SOLAR (ISS)
ESA observatory on the ISS measuring solar spectral irradiance.
SOLAR (Solar Monitoring Observatory) was an ESA science observatory mounted on the Columbus Laboratory of the International Space Station. Launched in February 2008 aboard STS-122, it carried three main instruments—SOVIM, SOLSPEC, and SOL-ACES—to provide detailed measurements of the Sun's spectral irradiance. The platform and its instruments were controlled from the Belgian User Support and Operations Centre (B.USOC) in Uccle, Belgium.
- Mission end
- Decommissioned; external platform jettisoned from ISS, re-entry on a different date
Lore & Background
SOLAR was launched with Columbus in February 2008 aboard STS-122 and externally mounted to Columbus alongside the European Technology Exposure Facility (EuTEF). Its three instruments—SOVIM, SOLSPEC, and SOL-ACES—covered a broad spectral range from extreme ultraviolet to infrared. SOVIM measured solar radiation from 200 nanometers to 100 micrometers, building on the earlier SOVA instrument flown in 1992. SOLSPEC measured the 165- to 3000-nanometer range with high spectral resolution, while SOL-ACES used four grazing incidence grating spectrometers to cover the 17- to 220-nanometer EUV/UV regime.
Reader's Guide
SOLAR's significance lies in its decade-long continuous monitoring of the Sun's spectral irradiance from the International Space Station. Originally planned for a 2003 launch, the mission was delayed after the Space Shuttle Columbia disaster. In 2012, the entire 450-tonne station was rotated to allow SOLAR to observe a full solar rotation (24–28 days). The mission ended in 2017 after all but one instrument failed, and the observatory was removed from the station on 28 January 2020, released on 3 February 2020, and burned up over the Pacific Ocean on 13 March 2020. Its data contributed to understanding solar variability and its effects on Earth's climate.
Did You Know?
- In 2012, SOLAR tracked a full solar rotation using the Columbus External Payload Facility's pointing system, without rotating the entire ISS.
- SOLAR's mission ended in 2017 with the failure of all but one of its instruments.
- SOLAR was decommissioned and its external platform was jettisoned from the ISS; re-entry occurred on a different date, not over the Pacific Ocean on 13 March 2020.
Frequently Asked Questions
What is SOLAR (ISS)?
SOLAR, short for Solar Monitoring Observatory, is an ESA scientific instrument package that was bolted onto the Columbus module of the International Space Station. Its core purpose was to record precise measurements of the Sun's spectral irradiance from orbit.
What instruments does SOLAR (ISS) carry?
The observatory houses three primary instruments: SOVIM, SOLSPEC, and SOL-ACES. Together they were designed to capture detailed solar spectral data for scientific analysis.
When and how did SOLAR (ISS) reach the station?
The observatory was launched in February 2008 aboard the Space Shuttle mission STS-122. Once it arrived in orbit, it was installed onto the Columbus Laboratory module for its operational life.
Who controlled SOLAR (ISS) on a day-to-day basis?
Operations were managed by the Belgian User Support and Operations Centre, commonly abbreviated B.USOC, based in Uccle, Belgium. That ground team handled both the platform and its instrument suites.
How did the SOLAR (ISS) mission end?
The observatory was eventually decommissioned, and its external platform was jettisoned away from the station. The jettisoned hardware re-entered Earth's atmosphere on a date separate from the initial release.
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