Nasa scientists are this morning celebrating the success of their
Deep Impact
mission after a 39-inch-wide projectile fired from a spacecraft struck a comet 83 million miles from Earth.
The space probe hit its comet target early this morning in a mission that scientists hope will reveal clues to how the solar system formed.
It marked the first time a spacecraft touched the surface of a comet, igniting a dazzling fireworks display in space.
The successful strike occurred just before 7am Irish time, according to mission control at Nasa's Jet Propulsion Laboratory in Pasadena, which is managing the $333 million mission.
Scientists at mission control erupted in applause and gave each other hugs as news of the impact spread.
It was a milestone for the US space agency, which hopes that analysis of the cloud of dust and ice thrown out by the explosion will answer basic questions about the origins of the solar system.
The cosmic smash-up did not significantly alter the comet's orbit around the sun and Nasa said the experiment does not pose any danger to Earth
The aim is to smash a lump out of the icy surface of comet Tempel 1, 133 million miles from Earth, to see what lies beneath.
Controllers steered both spacecraft and impactor to the comet from their mission base at Nasa's Jet Propulsion Laboratory in Pasadena, California, 537,000 miles away.
The Deep Impactspacecraft was launched on January 13th from Cape Canaveral, Florida, and has travelled a distance of 431 million kilometres.