A Nasa probe sent to collect rock from an asteroid several hundred million kilometres from Earth has grabbed so much that samples are spilling out.
Officials behind the Osiris-Rex probe, which landed on Bennu earlier this week, say the collection operation may have performed too well.
Pictures beamed back to Earth show a rock has wedged open the door of a container and a fraction of the sample is leaking, Nasa says.
Nasa is now trying to stow it safely.
"A substantial fraction of the required collected mass is seen escaping," head of mission Dante Lauretta said.
The craft is believed to have collected some 400g (14oz) of fragments, he said.
The probe could not have done better, he added. "My big concern now is that the particles are escaping because we were almost a victim of our own success here."
"Time is of the essence," Thomas Zurbuchen, Nasa's associate administrator for science, told reporters as the space agency focuses on making sure no more is lost.