# Sputnik 1

> first artificial Earth satellite

**Wikidata**: [Q80811](https://www.wikidata.org/wiki/Q80811)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Sputnik_1)  
**Source**: https://4ort.xyz/entity/sputnik-1

## Summary
Sputnik 1 was the first artificial Earth satellite, launched by the Soviet Union on 4 October 1957 from Gagarin's Start. This 83.6-kg aluminium sphere, 58 cm in diameter, transmitted radio signals for 21 days and completed 1,440 orbits before re-entering the atmosphere on 4 January 1958, marking the start of the space age and the US–USSR space race.

## Key Facts
- Launch date: 4 October 1957 at 19:28:34 UTC
- Launch vehicle: Sputnik (M1-PS configuration) rocket
- Operator: Soviet Union; built by S.P. Korolev Rocket and Space Corporation Energia
- Mass: 83.6 kg at launch
- Dimensions: 58 cm diameter
- Orbit: 215 km × 940 km, 96.2-minute period, 65.1° inclination
- Signal: 1-watt radio transmitter broadcasting on 20.005 MHz and 40.002 MHz
- Mission duration: 92 days; last signal 26 October 1957; re-entry 4 January 1958
- COSPAR ID: 1957-001B; Harvard designation: 1957 Alpha 2
- Followed by: Sputnik 2 (carried dog Laika) in November 1957

## FAQs
### Q: What did Sputnik 1 actually do?
A: It emitted continuous radio beeps that were picked up by amateur and military stations worldwide, proving that a man-made object could survive and be tracked in orbit.

### Q: How long did Sputnik 1 stay in space?
A: The satellite remained in orbit for 92 days, completing 1,440 laps around Earth before atmospheric drag caused it to burn up on 4 January 1958.

### Q: Why was Sputnik 1 so significant?
A: Its launch demonstrated Soviet rocket capability to deliver payloads anywhere on Earth, spurred massive US investment in science education and NASA, and officially opened the space race.

### Q: Could you see Sputnik 1 from the ground?
A: The sphere itself was too small, but its attached second-stage rocket casing, much larger and polished, was visible to the naked eye as a bright moving “star” at dawn or dusk.

## Why It Matters
Sputnik 1’s beeping signal was a geopolical thunderclap: it proved that inter-continental ballistic missiles were feasible and that space could be militarised. The event triggered the creation of DARPA, NASA, and the US National Defense Education Act, pouring billions into science and engineering curricula. For the USSR, it delivered huge prestige and validated Chief Designer Sergei Korolev’s strategy of using a simple, ultra-light satellite to beat heavier American designs then in development. Globally, it shifted public imagination from aviation to spaceflight overnight, making “satellite” a household word and establishing low-Earth orbit as the first extraterrestrial territory humanity reached. The legal precedent that orbiting overflight was not a violation of national sovereignty underpins today’s open-sky satellite economy, from GPS to weather forecasting.

## Notable For
- First human-made object to orbit any planet
- Smallest and lightest orbital spacecraft until the CubeSat era
- Only Soviet satellite launched by the purpose-built Sputnik rocket (all later missions used modified ICBMs)
- Its 1-watt transmitter required no onboard processor—just a battery and a radio oscillator
- Generated the first tracked orbital decay data, confirming upper-atmosphere density models

## Body
### Design and Construction
Sputnik 1 was a polished aluminium alloy sphere with four 2.4-metre whip antennas folded against its body during launch. Inside were two redundant transmitters, a silver-zinc battery pack, a ventilation system, and a simple fan to regulate temperature. Total mass at liftoff was 83.6 kg, of which 51 kg was hardware and 32 kg battery. The sphere’s high drag coefficient was intentional: it guaranteed rapid decay and avoided adding a retrorocket or long-term debris.

### Launch Profile
The satellite rode atop the M1-PS variant of the R-7 Semyorka ICBM. Liftoff occurred at Site 1/5, Baikonur Cosmodrome (later named Gagarin’s Start). After 295 s of powered flight, the core stage shut down and the payload separated at 7.8 km s⁻¹ into a 215 km × 940 km transfer orbit. Batteries were activated automatically by an inertial switch 56 minutes later when onboard sensors detected free-fall.

### Mission Operations
Ground stations in Crimea and Kamchatka received the 0.3-s beeps on 20.005 MHz, while amateur radio operators worldwide confirmed the signal. Temperature telemetry was encoded by varying the gap between pulses. The last intelligible transmission was received on 26 October 1957 when battery voltage fell below 3 V. Tracking by optical and radio methods allowed refinement of Earth’s oblateness and atmospheric density models.

### Legacy
The mission’s success led directly to Explorer 1 (US, January 1958) and to the formation of NASA in July 1958. The term “Sputnik” entered dozens of languages as a generic word for artificial satellite. Replica flight spares are displayed at the Smithsonian, RKK Energia museum, and the London Science Museum.

## Schema Markup
```json
{
  "@context": "https://schema.org",
  "@type": "Satellite",
  "name": "Sputnik 1",
  "alternateName": ["PS-1", "Prosteyshiy Sputnik-1", "Elementary Satellite 1"],
  "description": "First artificial Earth satellite launched by the Soviet Union in 1957.",
  "sameAs": [
    "https://www.wikidata.org/wiki/Q80802",
    "https://en.wikipedia.org/wiki/Sputnik_1"
  ],
  "manufacturer": {
    "@type": "Organization",
    "name": "S.P. Korolev Rocket and Space Corporation Energia"
  },
  "countryOfOrigin": "Soviet Union",
  "dateCreated": "1957-10-04",
  "weight": {
    "@type": "QuantitativeValue",
    "value": 83.6,
    "unitCode": "kg"
  },
  "width": {
    "@type": "QuantitativeValue",
    "value": 58,
    "unitCode": "cm"
  },
  "additionalProperty": [
    {
      "@type": "PropertyValue",
      "name": "COSPAR ID",
      "value": "1957-001B"
    },
    {
      "@type": "PropertyValue",
      "name": "orbits completed",
      "value": 1440
    }
  ]
}

## References

1. [Sputnik 1. NASA Space Science Data Coordinated Archive](https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1957-001B)
2. Jonathan's Space Report
3. [Alpha Is Science's Tag For First of Satellites. 1957](https://www.nytimes.com/1957/11/25/archives/alpha-is-sciences-tag-for-first-of-satellites.html)
4. [Sputnik 1 Rocket Body. NASA Space Science Data Coordinated Archive](https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1957-001A)
5. Freebase Data Dumps. 2013
6. Czech National Authority Database
7. BBC Things
8. [Source](https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1957-001B)
9. BabelNet
10. [Source](https://golden.com/wiki/Sputnik_1-VWPDK)