# MIDAS 4

> American early-warning satellite

**Wikidata**: [Q11764912](https://www.wikidata.org/wiki/Q11764912)  
**Source**: https://4ort.xyz/entity/midas-4

## Summary
MIDAS 4 was an American early-warning satellite launched on October 21, 1961, as part of the Missile Defense Alarm System (MIDAS). It was a reconnaissance satellite designed to detect and track ballistic missile launches, operating in a low Earth orbit before reentering the atmosphere on August 3, 1962.

## Key Facts
- **Launch Date**: October 21, 1961, at 13:53:03 UTC from Vandenberg Space Launch Complex 3 East.
- **Mass**: 1,800 kilograms.
- **Dimensions**: 6 meters in length and 1.5 meters in diameter.
- **Launch Vehicle**: Atlas-Agena B (serial number 105D/1202).
- **Operator/Funder**: United States Air Force.
- **Manufacturer**: Lockheed Corporation (general contractor).
- **Power Source**: Bell Model 8081 propulsion system and two spacecraft solar arrays.
- **Orbital Decay**: Reentered Earth's atmosphere on August 3, 1962.
- **Classification**: Reconnaissance satellite for intelligence and military applications.
- **Part of**: Missile Defense Alarm System (MIDAS) and Project West Ford (as dispenser), SECOR (as transponder).

## FAQs
### Q: What was the purpose of MIDAS 4?
A: MIDAS 4 was an early-warning satellite designed to detect and track ballistic missile launches, providing critical data for the U.S. military's defense systems.

### Q: How long did MIDAS 4 remain in orbit?
A: MIDAS 4 operated in orbit until August 3, 1962, when it reentered Earth's atmosphere.

### Q: Who launched MIDAS 4?
A: MIDAS 4 was launched by the United States Air Force using an Atlas-Agena B rocket from Vandenberg Air Force Base.

### Q: What was the significance of MIDAS 4 in the MIDAS program?
A: MIDAS 4 was part of a series of satellites that preceded and succeeded it (MIDAS 3 and MIDAS 5), contributing to the early development of the Missile Defense Alarm System.

### Q: What were the key technical specifications of MIDAS 4?
A: MIDAS 4 had a mass of 1,800 kg, a length of 6 meters, and a diameter of 1.5 meters, and was powered by a Bell Model 8081 propulsion system and solar arrays.

## Why It Matters
MIDAS 4 played a crucial role in the early development of the U.S. military's ballistic missile early-warning system. As part of the Missile Defense Alarm System (MIDAS), it provided real-time data on missile launches, enhancing the nation's defense capabilities. The satellite's successful operation demonstrated the feasibility of using space-based systems for strategic surveillance. MIDAS 4's reentry in 1962 marked the end of its operational life but contributed to the evolution of space-based reconnaissance and early-warning technologies. Its legacy influenced subsequent satellite programs, including those focused on missile defense and space surveillance.

## Notable For
- **First in Series**: MIDAS 4 was the fourth satellite in the MIDAS program, following MIDAS 3 and preceding MIDAS 5.
- **Reconnaissance Capability**: It was classified as a reconnaissance satellite, collecting data for intelligence and military applications.
- **Low Earth Orbit**: Operated in a low Earth orbit, providing timely detection of ballistic missile launches.
- **Technical Innovation**: Featured advanced propulsion and power systems, including solar arrays, for sustained operation.
- **Part of Larger Program**: Integrated with Project West Ford (as dispenser) and SECOR (as transponder), showcasing multi-system collaboration.

## Body
### Overview
MIDAS 4 was an American early-warning satellite launched on October 21, 1961, as part of the Missile Defense Alarm System (MIDAS). It was designed to detect and track ballistic missile launches, operating in a low Earth orbit before reentering the atmosphere on August 3, 1962.

### Technical Specifications
- **Mass**: 1,800 kilograms.
- **Dimensions**: 6 meters in length and 1.5 meters in diameter.
- **Power Source**: Bell Model 8081 propulsion system and two spacecraft solar arrays.
- **Launch Vehicle**: Atlas-Agena B (serial number 105D/1202).

### Operational Details
- **Launch Date**: October 21, 1961, at 13:53:03 UTC from Vandenberg Space Launch Complex 3 East.
- **Operator/Funder**: United States Air Force.
- **Manufacturer**: Lockheed Corporation (general contractor).
- **Orbital Decay**: Reentered Earth's atmosphere on August 3, 1962.

### Classification and Role
- **Classification**: Reconnaissance satellite for intelligence and military applications.
- **Part of**: Missile Defense Alarm System (MIDAS), Project West Ford (as dispenser), and SECOR (as transponder).

### Historical Context
- **Preceded/Succeeded by**: MIDAS 3 and MIDAS 5, respectively.
- **Significance**: Contributed to the early development of space-based early-warning systems, enhancing the U.S. military's defense capabilities.

```json
{
  "@context": "https://schema.org",
  "@type": "Thing",
  "name": "MIDAS 4",
  "description": "American early-warning satellite launched in 1961 as part of the Missile Defense Alarm System.",
  "additionalType": "Spacecraft",
  "manufacturer": {
    "@type": "Organization",
    "name": "Lockheed Corporation"
  },
  "funder": {
    "@type": "Organization",
    "name": "United States Air Force"
  },
  "launchDate": "1961-10-21",
  "launchVehicle": "Atlas-Agena B",
  "mass": {
    "@type": "QuantitativeValue",
    "value": "1800",
    "unitCode": "KGM"
  },
  "length": {
    "@type": "QuantitativeValue",
    "value": "6",
    "unitCode": "MTR"
  },
  "diameter": {
    "@type": "QuantitativeValue",
    "value": "1.5",
    "unitCode": "MTR"
  },
  "orbit": "Low Earth Orbit",
  "decayDate": "1962-08-03",
  "sameAs": [
    "https://www.wikidata.org/wiki/Q123456789",
    "https://en.wikipedia.org/wiki/MIDAS_4"
  ]
}

## References

1. [Source](https://space.skyrocket.de/doc_sdat/midas-3.htm)
2. Jonathan's Space Report
3. [Source](https://nssdc.gsfc.nasa.gov/nmc/spacecraft/displayTrajectory.action?id=1961-028A)
4. [Source](https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1961-028A)