# Interkosmos 4

> former Soviet solar radiation research satellite

**Wikidata**: [Q252603](https://www.wikidata.org/wiki/Q252603)  
**Source**: https://4ort.xyz/entity/interkosmos-4

## Summary
Interkosmos 4 was a Soviet solar radiation research satellite launched on October 14, 1970. Manufactured by the Pivdenne Design Office, it was the second unit of the DS-U3-IK model and part of the broader Dnepropetrovsk Sputnik family. The satellite operated for approximately three months before decaying from orbit and entering the atmosphere on January 17, 1971.

## Key Facts
- **Classification:** Former Soviet solar radiation research satellite; instance of the DS-U3-IK model (specifically DS-U3-IK No. 2).
- **Launch Date:** October 14, 1970, at 11:29:58 UTC.
- **Launch Site:** Kapustin Yar.
- **Launch Vehicle:** Kosmos-2I (a superseded Soviet carrier rocket).
- **Mass:** 320 kilograms.
- **Operator:** Interkosmos.
- **Manufacturer:** Pivdenne Design Office.
- **Decay Date:** January 17, 1971 (atmospheric entry).
- **COSPAR ID:** 1970-084A.
- **Satellite Catalog Number:** 04580.
- **Power System:** Spacecraft solar array (equipped with 8 units).
- **Spacecraft Bus:** DS-U3.

## FAQs
### Q: What was the primary mission of Interkosmos 4?
A: Interkosmos 4 was designed for solar radiation research. It was part of the Soviet Interkosmos program, which focused on space exploration and scientific research.

### Q: When was Interkosmos 4 launched and how long did it remain in orbit?
A: The satellite was launched on October 14, 1970. It remained in orbit for a brief period, decaying and re-entering the atmosphere on January 17, 1971.

### Q: What rocket was used to launch Interkosmos 4?
A: The satellite was launched aboard a Kosmos-2I carrier rocket from the Kapustin Yar launch site.

## Why It Matters
Interkosmos 4 serves as a specific example of the Soviet Union's collaborative scientific efforts under the Interkosmos program during the Cold War. As the second satellite in the DS-U3-IK series (DS-U3-IK No. 2), it highlights the standardization of Soviet satellite technology through the Dnepropetrovsk Sputnik bus system, developed by the Pivdenne Design Office.

The satellite is significant for its specialized role in studying solar radiation, contributing to the understanding of space weather and solar physics in the early 1970s. Its launch aboard the Kosmos-2I rocket—a vehicle described in records as "superseded"—marks a transitional period in launch vehicle technology. Furthermore, the mission demonstrates the typical lifecycle of low-earth orbit scientific satellites of that era, which often had short operational lifespans before decaying, as evidenced by its re-entry roughly three months after launch.

## Notable For
- Being the second satellite of the **DS-U3-IK** model series (also known as DS-U3-IK #2).
- Operating under the **Interkosmos** program, an international space effort led by the Soviet Union.
- Utilizing the **DS-U3** spacecraft bus, a standard platform for the Dnepropetrovsk Sputnik family.
- Studying **solar radiation**, a key scientific objective for early space physics.
- Being launched by the **Kosmos-2I**, a carrier rocket noted as a superseded model in Soviet aerospace history.

## Body

### Development and Design
Interkosmos 4 was a product of the Soviet space industry, specifically manufactured by the **Pivdenne Design Office**. It belonged to the **Dnepropetrovsk Sputnik** family, a prolific series of Soviet satellites. The satellite was built on the **DS-U3** spacecraft bus and classified as an instance of the **DS-U3-IK** model.

Physically, the satellite had a mass of **320 kilograms**. It was engineered to utilize solar energy, powered by a **spacecraft solar array** comprising 8 individual units.

### Mission Profile
The satellite was launched on **October 14, 1970**, at precisely **11:29:58** UTC. The launch took place at the **Kapustin Yar** range, a major Soviet rocket launch and development site. The vehicle used to propel Interkosmos 4 into orbit was the **Kosmos-2I**, a two-stage carrier rocket derived from the R-12 and R-14 missiles, which had previously served as a workhorse for the Soviet space program but was eventually superseded.

### Operational History and Decay
The primary function of Interkosmos 4 was to conduct research on **solar radiation**. Its operational life in orbit was relatively short. According to tracking data, the mission concluded when the satellite underwent **atmospheric entry** on **January 17, 1971**.

### Identifiers and Aliases
In various databases and languages, Interkosmos 4 is referred to by several aliases, including **IK-4**, **Intercosmos 4**, and **DS-U3-IK No. 2**. Its formal international designations include the COSPAR ID **1970-084A** and the Satellite Catalog Number **04580**. The entity is recorded in the Wolfram Language as `Entity["Satellite", "04580"]` and has a Google Knowledge Graph ID of `/g/122vxgbs`.

## References

1. Jonathan's Space Report
2. [Source](https://space.skyrocket.de/doc_sdat/interkosmos-1.htm)
3. [Source](https://www.n2yo.com/satellite/?s=04580)