# Philae

> robotic European Space Agency lander that accompanied the Rosetta spacecraft

**Wikidata**: [Q1041962](https://www.wikidata.org/wiki/Q1041962)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Philae_(spacecraft))  
**Source**: https://4ort.xyz/entity/philae

## Summary
Philae is a robotic European Space Agency (ESA) lander that accompanied the Rosetta spacecraft. It is designed to descend to and rest on the surface of an astronomical body, specifically the comet 67P/Churyumov–Gerasimenko. The lander operated under the nominal power output of 32 watts and was carried to its destination by the Rosetta spacecraft.

## Key Facts
*   **Classification:** Robotic lander (instance of: lander).
*   **Operator:** European Space Agency (ESA).
*   **Launch Date:** March 2, 2004, at 07:17:51, via an Ariane 5G+ launch vehicle from ELA-3.
*   **Landing Date:** November 12, 2014.
*   **Landing Target:** Comet 67P/Churyumov–Gerasimenko.
*   **Mass:** 97.9 kilograms.
*   **Dimensions:** 1 metre (width) x 1 metre (length) x 0.8 metres (height).
*   **Power:** 32 watts (nominal power output).
*   **Scientific Instruments:** Alpha particle X-ray spectrometer and CONSERT.
*   **Namesake:** Named after the Philae obelisk.

## FAQs
### Q: What was the Philae lander's mission?
A: Philae was a robotic lander designed to accompany the Rosetta spacecraft and descend to the surface of the comet 67P/Churyumov–Gerasimenko. It carried scientific instruments, including an alpha particle X-ray spectrometer and CONSERT, to analyze the comet.

### Q: When and how did Philae land on the comet?
A: Philae undocked from the Rosetta spacecraft on November 12, 2014. It initially touched down at a location named Agilkia at 15:34:04 (Spacecraft Event Time), but its final resting position was at a site named Abydos, where it arrived at 17:31:17.

### Q: What launch vehicle was used to send Philae into space?
A: Philae was launched on March 2, 2004, aboard an Ariane 5G+ rocket (flight V158) from the ELA-3 launch pad. The launch contractor was Arianespace.

## Why It Matters
Philae represents a critical component of the European Space Agency's Rosetta mission, serving as the robotic agent responsible for surface operations on comet 67P/Churyumov–Gerasimenko. While the Rosetta spacecraft acted as the orbiter, Philae was engineered to execute the difficult task of descending onto the comet's surface—a feat requiring precise timing and coordination between the lander and the operations centers (European Space Operations Centre and Microgravity User Support Center).

The lander provides unique data that orbital platforms cannot capture, utilizing tools like its alpha particle X-ray spectrometer to analyze surface composition. The mission timeline highlights the challenges of space exploration; during its landing sequence on November 12, 2014, Philae experienced a complex touchdown involving a bounce. It initially contacted the surface at Agilkia before settling at its final location, Abydos. The mission eventually concluded with a loss of signal on July 9, 2015, marking the end of its operational life on the comet.

## Notable For
*   **Comet Landing:** Successfully completed a soft landing on the comet 67P/Churyumov–Gerasimenko on November 12, 2014.
*   **Complex Touchdown:** Notable for its landing trajectory, which involved an initial touchdown at Agilkia followed by a final stop at Abydos.
*   **Part of Rosetta:** Served as the lander component accompanying the Rosetta spacecraft.
*   **Scientific Payload:** Carried specific instruments designed for in-situ analysis, including the CONSERT experiment and an alpha particle X-ray spectrometer.

## Body
### Mission Profile and Launch
Philae is a robotic lander operated by the European Space Agency (ESA). It was launched on March 2, 2004, at 07:17:51 from the ELA-3 launch site. The launch was conducted by contractor Arianespace using an Ariane 5G+ vehicle (designation V158). Philae traveled to its target attached to the Rosetta spacecraft.

### Technical Specifications
The lander has a mass of 97.9 kilograms. Its physical structure measures 1 metre in width, 1 metre in length, and 0.8 metres in height. The system operates with a nominal power output of 32 watts.

### Landing on 67P/Churyumov–Gerasimenko
The primary objective was to land on the comet 67P/Churyumov–Gerasimenko. The significant event sequence occurred on November 12, 2014:
1.  **Undocking:** Philae separated from the Rosetta spacecraft.
2.  **First Touchdown:** The lander made initial contact with the surface at the Agilkia site at 15:34:04 (Spacecraft Event Time).
3.  **Final Landing:** Philae ultimately came to rest at a location named Abydos at 17:31:17 (Spacecraft Event Time).

### Operations and End of Mission
Upon landing, Philae utilized its scientific instruments, including the alpha particle X-ray spectrometer and CONSERT, to conduct analysis. The mission encountered challenges regarding communication and power. A significant loss of signal event occurred on July 9, 2015, at 18:07, effectively ending the operational phase of the lander.

### Nomenclature and Identifiers
The lander is named after the Philae obelisk. It is identified by the COSPAR ID 2004-006C and the NSSDCA ID 2004-006C. It is also referred to as "Rosetta Lander" in various contexts.

## References

1. Jonathan's Space Report
2. [No. 1 - Rosetta in Good Health - Rosetta - Science Portal](https://sci.esa.int/web/rosetta/-/34797-rosetta-status-report-no-1/)
3. [Did Philae graze a crater rim during its first bounce? – Rosetta – ESA's comet chaser](https://blogs.esa.int/rosetta/2014/11/28/did-philae-graze-a-crater-rim-during-its-first-bounce/)
4. Freebase Data Dumps. 2013
5. BBC Things
6. The Rosetta Lander (“Philae”) Investigations