# Galaxy Evolution Explorer

> NASA ultraviolet space telescope

**Wikidata**: [Q49944](https://www.wikidata.org/wiki/Q49944)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/GALEX)  
**Source**: https://4ort.xyz/entity/galaxy-evolution-explorer

## Summary
The Galaxy Evolution Explorer (GALEX) was a NASA ultraviolet space telescope launched in 2003 to study the evolution of galaxies. It operated for over a decade, providing critical data on star formation and galaxy evolution before being decommissioned in 2013.

## Key Facts
- **Launched**: April 28, 2003, aboard a Pegasus XL rocket from Cape Canaveral.
- **Decommissioned**: June 28, 2013, after a decade of operation.
- **Mass**: 280 kilograms at takeoff.
- **Dimensions**: 2 meters in length and 2.7 meters in height.
- **Orbit**: Low Earth orbit, with an apogee of 689.478 km and a perigee of 648.261 km.
- **Power**: 290 watts of nominal power output.
- **Mission Duration**: 10 years, 2 months, and 1 day.
- **Predecessor**: Followed the Cosmic Hot Interstellar Plasma Spectrometer (CHIPS) and the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI).
- **Successor**: Preceded the Neil Gehrels Swift Observatory and the Aeronomy of Ice in the Mesosphere (AIM) satellite.
- **Operator**: National Aeronautics and Space Administration (NASA).
- **Manufacturer**: Orbital Sciences Corporation.

## FAQs
### Q: What was the primary mission of GALEX?
A: GALEX was designed to observe galaxies in ultraviolet light, providing insights into star formation, galaxy evolution, and the distribution of stars across the universe.

### Q: How was GALEX launched?
A: GALEX was launched on April 28, 2003, aboard a Pegasus XL rocket from Cape Canaveral Space Force Station Skid Strip.

### Q: What happened to GALEX after its mission ended?
A: GALEX was decommissioned on June 28, 2013, after a decade of operation, having completed its primary mission objectives.

### Q: What type of orbit did GALEX use?
A: GALEX operated in a low Earth orbit, with an apogee of 689.478 km and a perigee of 648.261 km.

### Q: Who operated GALEX?
A: GALEX was operated by the National Aeronautics and Space Administration (NASA) as part of its Small Explorer program.

## Why It Matters
The Galaxy Evolution Explorer played a pivotal role in advancing our understanding of galaxy formation and evolution. By observing ultraviolet light, GALEX provided critical data on star formation rates, the distribution of stars, and the history of galaxies. Its findings contributed to the broader field of astrophysics, helping scientists map the universe's structure and evolution. GALEX's mission also demonstrated the effectiveness of small, focused space telescopes in delivering significant scientific insights. Its legacy continues to influence current and future space-based astronomical observations.

## Notable For
- **First to map ultraviolet light across the sky**: GALEX created the first comprehensive ultraviolet map of the universe, revealing hidden star-forming regions.
- **Discovered new galaxies**: The telescope identified numerous previously unknown galaxies, expanding our catalog of celestial objects.
- **Studied star formation**: GALEX provided detailed observations of star-forming regions, helping scientists understand the lifecycle of stars.
- **Part of NASA's Small Explorer program**: GALEX was a cost-effective mission, demonstrating the value of smaller, targeted space telescopes.
- **Long operational lifespan**: GALEX exceeded its expected mission duration, operating for over a decade and providing continuous data.

## Body
### Mission Overview
The Galaxy Evolution Explorer (GALEX) was a NASA space telescope designed to observe ultraviolet light from galaxies. Launched on April 28, 2003, it was part of NASA's Small Explorer program and operated for over a decade. GALEX's primary mission was to study the evolution of galaxies, star formation, and the distribution of stars across the universe.

### Technical Specifications
GALEX had a mass of 280 kilograms at takeoff and measured 2 meters in length and 2.7 meters in height. It was equipped with a 50-centimeter telescope and two ultraviolet detectors, allowing it to observe light in the far and near ultraviolet bands. The telescope was launched aboard a Pegasus XL rocket from Cape Canaveral Space Force Station Skid Strip.

### Orbit and Operation
GALEX operated in a low Earth orbit, with an apogee of 689.478 km and a perigee of 648.261 km. Its orbital period was approximately 98.4855 minutes, and it had a nominal power output of 290 watts. The telescope's orbital inclination was 28.4855 degrees, and its orbital eccentricity was 0.0003692.

### Scientific Contributions
GALEX made significant contributions to astrophysics, including the creation of the first comprehensive ultraviolet map of the universe. It discovered numerous new galaxies and provided detailed observations of star-forming regions. GALEX's data helped scientists understand the lifecycle of stars and the evolution of galaxies.

### Decommissioning
GALEX was decommissioned on June 28, 2013, after a decade of operation. Its mission was succeeded by the Neil Gehrels Swift Observatory and the Aeronomy of Ice in the Mesosphere (AIM) satellite.

## Schema Markup
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  "@type": "SpaceTelescope",
  "name": "Galaxy Evolution Explorer",
  "description": "NASA ultraviolet space telescope launched in 2003 to study galaxy evolution and star formation.",
  "url": "http://www.galex.caltech.edu/",
  "sameAs": [
    "https://www.wikidata.org/wiki/Q27783",
    "https://en.wikipedia.org/wiki/GALEX"
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  "additionalType": "ArtificialSatellite",
  "launchDate": "2003-04-28",
  "operator": {
    "@type": "Organization",
    "name": "National Aeronautics and Space Administration"
  },
  "manufacturer": {
    "@type": "Organization",
    "name": "Orbital Sciences Corporation"
  },
  "orbit": "Low Earth Orbit",
  "missionDuration": "P10Y2M1D"
}

## References

1. Jonathan's Space Report
2. Freebase Data Dumps. 2013
3. [Source](https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2003-017A)