European astronauts have arrived in Edinburgh to have training from scientists at the University.
The visitors from the European Space Agency will undergo training in astrobiology to understand how to collect samples during planetary missions, to minimise contamination.
They will also learn how to collect appropriate samples that can be used to search for habitable conditions elsewhere and maybe even life.
They will be given lectures in the subject and carry out laboratory work, in addition to using Arthur's Seat in the city centre to learn about geology and how to select samples for further study.
The astronauts' training will include how to search for signs of life in rocks and how to analyse geological samples in the lab.
Taking part are Mathias Maurer, who joined ESA in 2010 and is scheduled to complete his basic astronaut training this year.
His experience includes spending 16 days underwater to test hardware and experiments for the International Space Station, as well as testing exploration strategies and tools for future missions to Mars.
He will be joined by Pedro Duque, who has worked on many space missions with ESA and NASA, and qualified for one of the first European long-term missions to the International Space Station.
His spaceflight experience includes a nine-day mission on the Space Shuttle Discovery, and the 10-day Cervantes mission on the International Space Station.
Their visit forms part of the ESA's Pangaea course, which is designed to provide European astronauts with introductory and practical knowledge of Earth and planetary geology.
The course is intended to prepare astronauts to effectively partner planetary scientists and engineers in designing exploration missions.
It is also intended to give astronauts a solid knowledge in the geology of the Solar System by learning from leading European scientists.
Professor Charles Cockell of the School of Physics and Astronomy, and head of the UK Centre for Astrobiology, leads the ESA astronaut training in astrobiology and geomicrobiology.
We are really excited to be sharing our knowledge and expertise with European astronauts, in a visit which puts us at the forefront of future human exploration missions beyond Earth and introduces Europe's new astronauts to science relevant for their future work.