# CAT-4

> ESA artificial satellite

**Wikidata**: [Q48561](https://www.wikidata.org/wiki/Q48561)  
**Source**: https://4ort.xyz/entity/cat-4

## Summary
CAT-4 is a European Space Agency research satellite launched on December 20, 1981, aboard an Ariane 1 rocket. It was part of the CAT (Capsule Ariane Technologique) series and is currently classified as a derelict satellite in orbit.

## Key Facts
- CAT-4 has SCN number 13011 and COSPAR ID 1981-122B
- It was launched on December 20, 1981, at 01:29:00 from ELA-1
- The satellite was powered by primary cell technology
- It follows CAT-3 in the CAT series of satellites
- CAT-4 was manufactured by both Aeritalia and Selenia
- The launch vehicle used was an Ariane 1 (specifically L04)
- The satellite has aliases including Ariane Technological Capsule 4, Technological Capsule 4, CAT-04, Thesee, and Capsule Ariane Technologique 4
- It has a sitelink count of 2 and is available in Wikipedia languages: Galician and Portuguese

## FAQs
### Q: What was the purpose of CAT-4?
A: CAT-4 was a research satellite operated by the European Space Agency, designed for technological experimentation and validation in space conditions.

### Q: When and how was CAT-4 launched?
A: CAT-4 was launched on December 20, 1981, at 01:29:00 from ELA-1 using an Ariane 1 rocket (specifically L04).

### Q: What is the current status of CAT-4?
A: CAT-4 is currently classified as a derelict satellite, meaning it has been decommissioned or become nonfunctional but remains in orbit.

### Q: Who manufactured CAT-4?
A: CAT-4 was manufactured by both Aeritalia and Selenia companies.

### Q: What power source did CAT-4 use?
A: The satellite was powered by primary cell technology.

## Why It Matters
CAT-4 represents an important technological achievement in European space research capabilities during the early 1980s. As part of the CAT (Capsule Ariane Technologique) series, it contributed to validating technologies for future ESA missions and helped establish Europe's independent access to space through the Ariane program. The satellite's research objectives included testing systems and components that would be used in more complex missions, serving as a stepping stone in ESA's technological development. As a derelict satellite now in space, it also represents one of the many human-made objects orbiting Earth, contributing to the growing issue of space debris management.

## Notable For
- Being the fourth satellite in the CAT series following CAT-3
- Being launched aboard the fourth Ariane 1 rocket (L04) in December 1981
- Having the COSPAR ID 1981-122B
- Being classified as both a research satellite and a derelict satellite
- Having multiple technical names including Ariane Technological Capsule 4 and Thesee

## Body
### Overview
CAT-4 (also known as Ariane Technological Capsule 4, Technological Capsule 4, CAT-04, Thesee, and Capsule Ariane Technologique 4) is a research satellite operated by the European Space Agency. It was launched as part of the CAT series of technological capsules designed for space experimentation.

### Launch Details
- Launch date: December 20, 1981
- Launch time: 01:29:00
- Launch site: ELA-1 (Étage d'Ariane 1)
- Launch vehicle: Ariane 1 (L04)

### Technical Specifications
- SCN: 13011
- COSPAR ID: 1981-122B
- Power source: Primary cell
- Classification: Research satellite, derelict satellite
- Manufacturer: Aeritalia and Selenia

### Program Context
- Operator: European Space Agency
- Predecessor: CAT-3
- Series: CAT (Capsule Ariane Technologique)
- Wikipedia languages available: Galician (gl), Portuguese (pt)

## Schema Markup
```json
{
  "@context": "https://schema.org",
  "@type": "Thing",
  "name": "CAT-4",
  "description": "European Space Agency research satellite launched on December 20, 1981",
  "url": "",
  "sameAs": [
    "https://www.wikidata.org/wiki/Q13011"
  ],
  "additionalType": "research satellite, derelict satellite"
}

## References

1. [Source](https://space.skyrocket.de/doc_sdat/cat-1.htm)
2. Jonathan's Space Report