NASA launches ‘Messenger’ to Mercury

NASA launches ‘Messenger’ to Mercury

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The NASA has launched ‘Messenger’ spacecraft on the first mission to Mercury beginning a seven year and 5 billion-mile journey to head to the suns closest planet in 30 years.

The $286 million, 2,442-pound satellite was launched at about 2.15 am local time (0616 GMT) on Tuesday aboard a Boeing Co. Delta II rocket from the Cape Canaveral Air Force Station in Florida on a seven-year journey to the closest planet to the sun.

It will be the first mission to Mercury since ‘Mariner 10’ visited in 1974 and 1975. The liftoff followed a delay on Monday due to “weather constraints.”

‘Messenger’ is a scientific investigation of the planet Mercury. Understanding Mercury, and the forces that have shaped it, is fundamental to understanding the terrestrial planets and their evolution.

The spacecraft will orbit Mercury following three flybys of that planet. The orbital phase will use the flyby information as an initial guide to perform a focused scientific investigation of this mysterious world.

Among the questions scientists hope to answer is whether Mercury, just slightly larger than Earth’s moon, was once Earth-sized itself but lost its rocky exterior either to some cataclysmic collision or to slow ablation by the solar winds.

Scientists also believe there may be frozen water there, trapped in shadowy craters at the planets poles, never exposed to the sunlight that creates a 1100 degF difference between daytime and nighttime temperatures on the planet.

“The inner planets (Mercury, Venus, Earth and Mars) all formed from the disk of gas and dust, the solar nebula, that surrounded our young sun. They formed by the same processes, the same time, but their outcomes were extremely different. And Mercury is the most extreme of these four planets,” said Sean Solomon, the missions principle scientist.

‘Messenger’ will reach Mercury after a seven-year sojourn through the solar system that will take it 15 times around the sun, making near passes of Earth once, Venus twice, and Mercury itself three times.

Each planetary pass will act as a gravitational tug to slow Messenger’s speed so that it can eventually slip into Mercury’s orbit for a year-long study. The only other up-close look planetologists have had of Mercury came in the mid-1970s when NASA’s ‘Mariner 10’ spacecraft made three fly-bys, photographing about 45 per cent of the planet and discovering that it had a strong magnetic field, an indication, scientists say, that Mercury is about two-thirds iron.

Developed by the Applied Physics Laboratory at the John’s Hopkins University of Baltimore, Messenger will spend at least a year in orbit around Mercury looking for similarities with Venus, the Earth and Mars.