# Mariner 4

> robotic spacecraft sent by NASA to Mars

**Wikidata**: [Q203805](https://www.wikidata.org/wiki/Q203805)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Mariner_4)  
**Source**: https://4ort.xyz/entity/mariner-4

Here’s the structured knowledge entry for **Mariner 4**:

---

## Summary  
Mariner 4 was a robotic spacecraft sent by NASA to Mars, becoming the first successful flyby probe to return close-up images of the Martian surface. Launched in 1964, it provided groundbreaking data about Mars' atmosphere and terrain, revolutionizing planetary science. The mission marked a major milestone in early space exploration.

## Key Facts  
- **Launch Date:** November 28, 1964  
- **Launch Vehicle:** Atlas-Agena D  
- **Operator:** Jet Propulsion Laboratory (JPL)  
- **Mass:** 260.8 kg  
- **Power Consumption:** 170 watts  
- **Mission Duration:** 1,118 days  
- **Flyby Date:** July 15, 1965 (closest approach: 9,846 km from Mars)  
- **Significant Achievement:** First spacecraft to return close-up images of Mars  
- **Orbit:** Heliocentric (artificial satellite of the Sun)  
- **Preceded/Succeeded By:** Mariner 3 (predecessor), Mariner 5 (successor)  

## FAQs  
### Q: What was Mariner 4's primary mission?  
A: Mariner 4's primary mission was to conduct a flyby of Mars, capturing the first close-up images of its surface and studying its atmosphere and environment.  

### Q: How long did Mariner 4 operate?  
A: Mariner 4 operated for 1,118 days, from its launch in 1964 until the loss of signal on December 21, 1967.  

### Q: What did Mariner 4 discover about Mars?  
A: Mariner 4 revealed Mars as a cratered, desert-like world with a thin atmosphere, dispelling earlier notions of potential habitability or canals.  

## Why It Matters  
Mariner 4 was a pivotal mission in space exploration, providing humanity's first close-up look at Mars. Its images and data transformed scientific understanding of the planet, showing a barren landscape contrary to popular speculation about Martian civilizations. The mission demonstrated NASA's capability to conduct interplanetary flybys, paving the way for future Mars missions. Mariner 4's success also validated key technologies for deep-space communication and navigation, influencing subsequent spacecraft design.  

## Notable For  
- **First successful Mars flyby:** Returned 21 images of the Martian surface.  
- **Revolutionized planetary science:** Disproved theories of Martian canals or abundant water.  
- **Long operational lifespan:** Transmitted data for over three years.  
- **Pioneered deep-space imaging:** Used a television camera system for planetary photography.  

## Body  
### Mission Overview  
- Launched on November 28, 1964, from Cape Canaveral Launch Complex 12.  
- Part of NASA's Mariner program, aimed at exploring Venus and Mars.  

### Technical Specifications  
- **Mass:** 260.8 kg  
- **Power:** 170 watts (solar panels)  
- **Orbit:** Heliocentric with semi-major axis of 199,591,220 km.  

### Key Events  
- **Flyby of Mars:** July 15, 1965, at a distance of 9,846 km.  
- **Image Transmission:** Took 21 images over 10 days.  
- **Loss of Signal:** December 21, 1967, ending the mission.  

### Scientific Contributions  
- Confirmed Mars' thin atmosphere (≈5–10 mbar surface pressure).  
- Revealed lunar-like cratered terrain.  

## Schema Markup  
```json
{
  "@context": "https://schema.org",
  "@type": "Thing",
  "name": "Mariner 4",
  "description": "Robotic spacecraft sent by NASA to Mars, first successful flyby probe to return close-up images of the Martian surface.",
  "url": "https://www.jpl.nasa.gov/missions/mariner-4/",
  "sameAs": [
    "https://www.wikidata.org/wiki/Q208727",
    "https://en.wikipedia.org/wiki/Mariner_4"
  ],
  "additionalType": "flyby probe"
}

## References

1. Jonathan's Space Report
2. Freebase Data Dumps. 2013