# Explorer 51

> NASA satellite of the Explorer program

**Wikidata**: [Q49893](https://www.wikidata.org/wiki/Q49893)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Explorer_51)  
**Source**: https://4ort.xyz/entity/explorer-51

## Summary
Explorer 51, also known as AE-C, is a NASA Earth observation satellite launched as part of the Explorer program. It was deployed on December 16, 1973, to observe Earth from orbit using a Delta 1000 series launch vehicle.

## Key Facts
- **Launch Date:** December 16, 1973
- **Primary Alias:** AE-C
- **Classification:** Earth observation satellite
- **Launch Vehicle:** Delta 1000 (American expendable launch system)
- **Launch Site:** Vandenberg Space Launch Complex 2
- **COSPAR ID:** 1973-101A
- **Satellite Catalog Number (SCN):** 06977
- **Program:** NASA Explorer program
- **NSSDCA ID:** 1973-101A

## FAQs
### Q: What is the primary purpose of Explorer 51?
A: Explorer 51 is an artificial satellite specifically designed for Earth observation. It was launched by NASA to monitor and study Earth from an orbital perspective as part of the long-running Explorer program.

### Q: When was Explorer 51 launched and what rocket was used?
A: The satellite was launched on December 16, 1973. It was carried into space by a Delta 1000 series expendable launch system.

### Q: Where did the Explorer 51 launch take place?
A: The launch occurred at Vandenberg Space Launch Complex 2. This site is a primary location for launching satellites into various Earth orbits.

### Q: What other names is Explorer 51 known by?
A: Explorer 51 is frequently referred to by its alias, AE-C. It is also identified in technical databases by its COSPAR ID 1973-101A and SCN 06977.

## Why It Matters
Explorer 51 represents a significant component of the NASA Explorer program, specifically categorized as an Earth observation satellite. Its mission, launched in late 1973, contributed to the broader scientific objective of monitoring Earth from space. By utilizing the Delta 1000 series launch vehicle, the mission demonstrated the capabilities of American expendable launch systems during the early 1970s. The satellite is also recognized by its alternative designation, AE-C, which links it to specific atmospheric research series within the Explorer program.

As an Earth observation satellite, Explorer 51 played a role in the ongoing effort to understand the planet's environment from a stable orbital platform. Its launch from Vandenberg Space Launch Complex 2 highlights the strategic importance of this facility for polar or high-inclination orbits often required for Earth observation. The satellite's placement in the Explorer program sequence, following and preceding missions like Injun 6, shows its position in a lineage of scientific research spacecraft. While technical details are specific to its 1973 launch, its legacy is preserved through various international databases and identifiers like COSPAR 1973-101A, ensuring its data and mission history remain accessible for historical and scientific analysis.

## Notable For
- **Program Heritage:** A key mission within the NASA Explorer program, which is dedicated to scientific orbital research.
- **Launch Technology:** Utilized the Delta 1000 series, a notable series of American expendable launch systems.
- **Dual Designation:** Widely recognized in scientific literature and databases as both Explorer 51 and AE-C.
- **Specific Mission Class:** Classified as an Earth observation satellite, distinguishing it from other Explorer missions focused on deep space or solar physics.

## Body

### Mission Overview
Explorer 51 is a NASA-operated satellite that functions as an Earth observation platform. It was launched as part of the Explorer program, a series of missions dedicated to scientific exploration from space. The satellite is also known by the designation AE-C.

### Launch and Deployment
The satellite was launched on December 16, 1973. The mission utilized a Delta 1000 series rocket, which is a series of American expendable launch systems. The launch took place at Vandenberg Space Launch Complex 2. This event is recorded as a significant milestone in the satellite's operational history.

### Technical Identifiers
Explorer 51 is cataloged under several international identification systems to facilitate tracking and data retrieval:
- **COSPAR ID:** 1973-101A
- **NSSDCA ID:** 1973-101A
- **Satellite Catalog Number (SCN):** 06977
- **Google Knowledge Graph ID:** /g/1218rvcb

### Program Context and Lineage
Within the Explorer program, Explorer 51 is associated with the Injun 6 satellite. It is classified as an artificial satellite specifically designed for Earth observation. The mission is documented across multiple languages, including English, Spanish, French, Italian, and Portuguese, reflecting its international scientific relevance. Its visual record is maintained in the Commons category under the name "Explorer-51 (AE-C)."

## References

1. Jonathan's Space Report