Columbus external payloads SOLAR and EuTEF were installed during the STS-122 mission a few days after the Columbus laboratory was attached to the International Space Station.
The European Technology Exposure Facility (EuTEF), a programmable, fully automated, multi-user facility with modular and flexible accommodation for a variety of technology payloads, was mounted outside the Columbus module. It carried experiments requiring exposure to the space environment and was returned to Earth in September 2009 aboard Space Shuttle Discovery on mission STS-128.
SOLAR, studies the Sun with unprecedented accuracy across most of its spectral range. This is currently scheduled to last two years. SOLAR is located on the Columbus External Payload Facility zenith position (i.e. pointing away from the Earth).