Europe's new billion-euro Herschel space observatory, launched in May, has achieved a critical milestone.
The telescope has opened the hatch that has been protecting its sensitive instruments from contamination.
The procedure allowed light collected by Herschel's giant 3.5m mirror to flood its supercold instrument chamber, or cryostat, for the first time.
The observatory's quest is to study how stars and galaxies form, and how they evolve through cosmic time.
The command sent on Sunday to fire two pyrotechnic bolts holding down the hatch was arguably the key moment in the European Space Agency (Esa) mission since the 14 May launch from Earth.
