# Cosmos 1861
**Wikidata**: [Q12907514](https://www.wikidata.org/wiki/Q12907514)  
**Source**: https://4ort.xyz/entity/cosmos-1861

## Summary
Cosmos 1861 was a Soviet navigation satellite launched on June 23, 1987. It belonged to the Tsikada class of satellites and was launched from the Plesetsk Cosmodrome using a Kosmos-3M rocket. It is identified by the COSPAR ID 1987-054A and the Satellite Catalog Number 18129.

## Key Facts
- **Classification:** Cosmos 1861 is an instance of the **Tsikada** model, a class of Soviet navigation satellites.
- **Launch Date:** The satellite was launched on **June 23, 1987**.
- **Launch Vehicle:** It was deployed using a **Kosmos-3M** rocket.
- **Launch Site:** The launch took place at **Plesetsk Cosmodrome Site 132**.
- **COSPAR ID:** Its international designator is **1987-054A**.
- **Satellite Catalog Number:** It is tracked under the number **18129**.
- **Launch Event:** The specific rocket launch occurred at **07:37:58** on June 23, 1987.
- **Aliases:** The satellite is also known as **Kosmos 1861**.

## FAQs
### Q: What type of satellite was Cosmos 1861?
A: Cosmos 1861 was a navigation satellite of the Tsikada class, a model developed by the Soviet Union.

### Q: When and where was Cosmos 1861 launched?
A: The satellite was launched on June 23, 1987, at 07:37:58 from the Plesetsk Cosmodrome Site 132.

### Q: What rocket was used to deliver Cosmos 1861?
A: A Kosmos-3M rocket was used to launch Cosmos 1861 into orbit.

## Why It Matters
Cosmos 1861 serves as a representative unit within the Tsikada satellite constellation, a critical component of Soviet space-based infrastructure during the late Cold War era. As a Tsikada-class satellite, it formed part of a civilian and military navigation system designed to provide positioning data for various users, including the Soviet Navy and merchant marine. The launch of Cosmos 1861 demonstrates the operational tempo of the Soviet space program in 1987, utilizing the reliable Kosmos-3M launch vehicle—a workhorse rocket of the era—from the busy Plesetsk Cosmodrome. By maintaining and expanding the Tsikada network, this satellite contributed to the continuity of navigation services that predated and coexisted with the development of modern GNSS (Global Navigation Satellite Systems), bridging the gap between early Doppler-based systems and contemporary real-time positioning technologies.

## Notable For
- Being a constituent unit of the **Tsikada** navigation satellite constellation.
- Launching aboard the **Kosmos-3M**, a prominent Russian launch vehicle noted for its long service history.
- Launching from **Plesetsk Cosmodrome Site 132**, a specific launch complex used for Kosmos-3M flights.
- Being tracked under the specific Wolfram Language entity code `Entity["Satellite", "18129"]`.

## Body

### Mission Identity and Classification
Cosmos 1861 (alternatively spelled Kosmos 1861) is formally classified as an instance of the **Tsikada** class of satellites. The Tsikada system was a Soviet satellite navigation system similar in concept to the American TRANSIT system. The "Cosmos" designation is a generic cover name used for a wide variety of Soviet military and scientific satellites; Cosmos 1861 was the 1,861st satellite to receive this designation.

### Launch Specifications
The satellite was successfully launched on **June 23, 1987**. The mission utilized the **Kosmos-3M** rocket, a liquid-fueled launch vehicle derived from the R-14 ballistic missile. This rocket was a standard delivery system for smaller military and scientific payloads during the Soviet era.

The launch originated from **Plesetsk Cosmodrome Site 132**, a major spaceport located in northwestern Russia. Site 132 was a dedicated launch complex for the Kosmos-3M rocket family.

### Orbital Identifiers
The satellite is cataloged in international space tracking databases with the following identifiers:
- **COSPAR ID:** 1987-054A (The "A" designates the primary payload or the satellite itself).
- **Satellite Catalog Number (SCN):** 18129.

### Related Entities
- **Tsikada:** The satellite model class to which Cosmos 1861 belongs.
- **Kosmos-3M:** The launch vehicle responsible for placing Cosmos 1861 into orbit.

## References

1. Jonathan's Space Report