# Lincoln Experimental Satellite 1

> American communications satellite which stopped transmitting in 1967, but resumed c. 2012

**Wikidata**: [Q11756909](https://www.wikidata.org/wiki/Q11756909)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/LES-1)  
**Source**: https://4ort.xyz/entity/lincoln-experimental-satellite-1

Here’s the structured knowledge entry for **Lincoln Experimental Satellite 1**:

---

## Summary  
Lincoln Experimental Satellite 1 (LES-1) was an American experimental communications satellite launched in 1965 to test new technologies. It stopped transmitting in 1967 but unexpectedly resumed signals around 2012, making it a notable case of a "zombie satellite." It was part of a series developed by MIT Lincoln Laboratory for the U.S. Air Force.

## Key Facts  
- **Launch Date:** February 11, 1965, from Cape Canaveral Space Launch Complex 20.  
- **Launch Vehicle:** Titan IIIA (serial number 3A-3).  
- **Mass:** 31 kg (launch weight).  
- **Diameter:** 61 cm.  
- **Power Source:** Solar cells generating 26 watts.  
- **Operators:** U.S. Air Force and MIT Lincoln Laboratory.  
- **COSPAR ID:** 1965-008C.  
- **Significant Events:** Stopped transmitting in 1967, resumed signals circa December 18, 2012.  
- **Followed By:** Lincoln Experimental Satellite 2 (LES-2).  

## FAQs  
### Q: Why did LES-1 stop transmitting in 1967?  
A: The exact cause is unclear, but it likely exhausted its power or experienced technical failure, common for early experimental satellites.  

### Q: How was LES-1 rediscovered in 2012?  
A: Amateur radio enthusiasts detected its signal, revealing it had spontaneously resumed transmissions after decades of silence.  

### Q: What was the purpose of LES-1?  
A: It tested advanced communications technologies, including transponder and frequency stability systems, paving the way for later satellites.  

## Why It Matters  
LES-1 was pivotal in demonstrating the feasibility of experimental satellite communications technology during the Cold War era. Its unexpected reactivation in 2012 provided unique insights into the longevity and behavior of defunct satellites, sparking interest in space debris and satellite lifespan. As part of the Lincoln Experimental Satellite series, it contributed to advancements in military and civilian telecommunications, influencing later designs. The satellite’s revival also highlighted the potential for unintended signal interference from dormant space objects.  

## Notable For  
- **Unexpected Reactivation:** One of the few satellites to resume transmissions after decades of inactivity.  
- **Early Pioneer:** Among the first to test critical communications technologies later adopted widely.  
- **Lightweight Design:** At 31 kg, it was relatively small for its era.  
- **Longevity:** Survived in orbit far beyond its operational lifespan.  

## Body  
### Launch and Mission  
- Launched on February 11, 1965, aboard a Titan IIIA rocket.  
- Primary mission: Demonstrate experimental transponder and frequency stability technologies.  

### Design and Specifications  
- **Shape:** Cylindrical, 61 cm in diameter.  
- **Power:** 2,376 solar cells generating 26 watts.  
- **Manufacturer:** MIT Lincoln Laboratory.  

### Operational History  
- Ceased transmissions in 1967 due to presumed power failure.  
- Rediscovered transmitting signals circa December 18, 2012, by amateur astronomers.  

### Legacy  
- Part of the Lincoln Experimental Satellite series, paving the way for later military and civilian comms satellites.  
- Unplanned reactivation raised questions about space debris management.  

## Schema Markup  
```json
{
  "@context": "https://schema.org",
  "@type": "Thing",
  "name": "Lincoln Experimental Satellite 1",
  "description": "American experimental communications satellite launched in 1965, which resumed transmissions unexpectedly in 2012.",
  "sameAs": [
    "https://www.wikidata.org/wiki/Q122961732",
    "https://en.wikipedia.org/wiki/LES-1"
  ],
  "additionalType": ["Communications Satellite", "Technology Demonstration Spacecraft"]
}

## References

1. [Source](https://space.skyrocket.de/doc_sdat/les-1.htm)
2. Jonathan's Space Report
3. [Source](https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1965-008C)
4. Beyond the Ionosphere: Fifty Years of Satellite Communication
5. [Source](https://www.dd1us.de/spacesounds%204b.html)