# Beacon Explorer-A

> NASA research satellite of the Explorer program, lost due to a launch failure

**Wikidata**: [Q5723959](https://www.wikidata.org/wiki/Q5723959)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Explorer_S-66)  
**Source**: https://4ort.xyz/entity/beacon-explorer-a

## Summary
Beacon Explorer-A (also known as Explorer S-66, S-66A, BE-A) was a United States NASA research satellite in the Explorer program that was lost in a launch failure on 1964-03-19. The spacecraft, built by the Johns Hopkins University Applied Physics Laboratory and weighing 59 kg, failed to reach orbit after a Delta B launch from Cape Canaveral SLC-17A.

## Key Facts
- Beacon Explorer-A is a NASA research satellite and part of the Explorers Program.  
- Launch date and time: 1964-03-19 at 11:13:41 (launch attempt from Cape Canaveral Space Launch Complex 17A).  
- Launch vehicle: Delta B (vehicle serial/identifier 391/D-024).  
- Mission outcome: lost due to a launch failure on 1964-03-19.  
- Manufacturer: Johns Hopkins University Applied Physics Laboratory.  
- Mass at launch: 59 kilograms.  
- Spacecraft bus diameter: 0.4668 metre.  
- Spacecraft solar array span: 7.2563 metre; powered by 4 spacecraft solar arrays.  
- Operator: National Aeronautics and Space Administration (NASA).  
- NSSDCA ID: EXS-66A; common aliases: S-66A, BE-A, Explorer S-66.  
- Followed by (next related mission): Beacon Explorer-B.

## FAQs
### Q: What happened to Beacon Explorer-A?
A: Beacon Explorer-A was lost in a launch failure during its launch attempt on 1964-03-19 from Cape Canaveral Space Launch Complex 17A and did not reach orbit.

### Q: Who built Beacon Explorer-A and who operated it?
A: The satellite was manufactured by the Johns Hopkins University Applied Physics Laboratory and operated by the National Aeronautics and Space Administration (NASA).

### Q: What were the spacecraft's size and mass?
A: The spacecraft had a bus diameter of 0.4668 metre, a solar array span of 7.2563 metre, and a launch mass of 59 kilograms.

### Q: What launch vehicle was used for Beacon Explorer-A?
A: The mission used a Delta B launch vehicle, identified as serial 391/D-024.

## Why It Matters
Beacon Explorer-A is part of the historical record of the U.S. Explorer series and exemplifies the technical and operational risks inherent in early satellite programs. Although the mission failed to reach orbit, the spacecraft’s design, build provenance (Johns Hopkins University Applied Physics Laboratory), and integration into the Explorer program reflect mid-1960s efforts to deploy compact research satellites powered by multiple solar arrays. Failures such as this informed later engineering, launch-procedure, and mission-planning improvements across the program. The mission also forms a documented link in a sequence of related missions (it was followed by Beacon Explorer-B), contributing to continuity in program objectives and hardware evolution even when individual launches were unsuccessful. As an entry in NASA and NSSDCA catalogs (NSSDCA ID EXS-66A), Beacon Explorer-A remains a referent for historical launch records, vehicle serial tracking (Delta B 391/D-024), and manufacturing work by APL.

## Notable For
- Loss during launch: the mission was lost due to a launch failure on 1964-03-19.  
- Small research satellite design: mass of 59 kg with a compact bus (0.4668 m).  
- Solar-powered: used four spacecraft solar arrays with a combined span listed as 7.2563 m.  
- Built by a major research lab: manufactured by Johns Hopkins University Applied Physics Laboratory.  
- Part of the Explorer program lineage and cataloged as EXS-66A.

## Body

### Overview
- Official common names: Beacon Explorer-A, Explorer S-66, S-66A, BE-A.  
- Instance: research satellite (listed as a former entity due to mission loss).  
- Program: part of NASA's Explorers Program.  
- Country of origin/operator: United States / National Aeronautics and Space Administration.

### Technical specifications
- Mass: 59 kg.  
- Spacecraft bus diameter: 0.4668 metre.  
- Spacecraft solar array span: 7.2563 metre (qualifier: spacecraft solar array).  
- Power: supplied by spacecraft solar arrays; quantity listed as 4 solar arrays.  
- Manufacturer: Johns Hopkins University Applied Physics Laboratory.  
- Identifiers: NSSDCA ID EXS-66A; Google Knowledge Graph ID /g/120mnl_5.  
- Image reference: available at https://commons.wikimedia.org/wiki/Special:FilePath/Explorer-27.jpg.

### Launch and mission outcome
- Launch date and time (attempt): 1964-03-19 at 11:13:41.  
- Launch site: Cape Canaveral Space Launch Complex 17A.  
- Launch vehicle: Delta B, vehicle identifier 391/D-024.  
- Significant events logged: rocket launch from Cape Canaveral SLC-17A on 1964-03-19; launch failure on 1964-03-19.  
- Mission outcome: failed to reach orbit and was lost due to the launch failure.

### Operations and program context
- Operated by NASA as part of efforts to place research satellites into orbit under the Explorers Program.  
- Followed in sequence by Beacon Explorer-B.  
- Categorized as a research satellite and recorded in program catalogs and archives despite mission failure.

### Related missions and continuity
- Immediate successor: Beacon Explorer-B (also a NASA research/ionospheric satellite in the program sequence).  
- The mission appears in launch records alongside Delta B vehicle serial 391/D-024 and is referenced in NASA and launch documentation.

## References

1. [Source](https://space.skyrocket.de/doc_sdat/explorer_be.htm)
2. Jonathan's Space Report
3. [Source](https://ntrs.nasa.gov/citations/19650005987)