# SELENE

> former Japanese lunar orbiter spacecraft

**Wikidata**: [Q205408](https://www.wikidata.org/wiki/Q205408)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/SELENE)  
**Source**: https://4ort.xyz/entity/selene

## Summary
SELENE (Selenological and Engineering Explorer), also known as Kaguya, was a Japanese lunar orbiter spacecraft operated by the Japan Aerospace Exploration Agency (JAXA). Launched on September 14, 2007, the spacecraft conducted scientific operations from a polar orbit before concluding its mission with a controlled lunar impact on June 10, 2009. It remains a significant entity in Japan's space exploration history.

## Key Facts
- **Formal Name:** Selenological and Engineering Explorer (nicknamed **Kaguya**).
- **Operator:** Japan Aerospace Exploration Agency (JAXA).
- **Launch Date:** September 14, 2007, at 01:31:01 UTC.
- **Launch Vehicle:** H-IIA (specifically H-IIA-13 variant).
- **Launch Site:** Yoshinobu Launch Complex Launch Pad 1.
- **Mass:** 2,914 kilograms.
- **Orbital Specifications:** Maintained an orbit with an apoapsis and periapsis of 100 kilometres and an inclination of 90 degrees.
- **Mission End:** June 10, 2009 (controlled lunar impact).
- **Components:** The spacecraft included two sub-satellites named **Okina** and **Ouna**.

## FAQs
### Q: What was the SELENE (Kaguya) mission?
A: SELENE was a former Japanese lunar orbiter designed to orbit the Moon. It was operated by the Japan Aerospace Exploration Agency to gather selenological and engineering data.

### Q: When did SELENE launch and how long was it operational?
A: The spacecraft launched on September 14, 2007, and operated until its mission termination via lunar impact on June 10, 2009.

### Q: What rocket was used to launch SELENE?
A: SELENE was launched using an H-IIA expendable medium-lift launch vehicle, specifically the H-IIA-13 configuration, from the Yoshinobu Launch Complex.

## Why It Matters
SELENE represents a critical milestone in the "Selenological and Engineering Explorer" lineage, serving as Japan's dedicated effort in lunar observation. As a heavy spacecraft weighing nearly 3,000 kilograms, it required the robust capabilities of the H-IIA launch vehicle, demonstrating Japan's technical proficiency in medium-lift space deployment. The mission is distinguished by its inclusion of two distinct sub-components, Okina and Ouna, indicating a complex mission architecture designed to relay data and measure the Moon's gravity field and environment from a precise 100-kilometer polar orbit.

The successful execution of the launch on September 14, 2007, and the controlled lunar impact conclusion on June 10, 2009, provided a complete dataset that contributes to the global understanding of lunar topography and environment. The mission's precise orbital parameters—a 90-degree inclination and a circular 100-kilometer altitude—allowed for consistent observation of the lunar surface. Its identification numbers (COSPAR 2007-039A) and archival status as a "former entity" ensure its data remains a permanent fixture in astronomical databases.

## Notable For
- **Multi-Satellite Architecture:** Unlike standard orbiters, SELENE deployed or contained specific sub-units named **Okina** and **Ouna** to enhance its scientific capabilities.
- **Precise Orbital Profile:** It maintained a circular polar orbit (90-degree inclination) at exactly 100 kilometres altitude, allowing for uniform surface coverage.
- **High Mass Specifications:** Weighing 2,914 kilograms, it was a substantial scientific payload requiring significant power consumption (3,486 watts).
- **Naming Heritage:** The mission carried the nickname "Kaguya," referencing Japanese folklore, alongside its technical title SELENE.

## Body

### Launch and Deployment
SELENE was launched by the Japan Aerospace Exploration Agency on **September 14, 2007**. The launch took place at precisely 01:31:01 from the **Yoshinobu Launch Complex Launch Pad 1**. The vehicle used to propel the 2,914 kg spacecraft was the **H-IIA**, specifically the H-IIA-13 variant, a Japanese expendable medium-lift launch vehicle.

### Technical Specifications
The spacecraft was designed to operate with a power consumption of **3,486 watts**. It utilized a specific orbital configuration to achieve its scientific goals:
- **Apoapsis:** 100 kilometres
- **Periapsis:** 100 kilometres
- **Orbital Inclination:** 90 degrees (polar orbit)
- **Orbital Period:** 2 hours

SELENE was not a solitary unit; the system included distinct parts identified as **Okina** and **Ouna**.

### Mission Conclusion
The spacecraft's operational life ended via a planned **lunar impact**. This event occurred on **June 10, 2009**. Following the impact, the entity is classified as a "former entity" located on the astronomical body of the **Moon**, specifically within the lunar quadrangle **LQ30**.

### Identifiers and Cataloguing
The spacecraft is catalogued under multiple international identifiers:
- **COSPAR ID:** 2007-039A
- **NAIF ID:** -131
- **Wikipedia Title:** SELENE
- **Commons Category:** SELENE (spacecraft)

## References

1. Jonathan's Space Report
2. Freebase Data Dumps. 2013
3. [Source](https://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/req/naif_ids.html)