Investigations into solar irradiance at high altitude have been undertaken as part of the Return to Everest 2009 expedition. The trek crew, which included Keith Cowing, Miles O'Brien, NASA astronaut Scott Parazynski, and others, used the Jaz spectrometer from Ocean Optics to determine UV intensity levels in the Everest region where levels are typically extremely high. The handheld Jaz unit that accompanied the group included solar irradiance scripting language, an SD card for storage of spectra and Jaz’s lithium-ion battery.
The participants used Jaz to measure solar irradiance with a focus on UV levels at an extreme altitude. It is suggested that UV levels on Everest should be among the highest on Earth and Jaz was used to perform analysis of the nature of the sunlight during the experiment phase of the summit. The expedition was completed successfully on 25 May.