# H8

> upper rocket stage built by Aérospatiale

**Wikidata**: [Q126022309](https://www.wikidata.org/wiki/Q126022309)  
**Source**: https://4ort.xyz/entity/h8

## Summary
The H8 is an upper rocket stage built by Aérospatiale, primarily used as part of the Ariane 1 launch vehicle. It functioned as a space tug, delivering payloads like the SPOT 1 and Viking satellites to their target orbits. The stage was powered by a single HM7A engine and had a maiden flight in 1979.

## Key Facts
- **Manufacturer**: Aérospatiale  
- **First Flight**: December 24, 1979  
- **Last Flight**: February 22, 1986  
- **Mass**: 9,687 kg (gross), 1,457 kg (dry)  
- **Height**: 10.23 meters  
- **Diameter**: 2.66 meters  
- **Engine**: HM7A (1x) with 61.67 kN thrust  
- **Specific Impulse (Vacuum)**: 443 seconds  
- **Used By**: Ariane 1 rocket  
- **Country of Origin**: France  

## FAQs
### Q: What was the purpose of the H8 stage?  
A: The H8 was designed as a space tug to transport payloads from a reference orbit to their target orbit or interplanetary trajectory, such as deploying the SPOT 1 and Viking satellites.  

### Q: How long was the H8 in service?  
A: The H8 was operational from its maiden flight on December 24, 1979, until its last flight on February 22, 1986.  

### Q: What engine powered the H8?  
A: The H8 was powered by a single HM7A engine, producing 61.67 kN of thrust in a vacuum.  

## Why It Matters
The H8 played a critical role in Europe's early space launch capabilities as part of the Ariane 1 program. It enabled the deployment of significant payloads like the SPOT 1 Earth observation satellite and the Viking scientific satellite, contributing to advancements in remote sensing and space research. As a space tug, it demonstrated the feasibility of precision orbital maneuvers, a capability essential for modern satellite deployment and interplanetary missions. Its development by Aérospatiale also marked a milestone in European aerospace collaboration.  

## Notable For
- **First Flight**: One of the earliest European upper stages to successfully deploy payloads.  
- **Space Tug Capability**: Designed to precisely maneuver satellites into target orbits.  
- **HM7A Engine**: Featured a high-efficiency cryogenic engine with a vacuum-specific impulse of 443 seconds.  
- **Ariane 1 Legacy**: Integral to the success of the Ariane 1 launch vehicle, Europe's first independent orbital rocket.  

## Body
### Technical Specifications  
- **Mass**:  
  - Gross: 9,687 kg  
  - Dry: 1,457 kg  
- **Dimensions**:  
  - Height: 10.23 meters  
  - Diameter: 2.66 meters  
- **Propulsion**:  
  - Engine: HM7A (1x)  
  - Thrust: 61.67 kN  
  - Specific Impulse (Vacuum): 443 seconds  

### Operational History  
- **Maiden Flight**: December 24, 1979  
- **Final Flight**: February 22, 1986  
- **Payloads Deployed**: SPOT 1, Viking satellites  

### Classification  
- **Instance of**: Rocket model  
- **Subclass of**: Space tug  
- **Manufacturer**: Aérospatiale  
- **Country of Origin**: France

## References

1. [Source](http://www.astronautix.com/a/ariane1-3h8.html)
2. [Source](https://space.skyrocket.de/doc_lau/ariane.htm)
3. [Source](https://space.skyrocket.de/doc_lau_det/ariane-1.htm)