# Uhuru

> first satellite launched specifically for the purpose of X-ray astronomy

**Wikidata**: [Q580043](https://www.wikidata.org/wiki/Q580043)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Uhuru_(satellite))  
**Source**: https://4ort.xyz/entity/uhuru

## Summary
Uhuru, also known as Explorer 42 or the X-ray Small Astronomical Satellite 1, was the first satellite launched specifically for the purpose of X-ray astronomy. Operating as a space telescope, it was launched into orbit on December 12, 1970, and remained operational until its atmospheric re-entry in April 1979.

## Key Facts
- **Primary Identity:** First satellite dedicated specifically to X-ray astronomy.
- **Also Known As:** Explorer 42; X-ray Small Astronomical Satellite 1.
- **Launch Date:** December 12, 1970.
- **Launch Vehicle:** Scout B rocket.
- **Launch Site:** Broglio Space Centre.
- **Mass:** 141.5 kilograms.
- **Orbital Period:** 96 minutes.
- **Mission End:** Atmospheric entry occurred on April 5, 1979.
- **COSPAR ID:** 1970-107A.
- **Official Website:** [heasarc.gsfc.nasa.gov/docs/uhuru/uhuru.html](https://heasarc.gsfc.nasa.gov/docs/uhuru/uhuru.html)

## FAQs
### Q: What was the primary purpose of the Uhuru satellite?
A: Uhuru was the first satellite launched specifically for the purpose of X-ray astronomy. It functioned as a space telescope designed to observe distant space objects in the X-ray spectrum.

### Q: When was Uhuru launched and how long did it stay in orbit?
A: Uhuru was launched on December 12, 1970. It remained in orbit for over eight years, finally re-entering the atmosphere on April 5, 1979.

### Q: What rocket was used to launch Uhuru and where did it launch from?
A: The satellite was launched aboard a Scout B rocket from the Broglio Space Centre.

## Why It Matters
Uhuru represents a critical milestone in the history of astrophysics and space exploration. As the first satellite explicitly designed for X-ray astronomy, it marked the transition from brief, rocket-based observations of the sky to sustained, satellite-based monitoring of X-ray sources. Before Uhuru, X-ray observations were limited to brief moments of rocket flights above the atmosphere; Uhuru allowed for the continuous scanning of the sky, fundamentally changing how astronomers observed high-energy phenomena.

The mission provided the first comprehensive view of the X-ray sky, allowing for the cataloging of sources that were invisible to optical telescopes. By operating for over eight years (1970–1979), it demonstrated the viability of long-term automated observatories in low Earth orbit. Its success paved the way for future high-energy astrophysics missions, establishing the methodology for mapping and analyzing cosmic X-ray emissions.

## Notable For
- Being the **first satellite** launched specifically for the purpose of X-ray astronomy.
- Operating as the **first** in the series of Small Astronomical Satellites (SAS-1).
- Having a **long operational lifespan** for an early observatory, spanning from 1970 to 1979.
- Launching from the **Broglio Space Centre** (San Marco Equatorial Range), an early example of an offshore launch platform.
- Providing the first all-sky survey of X-ray sources.

## Body
### Mission Specifications
Uhuru was classified as a **space telescope** designed for observing distant space objects. Weighing **141.5 kilograms**, it was a compact but powerful instrument for its time. It was placed into an orbit with a period of **96 minutes**, allowing it to scan the sky efficiently as the Earth rotated beneath it.

### Launch and Deployment
The satellite was launched on **December 12, 1970**, utilizing a **Scout B** rocket model. The launch originated from the **Broglio Space Centre**. This specific launch vehicle and site combination was utilized for the mission designated **1970-107A** (COSPAR ID).

### Operational History and Decay
Following its successful deployment, Uhuru conducted operations for nearly a decade. The mission concluded when the satellite underwent uncontrolled **atmospheric entry**. This significant event occurred on **April 5, 1979**, marking the end of the satellite's functional life and physical existence.

### Alternative Designations
The satellite is identified by several names and identifiers in academic and agency records:
*   **Explorer 42**
*   **X-ray Small Astronomical Satellite 1**
*   **NSSDCA ID:** 1970-107A
*   **Satellite Catalog Number (SCN):** 04797

## References

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