# SSTL-S1 1

> Earth observation satellite

**Wikidata**: [Q111471588](https://www.wikidata.org/wiki/Q111471588)  
**Source**: https://4ort.xyz/entity/sstl-s1-1

## Summary
SSTL-S1 1, also known as DMC 3-FM1 or TripleSat 1, is a British Earth observation satellite manufactured by Surrey Satellite Technology. Launched on July 10, 2015, it operates as part of the UK-DMC 3 trio, a group of three imaging satellites funded by the Chinese company 21AT. The satellite orbits the Earth in a sun-synchronous path to provide continuous observational data.

## Key Facts
- **Classification:** Earth observation satellite (artificial satellite specifically designed to observe Earth from orbit).
- **Launch Date:** July 10, 2015, at 16:28.
- **Launch Vehicle:** Polar Satellite Launch Vehicle-XL (specifically the PSLV-C28 variant).
- **Launch Site:** Satish Dhawan Space Centre First Launch Pad.
- **Manufacturer:** Surrey Satellite Technology (United Kingdom).
- **Operator:** DMC International Imaging.
- **Mass:** 447 kilograms (launch weight).
- **Orbit:** Sun-synchronous orbit.
- **Funder:** 21AT (a Chinese firm).
- **Spacecraft Bus:** SSTL-300.
- **COSPAR ID:** 2015-032A.
- **Aliases:** DMC 3-FM1, UK-DMC3A, DMC-3 1, TripleSat 1, Beijing 2-1, DMC3-1.

## FAQs
### Q: What is the SSTL-S1 1 satellite used for?
A: SSTL-S1 1 is an Earth observation satellite designed to capture images of the planet from orbit. It is part of a trio of satellites that provide commercial imaging services.

### Q: Who manufactured and operates SSTL-S1 1?
A: The satellite was manufactured by Surrey Satellite Technology in the United Kingdom and is operated by DMC International Imaging.

### Q: How was SSTL-S1 1 launched into space?
A: The satellite was launched on July 10, 2015, aboard a Polar Satellite Launch Vehicle-XL (PSLV-C28) from the Satish Dhawan Space Centre First Launch Pad.

## Why It Matters
SSTL-S1 1 is a significant component of the UK-DMC 3 (Disaster Monitoring Constellation) trio, which represents a notable collaboration in the commercial space sector. While manufactured in the United Kingdom by Surrey Satellite Technology, the constellation was funded by the Chinese company 21AT (Twenty First Century Aerospace Technology), highlighting the international nature of modern satellite deployment.

The satellite plays a critical role in Earth observation, utilizing the SSTL-300 bus to maintain a sun-synchronous orbit. This orbit allows the satellite to pass over the same point on Earth at roughly the same local time each day, ensuring consistent lighting conditions for imaging. Weighing 447 kg at launch, the satellite contributes to global monitoring capabilities, supporting the collection of high-fidelity data for commercial and potentially environmental analysis. Its deployment via the Indian PSLV-C28 also underscores the reliance on multi-national launch capabilities for complex satellite constellations.

## Notable For
- **Constellation Member:** Being one of three identical satellites (along with SSTL-S1 2 and SSTL-S1 3) forming the UK-DMC 3 group.
- **International Funding:** A UK-built satellite fully funded by a Chinese firm, 21AT, marketed as the "TripleSat" constellation.
- **Imaging Capability:** Designed to provide high-resolution Earth observation data.
- **Launch Configuration:** Launched as part of a dedicated commercial mission (PSLV-C28) carrying multiple satellites.

## Body

### Technical Specifications
SSTL-S1 1 has a launch mass of 447 kilograms. It is built on the **SSTL-300 spacecraft bus**, a platform developed by Surrey Satellite Technology. The satellite is designed to operate in a **sun-synchronous orbit**, a low Earth orbit that allows it to maintain a constant angle of solar illumination, which is optimal for consistent Earth imaging.

### Launch and Deployment
The satellite was successfully launched on **July 10, 2015**, at 16:28 UTC. The launch was executed from the **Satish Dhawan Space Centre First Launch Pad** in India. The vehicle used was the **Polar Satellite Launch Vehicle-XL** (flight designation PSLV-C28). This launch event is recorded as a significant rocket launch event in the satellite's operational timeline.

### Organizational Structure
- **Country of Origin:** United Kingdom.
- **Manufacturer:** Surrey Satellite Technology.
- **Funder:** 21AT (Twenty First Century Aerospace Technology).
- **Operator:** DMC International Imaging.

### Identification and Nomenclature
The entity is officially cataloged under the **COSPAR ID 2015-032A** and the **NORAD SCN 40715**. It is known by several aliases due to its role in different organizational frameworks, including **DMC 3-FM1** (referring to its position in the DMC), **TripleSat 1** (the commercial name used by 21AT), and **Beijing 2-1**.

## References

1. [Source](https://space.skyrocket.de/doc_sdat/uk-dmc-3.htm)
2. Jonathan's Space Report
3. [Source](https://spacenews.com/surrey-build-three-optical-imaging-satellites-chinese-firm/)