A telescope on a mission to hunt for black holes using X-rays has been blasted into space, Nasa said.
The Nuclear Spectroscopic Telescope Array, which is nicknamed NuStar, was launched from a carrier plane above the Pacific ocean before free-falling for five seconds and launching its rocket into space.
It has now been successfully placed into orbit, Nasa said in a press release.
Because the telescope can see through gas and dust, it could reveal hidden black holes at the heart of distant galaxies.
Scientists think that 'super-massive black holes' exist at the centre of most, if not all, galaxies - but because of the dust and other material surrounding those areas it can be difficult to prove.
By studying X-rays, NuStar should be able to peer through the murk and find out what is hiding behind it.
Nasa said it will "open a new window on the universe".
"NuStar will help us find the most elusive and most energetic black holes, to help us understand the structure of the universe," said Fiona Harrison, the mission's principal investigator at the California Institute of Technology in Pasadena.
The telescope has a unique design, including a 33-foot mast which was folded into a very small payload during the rocket's launch.
It will take 23 days to unfold the mast, check the systems and begin the experiments, which will last for about two years.
NuStar will study many other objects in the universe, including the remains of supernovas (exploded stars) and clusters of faraway galaxies.
"The mission's observations, in coordination with other telescopes such as Nasa's Chandra X-ray Observatory, which detects lower-energy X-rays, will help solve fundamental cosmic mysteries," Nasa said. NuStar also will study our sun's fiery atmosphere, looking for clues as to how it is heated."