All the international partners had to agree on changing the ISS's orientation.
However, moving a 450-ton orbital outpost the size of a city block isn't a simple undertaking. Aside from calculating the correct orbit to keep SOLAR in view of the sun, other factors need to be taken into account such as ensuring the solar panels that power the Station also face the sun. Additionally, communication antennas need to be reoriented to stay in contact with Earth and other scientific experiments must be adjusted.
The SOLAR instrument was originally designed to last about 18 months, but has been going strong for 5 years. It is installed on the outside of the ESA's Columbus module.
The SOLAR payload consists of three instruments to the solar spectral irradiance throughout virtually the whole electromagnetic spectrum.
The three complementary solar science instruments are:
SOVIM (SOlar Variable and Irradiance Monitor), which covers near-UV, visible and thermal regions of the spectrum.
SOLSPEC (SOLar SPECctral Irradiance measurements) covers the 180 nm – 3 000 nm range.
SOL-ACES (SOLar Auto-Calibrating Extreme UV/UV Spectrophotometers) measures the EUV/UV spectral regime.
Scientists say SOLAR's observations are improving our understanding of the sun and allowing scientists to create accurate computer models and predict its behavior.