# Proton

> family of Soviet/Russian launch vehicles

**Wikidata**: [Q249231](https://www.wikidata.org/wiki/Q249231)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Proton_(rocket_family))  
**Source**: https://4ort.xyz/entity/proton

## Summary
Proton is a family of expendable Soviet/Russian heavy-lift launch vehicles that has carried both crewed lunar-flyby spacecraft and most Russian planetary probes since the 1960s. Built by the Khrunichev Center, the rocket family traces its design to the UR-500 ICBM and is scheduled to be phased out by the newer Angara family.

## Key Facts
- Classified as an expendable launch-vehicle family; subclass of heavy-lift rockets
- Country of origin: Soviet Union (first launch era), continuing in Russia today
- Manufacturer: Khrunichev State Research and Production Space Center
- Based on the UR-500 ballistic missile; native Russian name "Протон"
- Replaced by the Angara rocket family (no specific retirement date given)
- 51 Wikipedia-language editions contain an article on the vehicle
- Not to be confused with the particle "proton"; Wikidata disambiguation page exists
- Encyclopædia Britannica online ID: topic/Proton-Russian-launch-vehicle
- Listed as a Level-4 vital article in English Wikipedia (as of 31 Oct 2022)

## FAQs
### Q: What rockets belong to the Proton family?
A: The line includes the original UR-500, the Proton-K (Soviet/Russian carrier rocket) and the later Proton-M heavy-lift version. All variants are expendable.

### Q: Is Proton still flying?
A: The source material does not give a final flight date, but it states that the Angara family is the designated replacement; therefore Proton is being phased out.

### Q: Did Proton carry cosmonauts?
A: The Soyuz 7K-L1 circumlunar-flyby spacecraft was among its payloads, but no human-rated Proton version is mentioned in the source.

### Q: What scientific missions launched on Proton?
A: Notable payloads include Luna 15, Lunokhod 1, Venera-D (proposed), and the Proton 1-3 scientific satellites.

## Why It Matters
Proton served as the Soviet Union's—and later Russia's—primary heavy-lift bridge to space for more than half a century. Its high lift capacity enabled the launch of sample-return probes, lunar rovers, and geostationary satellites that shaped early planetary science and global communications. Because it was derived from an ICBM, Proton also illustrates the Cold-War conversion of military technology to civilian space use. The rocket's long service record (counted in hundreds of flights) made it a workhorse for International Launch Services commercial missions, delivering Western, Russian, and Asian telecom spacecraft to geostationary orbit. With Angara now supplanting it, Proton's legacy lies in proving that a single, highly optimized design could evolve through incremental upgrades to meet ever-larger payload demands without building an entirely new vehicle.

## Notable For
- First Soviet super-heavy launcher derived from an ICBM (UR-500)
- Carried Luna 15 (1969) and Lunokhod 1, the first successful lunar rover
- Proton-M variant remains one of Russia's most powerful operational rockets
- More than 50 language editions of Wikipedia document the rocket, indicating global cultural impact
- Officially earmarked for replacement by the environmentally friendlier Angara family

## Body
### Design Origins
Proton began as the UR-500 intercontinental ballistic missile. Khrunichev State Research and Production Space Center adapted the missile into a space-launch configuration, retaining its hypergolic first-stage propulsion.

### Variants
- Proton-K: three-stage carrier rocket that flew Soviet planetary and early commercial payloads
- Proton-M: modernized, higher-thrust version optimized for heavy geostationary satellites

### Operational Use
The family lofted scientific craft such as Luna 15, Lunokhod 1, Proton 1-3, and the proposed Venera-D Venus probe. Commercial flights carried Inmarsat-5 F2, Intelsat 10-02, SES-7, and many GLONASS navigation satellites (Kosmos 2447, 2448, 2456, 2458, 2461).

### Retirement Path
No final launch date appears in the source, but the Angara family is explicitly identified as the successor system.

## Schema Markup
```json
{
  "@context": "https://schema.org",
  "@type": "Thing",
  "name": "Proton",
  "description": "Family of Soviet/Russian expendable heavy-lift launch vehicles derived from the UR-500 missile.",
  "sameAs": [
    "https://www.wikidata.org/wiki/Q720374",
    "https://en.wikipedia.org/wiki/Proton_(rocket_family)"
  ],
  "additionalType": "Rocket Family"
}

## References

1. Freebase Data Dumps. 2013
2. [Source](http://larousse.fr/encyclopedie/divers/Proton/139695)
3. Encyclopædia Britannica Online