# SIGNE 3

> Orbital gamma-ray observatory

**Wikidata**: [Q16325278](https://www.wikidata.org/wiki/Q16325278)  
**Source**: https://4ort.xyz/entity/signe-3

## Summary
SIGNE 3 was an orbital gamma-ray observatory satellite launched by France's CNES in 1977. It was designed to study high-energy cosmic gamma rays and operated until its orbit decayed in 1979.

## Key Facts
- **Class**: Artificial satellite
- **Launch date**: June 17, 1977
- **Launch site**: Kapustin Yar, Soviet Union
- **Launch vehicle**: Kosmos-3M rocket
- **Manufacturer**: Matra (spacecraft bus) and CNES (measuring instrument)
- **Mass**: 102 kilograms
- **Orbital inclination**: 50.6 degrees
- **Apoapsis**: 524 kilometers
- **Periapsis**: 452 kilometers
- **Decay date**: June 21, 1979
- **Aliases**: D2B Gamma, СНЕГ-3

## FAQs
### Q: What was SIGNE 3's mission?
A: SIGNE 3 was an orbital gamma-ray observatory designed to study high-energy cosmic gamma rays, helping scientists understand cosmic phenomena.

### Q: Who launched SIGNE 3?
A: SIGNE 3 was launched by the French space agency CNES on June 17, 1977, using a Kosmos-3M rocket from Kapustin Yar.

### Q: How long did SIGNE 3 operate?
A: SIGNE 3 operated in orbit until its decay on June 21, 1979, a period of about two years.

### Q: What was unique about SIGNE 3's design?
A: SIGNE 3 was built with a spacecraft bus by Matra and carried a measuring instrument developed by CNES, marking a collaborative effort between French entities.

### Q: What was SIGNE 3's orbital altitude?
A: SIGNE 3 had a periapsis of 452 kilometers and an apoapsis of 524 kilometers, with an orbital inclination of 50.6 degrees.

## Why It Matters
SIGNE 3 was a significant contribution to gamma-ray astronomy, providing valuable data on cosmic gamma-ray emissions. As an early orbital observatory, it helped advance understanding of high-energy phenomena in space. Its mission supported international collaboration in space science, with CNES and Matra working together to develop and launch the satellite. Despite its relatively short operational life, SIGNE 3 laid groundwork for future gamma-ray missions, demonstrating the feasibility of studying these cosmic events from orbit.

## Notable For
- First orbital gamma-ray observatory launched by France
- Collaborative development between CNES and Matra
- Provided early data on cosmic gamma-ray emissions
- Operated in a low Earth orbit for scientific research
- Short but impactful mission in the field of high-energy astronomy

## Body
### Mission Overview
SIGNE 3 was an orbital gamma-ray observatory launched to study high-energy cosmic gamma rays. It was part of a broader effort in space-based gamma-ray astronomy, contributing to the understanding of cosmic phenomena.

### Launch Details
- **Launch Date**: June 17, 1977
- **Launch Site**: Kapustin Yar, Soviet Union
- **Launch Vehicle**: Kosmos-3M rocket
- **Manufacturer**: Matra (spacecraft bus), CNES (measuring instrument)

### Orbital Characteristics
- **Apoapsis**: 524 kilometers
- **Periapsis**: 452 kilometers
- **Orbital Inclination**: 50.6 degrees
- **Decay Date**: June 21, 1979

### Technical Specifications
- **Mass**: 102 kilograms
- **Aliases**: D2B Gamma, СНЕГ-3
- **Commons Category**: SIGNE 3

### Scientific Contributions
SIGNE 3's mission provided valuable data on gamma-ray emissions, supporting research in high-energy astronomy. Its short operational period was sufficient to yield significant scientific insights.

## References

1. Jonathan's Space Report