# Kosmos 638

> USSR spacecraft

**Wikidata**: [Q1392129](https://www.wikidata.org/wiki/Q1392129)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Kosmos_638)  
**Source**: https://4ort.xyz/entity/kosmos-638

## Summary
Kosmos 638 was an uncrewed spaceflight of the Soviet space program launched on April 3, 1974. It utilized the Soyuz 7K-TM spacecraft, a second-generation variant of the Soyuz vessel, which remained in low Earth orbit for over nine days before landing on April 13, 1974. The mission is designated under the COSPAR ID 1974-018A.

## Key Facts
- **Classification:** Uncrewed spaceflight using the Soyuz 7K-TM spacecraft class.
- **Launch Date:** April 3, 1974, at 07:30:00.
- **Landing Date:** April 13, 1974.
- **Mission Duration:** 14,228 minutes.
- **Launch Vehicle:** Soyuz-U rocket.
- **Launch Site:** Baikonur Cosmodrome (Site 31).
- **Spacecraft Mass:** 6,570 kilograms at takeoff.
- **Orbital Parameters:** Low Earth orbit with a period of 89.4 minutes and an inclination of 51.8 degrees.
- **Operator:** Soviet space program.
- **Program Affiliation:** Part of the Soyuz programme.
- **Identifiers:** COSPAR ID 1974-018A; SCN 07234.

## FAQs
### Q: What type of spacecraft was Kosmos 638?
A: Kosmos 638 was a Soyuz 7K-TM spacecraft, a second-generation variant of the Soyuz series used between 1974 and 1976. It operated as an uncrewed spaceflight.

### Q: When was Kosmos 638 launched and how long did it stay in orbit?
A: The spacecraft launched on April 3, 1974, and remained in orbit for 14,228 minutes (approximately 9.9 days) before landing on April 13, 1974.

### Q: What rocket was used to launch Kosmos 638?
A: Kosmos 638 was launched using a Soyuz-U rocket, a universal design variant of the Soyuz rocket family.

## Why It Matters
Kosmos 638 serves as a specific data point in the history of the Soviet Soyuz programme, representing the application of the 7K-TM spacecraft variant during the early 1970s. As an uncrewed mission, it contributed to the operational history of the Soyuz-U launch vehicle and the testing of spacecraft systems in low Earth orbit. Weighing 6,570 kilograms at takeoff, it demonstrates the mass capabilities and orbital parameters—specifically the 51.8-degree inclination—standard for Soviet space operations of this era. By logging over 14,000 minutes of flight time, the mission provided valuable flight heritage for the 7K-TM design, which was active during a pivotal period of space exploration (1974–1976).

## Notable For
- Being an uncrewed flight of the **Soyuz 7K-TM** variant.
- A mission duration of **14,228 minutes**, lasting nearly 10 days.
- Launching from **Baikonur Cosmodrome Site 31**, a specific launch complex within the Cosmodrome.
- Use of the **Soyuz-U** universal rocket design.
- Maintaining a low Earth orbit with a specific **inclination of 51.8 degrees**.

## Body
### Mission Profile
Kosmos 638 was an instance of an uncrewed spaceflight launched by the Soviet space program on April 3, 1974. The mission lifted off from the Baikonur Cosmodrome Site 31 at 07:30:00. The launch was executed using a Soyuz-U rocket. The spacecraft remained in orbit for a total of 14,228 minutes before successfully landing on April 13, 1974.

### Spacecraft Specifications
The vessel used for this mission was the **Soyuz 7K-TM**, a variant of the 2nd-generation Soyuz spacecraft. The spacecraft had a total mass of 6,570 kilograms at takeoff. It was part of the broader Soyuz programme.

### Orbital Characteristics
Kosmos 638 operated in a low Earth orbit. The orbital period was recorded as 89.4 minutes relative to Earth. The orbital inclination was 51.8 degrees.

### Identifiers and Cataloging
The mission is cataloged under the satellite catalog number (SCN) 07234 and the COSPAR ID 1974-018A. In external databases, it is referenced via the Freebase ID /m/0b7jzk.

## References

1. Jonathan's Space Report
2. Freebase Data Dumps. 2013