America kicked off its Independence Day celebrations this morning with an intergalactic fireworks display courtesy of Nasa as a spacecraft smashed into an onrushing comet.

The successful strike 83 million miles (134 million kilometers) away from Earth occurred just before 0700 BST, according to mission control at Nasa’s Jet Propulsion Laboratory in Pasadena, which is managing the US$333 million ($275 million) mission.

Scientists at mission control erupted in applause and hugged each other as news of the impact spread. It was a milestone for the American space agency, which hopes the experiment 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.

A 372kg (820lb) copper bullet, the size of a beer barrel, was dropped yesterday from the spacecraft Deep Impact, which was on collision course with Tempel 1, a lumpy, pickle-shaped comet the size of Manhattan Island that is hurtling through space at 23,000mph.

The high-speed crash, an impact similar to detonating nearly five tonnes of TNT, is the first attempt by the American space agency to glimpse a comet’s core. Scientists believe that comets date from the dawn of the solar system, and getting a first look at their frozen ingredients could provide clues to how the Sun and planets, including Earth, were formed.

They are blobs of ice and dust that orbit the Sun and were formed about four-and-a-half billion years ago, at nearly the same time as the solar system. When a cloud of gas and dust condensed to form the Sun and planets, comets formed from what was left over.

Because they have been frozen, they are largely the same as when they were formed, unlike planets and moons, which have been altered by wind, weather, meteors and volcanoes.

After the impact, as a cloud of ice and dust explodes into space, the mother ship, having staked out a front-row seat 5,000 miles from the collision, began recording the crash and resulting crater with its high-resolution telescope. About 15 minutes later, Deep Impact made its closest fly-by of the comet nucleus, approaching within 310 miles.

The climax of the $333 million (£188 million) mission was also be watched by Nasa’s space-based Hubble, Chandra and Spitzer telescopes. The European Space Agency’s Rosetta spacecraft, on its way to a 2014 rendezvous with a comet, also watched, as did professional astronomers from dozens of observatories in 20 countries.

As the copper probe hurtled towards its target, relying on computers and thrusters to steer itself into the comet’s path, it was expected to beam back pictures of its target in near-real time until moments before its spectacular demise.

Nasa acknowledged the potential problems, not least that the probe could miss. David Spencer, the Deep Impact mission manager, said that the comet is a tiny object in the vastness of space. "It’s a very small target to hit. Plus it’s moving around. It’s not a nice, steady orbit. So it’s a moving target and we have to adjust to hit it."

There was also the chance that the cloud of gas and dust surrounding the comet’s nucleus might damage the spacecraft and probe and prevent data transmissions back to Earth. Deep Impact was launched from Cape Canaveral in Florida on January 12 for its six-month, 268-million-mile voyage. Tempel 1, discovered in 1867, moves around the Sun in an elliptical orbit between Mars and Jupiter every six years or so.

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