# Arabsat-1B

> derelict Saudi Arabian communications satellite

**Wikidata**: [Q4783491](https://www.wikidata.org/wiki/Q4783491)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Arabsat-1B)  
**Source**: https://4ort.xyz/entity/arabsat-1b

## Summary
Arabsat-1B was a Saudi Arabian geostationary communications satellite launched on June 17, 1985, aboard the Space Shuttle Discovery. Manufactured by Aérospatiale and Messerschmitt-Bölkow-Blohm, it operated as part of the Arabsat fleet before becoming derelict due to attitude control failures in the early 1990s. It was succeeded by the Indian satellite INSAT-2DT.

## Key Facts
- **Entity Type:** Derelict Saudi Arabian communications satellite and geostationary satellite.
- **Launch Date:** June 17, 1985 (11:33:00 UTC).
- **Launch Vehicle:** Space Shuttle Discovery (STS-51-G mission), utilizing a PAM-D space tug.
- **Manufacturer:** Aérospatiale and Messerschmitt-Bölkow-Blohm (Country of origin: France).
- **Mass:** 1,270 kg (launch weight); 592 kg (service entry weight).
- **Designators:** COSPAR ID 1985-048C; SATCAT 15825.
- **Service Life:** Designed for 7 years; suffered failure in October 1992 and breakdown in 1993.
- **Orbit:** Geostationary orbit.
- **Operator:** Arab Satellite Communications Organization.

## FAQs
### Q: How was Arabsat-1B launched?
A: Arabsat-1B was launched from Kennedy Space Center Launch Complex 39A on June 17, 1985. It was deployed into space by the Space Shuttle Discovery during the STS-51-G mission.

### Q: What happened to Arabsat-1B?
A: The satellite experienced an attitude control failure in October 1992, followed by a further breakdown in 1993. These events rendered the satellite nonfunctional, classifying it as a derelict satellite remaining in orbit.

### Q: What satellite replaced Arabsat-1B?
A: Arabsat-1B was succeeded by INSAT-2DT, a decommissioned Indian geostationary communications satellite that was formerly operated by Saudi Arabia to maintain communications capabilities.

## Why It Matters
Arabsat-1B serves as a significant case study in the history of international space cooperation and commercial satellite operations in the 1980s. As part of the early Arabsat fleet, it represented an effort by the Arab Satellite Communications Organization to establish independent telecommunications infrastructure across the region. Technically, the satellite highlights the reliance on Space Shuttle deployments for commercial payloads during this era, utilizing the PAM-D upper stage to reach geostationary orbit.

The satellite's history also illustrates the challenges of long-term space operations. Despite a design life of 7 years, the spacecraft encountered critical attitude control failures roughly 7 years into its mission, transitioning from an operational asset to space debris. Furthermore, its succession by INSAT-2DT—an Indian satellite leased by Saudi Arabia—demonstrates the strategic practice of transferring orbital responsibilities to maintain spectrum rights and service continuity when primary assets fail.

## Notable For
- **Shuttle Deployment:** Being deployed by the Space Shuttle *Discovery* (STS-51-G), a characteristic launch method for commercial satellites of the mid-1980s.
- **Dual Mass Specifications:** Having a distinct launch weight of 1,270 kg and a service entry weight of 592 kg.
- **International Manufacturing:** Being a French-built satellite (Aérospatiale/MBB) operated by a Saudi Arabian organization.
- **Cross-Border Succession:** Being succeeded in its operational role by INSAT-2DT, a satellite of Indian origin.

## Body

### Development and Specifications
Arabsat-1B was built using the **Spacebus-1000** spacecraft bus. Constructed by the French firm **Aérospatiale** and the German company **Messerschmitt-Bölkow-Blohm**, the satellite had a country of origin listed as France.

The satellite's physical specifications included:
- **Launch Weight:** 1,270 kilograms.
- **Service Entry Weight:** 592 kilograms.
- **Power System:** Powered by two spacecraft solar arrays generating 1,400 watts, supplemented by an R-4D engine.

Designed for a lifespan of 7 years, the satellite served as a telecommunications platform in **geostationary orbit**.

### Launch and Deployment
Arabsat-1B was launched on **June 17, 1985**, at 11:33:00 UTC. The launch originated from **Kennedy Space Center Launch Complex 39A**. It was a payload on the **Space Shuttle Discovery** (mission STS-51-G). To achieve its final orbit, the satellite utilized a **PAM-D** (Payload Assist Module) space tug.

### Operational Timeline and End of Life
Following its launch, Arabsat-1B operated under the **Arab Satellite Communications Organization**. It was the second satellite in the program, following **Arabsat-1A**.

The satellite's operational status degraded in the early 1990s:
- **October 1992:** The satellite suffered a failure related to attitude control.
- **1993:** The satellite experienced a total breakdown.

These events left the satellite nonfunctional and derelict in orbit. To replace its capacity, the satellite was succeeded by **INSAT-2DT**, which had previously operated under different designations before being utilized by Saudi Arabia.

## Schema Markup
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  "@type": "Thing",
  "name": "Arabsat-1B",
  "description": "A derelict Saudi Arabian geostationary communications satellite launched in 1985 by the Space Shuttle Discovery.",
  "identifier": "1985-048C",
  "sameAs": [
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  "additionalType": "Communications Satellite"
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## References

1. [Source](https://space.skyrocket.de/doc_sdat/arabsat-1a.htm)
2. Jonathan's Space Report
3. [Source](http://www.tbs-satellite.com/tse/online/sat_arabsat_1b.html)
4. [Source](https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1985-048C)