NASA launched a spacecraft on Wednesday shouldering the mission to crash a hole in a comet in order to give scientists a glimpse at the frozen primordial features of the solar system.

The Delta 2 rocket lifted off from Cape Canaveral Air Force Station as planned at 1:47 p.m. EST (1:47 p.m. EST) with a spacecraft the size of a small car tucked inside its nose cap.

The probe, with a Hollywood name Deep Impact, was put on a path to blow a football stadium-sized crater in Comet Tempel 1 on July 4 more than 82 million miles from Earth.

"We have ignition and liftoff of a Delta 2 rocket, carrying Deep Impact - NASA's journey to unlock the mystery of the solar system's origin," said NASA launch commentator Jessica Rye.

"The key goal of Deep Impact is to relate all these measurements of the surface material to what the deep interior material is, (material) which is preserved from the beginning of the solar system," said Jay Melosh, a University of Arizona researcher and a mission co-investigator.

While most space probes passively study the cosmos or conduct microscopic tests, Deep Impact will experiment with a planetary body itself. Scientists find comets inviting because their frozen cores contain pristine samples of materials used in the formation of the universe.

Scientists are counting on Deep Impact to carve out a crater that could swallow the Roman Coliseum. It will be humanity's first look into the heart of a comet, a celestial snowball still containing the original building blocks of the sun and the planets.

"Comets are the most primitive bodies in our solar system, and they are made up of the very material from which the planets and the sun, in fact, are made," said Andrew Dantzler, director of the solar system division at NASA headquarters, in a televised press briefing yesterday.

Exposing a comet's core is no easy task. Not only are comets relatively small - Tempel 1, for example is believed to be about five to nine miles long and about one-third that in diameter - they are moving very quickly.

Deep Impact, for example, will have to blast across space at 6.2 miles per second to overtake comet Temple 1, drop off a stubby-nosed, copper-capped projectile in its path and scramble to a safe distance to observe the mega-explosion.

Still, principal investigator Mike A'Hearn said simulations give the team more than a 99.9 percent chance of a good hit.

The information is expected to help answer some basic questions about the formation of the solar system, including what role comet impacts played in the development of Earth.

"We know comets delivered water," said A'Hearn. "but what else?"

Source: Xinhua