uncrewed cargo resupply to space stations
- **Operator**: Soviet Union
- **Wikipedia Languages**: Greek (el), English (en), Swedish (sv)

## FAQs
### Q: What was the purpose of Progress 4?
A: Progress 4 was an uncrewed cargo spacecraft used to deliver supplies such as food, water, fuel, and equipment to the Salyut 6 space station. Its mission supported long-duration human spaceflight operations.

### Q: When was Progress 4 launched?
A: Progress 4 was launched on October 3, 1978. The launch occurred at Gagarin's Start using a Soyuz-U rocket.

### Q: Which space station did Progress 4 supply?
A: Progress 4 supplied the Salyut 6 space station, which was part of the Soviet Union’s orbital station program. These missions were crucial for sustaining crewed operations aboard the station.

## Why It Matters
Progress 4 represents a key milestone in the history of space logistics and support systems. As part of the Progress 7K-TG series, it played a vital role in enabling extended stays aboard the Salyut 6 space station by delivering critical resources without requiring a crewed mission. This model became foundational for future international space station programs, including Mir and the International Space Station (ISS). The success of Progress 4 demonstrated the viability of automated cargo delivery systems—a cornerstone of modern space exploration infrastructure.

## Notable For
- One of the early successful uncrewed cargo resupply missions to a space station
- First use of standardized docking systems with Salyut-class stations
- Demonstrated reliable performance of the Progress 7K-TG design
- Enabled sustained occupation of Salyut 6 through regular logistical support
- Part of the lineage leading to today’s ISS Progress vehicles

## Body
### Mission Overview
Progress 4 was the fourth spacecraft in the Progress 7K-TG series developed by the Soviet Union. It functioned as an uncrewed cargo vehicle intended to transport supplies to orbiting space stations.

### Launch Details
The spacecraft was launched on **October 3, 1978**, from **Gagarin's Start** launch complex. It utilized the **Soyuz-U** variant of the Soyuz rocket family, known for its reliability in supporting both crewed and uncrewed missions during the late 20th century.

### Technical Classification
- **Class**: Progress 7K-TG
- **SCN (Spacecraft Number)**: 11040
- **COSPAR ID**: 1978-090A
- **Instance Of**: Cargo spacecraft

### Operational Role
Progress 4 docked with the **Salyut 6** space station, providing necessary consumables and materials to support ongoing crew activities. Missions like this enabled continuous habitation of Soviet space stations throughout the 1970s and beyond.

### Legacy
This mission contributed to establishing proven protocols for automated cargo transportation in low Earth orbit—practices later adopted globally in support of the International Space Station.

## References

1. Jonathan's Space Report