# AMSAT Echo

> American amateur radio satellite

**Wikidata**: [Q4653126](https://www.wikidata.org/wiki/Q4653126)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/AMSAT-OSCAR_51)  
**Source**: https://4ort.xyz/entity/amsat-echo

## Summary
AMSAT Echo (AMSAT-OSCAR 51, AO-51) is an American amateur radio satellite launched into low Earth orbit on 29 June 2004. It was a ~10 kilogram spacecraft built by AAC SpaceQuest and operated by the Radio Amateur Satellite Corporation (AMSAT) of North America until a loss of signal in November 2011.

## Key Facts
- AMSAT Echo is an American amateur radio satellite, also known as AMSAT-OSCAR 51, AMSAT AO-51, AO-51, and AMSAT E.
- Launch date: 2004-06-29 at 06:30:06 (UTC) from Baikonur Cosmodrome Site 109.
- Launch vehicle: Dnepr (launch vehicle identifier/serial listed as 450-3341-631).
- Manufacturer: AAC SpaceQuest.
- Operator: Radio Amateur Satellite Corporation — North America (AMSAT).
- Mass: 10 kilograms.
- Orbit: low Earth orbit (satellite_of: low Earth orbit).
- COSPAR ID / NSSDCA ID: 2004-025K; SCN: 28375.
- Country of origin: United States.
- Significant events: rocket launch at Baikonur Cosmodrome Site 109 on 2004-06-29; loss of signal in November 2011.
- Replaced by: Fox-1A.

## FAQs
### Q: What is AMSAT Echo?
A: AMSAT Echo (also AMSAT-OSCAR 51 or AO-51) is an American amateur radio satellite launched into low Earth orbit in June 2004 and operated by AMSAT North America.

### Q: When and where was AMSAT Echo launched?
A: AMSAT Echo was launched on 2004-06-29 at 06:30:06 from Baikonur Cosmodrome Site 109 on a Dnepr launch vehicle.

### Q: Who built and operated AMSAT Echo?
A: The satellite was manufactured by AAC SpaceQuest and operated by the Radio Amateur Satellite Corporation — North America (AMSAT).

### Q: What happened to AMSAT Echo?
A: AMSAT Echo experienced a loss of signal in November 2011 and was later followed in AMSAT’s small-satellite lineup by the Fox-1A satellite.

## Why It Matters
AMSAT Echo is part of the OSCAR (Orbital Satellite Carrying Amateur Radio) lineage and represents a compact, dedicated amateur radio platform flown by a community-based operator. As a 10 kg spacecraft manufactured by AAC SpaceQuest and managed by AMSAT North America, it demonstrates the small-satellite approach used by amateur radio organizations to place functional radio payloads into low Earth orbit. Its launch on a converted Dnepr vehicle from Baikonur in 2004 underscores international launch partnerships used for specialist payloads. The satellite’s operational lifetime, ending with a loss of signal in November 2011, and its formal succession by Fox-1A illustrate the continuity of amateur radio satellite programs and the iterative development of successor satellites. For radio amateurs, educators, and small-satellite engineers, AMSAT Echo is a verifiable example of community-driven spacecraft design, international launch use, and the operational lifecycle of an OSCAR-class amateur satellite.

## Notable For
- Bearing the OSCAR designation AMSAT-OSCAR 51 (AO-51), linking it to the long-running OSCAR series of amateur radio satellites.
- Launch on a converted ICBM Dnepr vehicle from Baikonur Cosmodrome Site 109 on 2004-06-29.
- Lightweight design with a mass of approximately 10 kilograms.
- Manufactured by AAC SpaceQuest and operated by Radio Amateur Satellite Corporation — North America (AMSAT).
- End of operational signal in November 2011 and subsequent replacement in AMSAT’s lineup by Fox-1A.

## Body

### Overview
- Name and aliases: AMSAT Echo; AMSAT-OSCAR 51; AMSAT AO-51; AO-51; AMSAT E.
- Class: amateur radio satellite (a type of satellite that transmits amateur radio).
- Country of origin: United States.
- Operator: Radio Amateur Satellite Corporation — North America (AMSAT).
- Manufacturer: AAC SpaceQuest.

### Launch and orbit
- Launch date and time: 2004-06-29 at 06:30:06 (UTC).
- Launch site: Baikonur Cosmodrome Site 109.
- Launch vehicle: Dnepr (launch identifier/serial: 450-3341-631).
- Orbit regime: low Earth orbit.

### Technical specifications
- Mass: 10 kilograms.
- Instance of: amateur radio satellite.
- Image: available at https://commons.wikimedia.org/wiki/Special:FilePath/AO-51-2.jpg.

### Operational history
- Entered orbit following launch on 2004-06-29.
- Operated by AMSAT North America during its mission life.
- Significant mission event: loss of signal recorded in November 2011.
- Replaced in AMSAT’s small-satellite program by Fox-1A.

### Identifiers and catalog data
- COSPAR ID: 2004-025K.
- NSSDCA ID: 2004-025K.
- SCN (Satellite Catalog Number): 28375.
- Freebase ID: /m/03slfg.
- Wikipedia title: AMSAT-OSCAR 51.
- Commons category: OSCAR 51.
- Sitelink count: 4.
- Available language links on Wikipedia/Commons: commons, de, en, pt.

## References

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