# ICESat

> former satellite in NASA's Earth Observing System

**Wikidata**: [Q50019](https://www.wikidata.org/wiki/Q50019)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/ICESat)  
**Source**: https://4ort.xyz/entity/icesat

## Summary
ICESat (Ice, Cloud, and land Elevation Satellite) was a NASA Earth observation satellite launched in 2003 to measure ice sheet mass balance, cloud and aerosol heights, as well as land topography and vegetation characteristics. It operated until 2010, when it was decommissioned and re-entered Earth's atmosphere.

## Key Facts
- Launched on January 13, 2003, at 00:45 UTC from Vandenberg Space Launch Complex 2 West using a Delta II rocket (D-294)
- Operated by the National Aeronautics and Space Administration (NASA)
- Carried the Geoscience Laser Altimeter System (GLAS) as its primary scientific instrument
- Had a mass of 970 kg and used a BCP-2000 spacecraft bus
- Powered by a photovoltaic system
- Service entry occurred on February 20, 2003
- Experienced a GLAS breakdown on October 11, 2009
- Service retirement was on August 14, 2010, at 17:37 UTC
- Atmospheric entry occurred on August 30, 2010, at 08:49 UTC
- NORAD catalog number: 27642
- COSPAR ID: 2003-002A
- Manufacturer: Ball Aerospace & Technologies

## FAQs
### Q: What was the primary mission of ICESat?
A: ICESat's primary mission was to measure ice sheet mass balance, cloud and aerosol heights, as well as land topography and vegetation characteristics using its Geoscience Laser Altimeter System (GLAS).

### Q: How long did ICESat operate in space?
A: ICESat operated for approximately 7 years, from its launch on January 13, 2003, until its decommissioning on August 14, 2010.

### Q: What happened to ICESat after it stopped functioning?
A: After service retirement in August 2010, ICESat was decommissioned and re-entered Earth's atmosphere on August 30, 2010.

## Why It Matters
ICESat represented a significant advancement in Earth observation technology, providing unprecedented measurements of polar ice sheets, sea ice thickness, and vegetation canopy heights. Its laser altimetry data helped scientists understand changes in Earth's ice cover and contributed to climate change research. The satellite's measurements were crucial for monitoring ice sheet mass balance, which is essential for predicting sea level rise. ICESat's data also improved our understanding of cloud properties and aerosol distribution in the atmosphere. The mission demonstrated the effectiveness of space-based laser altimetry for Earth science applications and paved the way for its successor, ICESat-2, which continues this important work with enhanced capabilities.

## Notable For
- First satellite mission specifically designed to measure ice sheet elevation changes using laser altimetry
- Provided the first space-based measurements of ice sheet elevation changes over time
- Generated the first global measurements of cloud and aerosol heights from space
- Created detailed maps of Earth's vegetation canopy heights
- Established a baseline dataset for monitoring polar ice sheet changes and their contribution to sea level rise

## Body
### Mission Overview
ICESat was part of NASA's Earth Observing System, designed to provide precise measurements of Earth's surface elevation using laser technology. The satellite's primary instrument, the Geoscience Laser Altimeter System (GLAS), was a space-based LIDAR that emitted infrared and visible laser pulses to measure distances to Earth's surface.

### Technical Specifications
The satellite had a mass of 970 kg and was built on a BCP-2000 spacecraft bus. It was powered by a photovoltaic system consisting of solar panels. The spacecraft was manufactured by Ball Aerospace & Technologies and launched aboard a Delta II rocket (D-294) from Vandenberg Air Force Base.

### Scientific Instruments
The Geoscience Laser Altimeter System (GLAS) was ICESat's sole scientific instrument. It operated in two wavelengths: 1064 nm (infrared) and 532 nm (visible green). The instrument could measure elevation changes as small as 1.5 cm over areas of 100 m diameter.

### Mission Timeline
- Launch: January 13, 2003, at 00:45 UTC
- Service entry: February 20, 2003
- GLAS breakdown: October 11, 2009
- Service retirement: August 14, 2010
- Atmospheric entry: August 30, 2010

### Scientific Contributions
ICESat provided critical data for understanding:
- Changes in polar ice sheet elevation and mass balance
- Sea ice thickness and distribution
- Cloud and aerosol properties
- Vegetation canopy heights
- Topographic mapping of previously unmapped regions

### Legacy
The success of ICESat led to the development of ICESat-2, launched in 2018, which continues the mission with improved technology and higher measurement resolution. The data collected by ICESat remains valuable for long-term climate studies and continues to be used by researchers worldwide.

## References

1. [Source](https://www.defense-aerospace.com/articles-view/release/3/17302/icesat-tested%2C-commissioned.html)
2. Jonathan's Space Report
3. [Source](https://www.space-track.org/basicspacedata/query/class/tip/NORAD_CAT_ID/27642/orderby/ID%20DESC/format/html/)
4. Freebase Data Dumps. 2013
5. [Source](https://glas.wff.nasa.gov/)
6. [Source](https://spaceflightnow.com/news/n1002/25icesat/)