February 21, 2011

MESSENGER Probe Set To Enter Mercury Orbit In March

NASA's MESSENGER probe is about set a milestone for spacecraft as it becomes the first probe to orbit Mercury.

MESSENGER's team outlined details to scientists at a conference in Washington DC.

The spacecraft has already made three flybys of Mercury and is set to enter orbit around the rocky world on March 17.

NASA's Mariner 10 spacecraft made several passes of the planet in the 1970s and sent pictures back of what appeared to be an uninteresting planet compared with Venus, Mars and the Solar System's gas giants.

However, Dr. Nancy Chabot who is MESSENGER's instrument scientist said Mercury was "under-appreciated."

The planet is the closest to the Sun, but some scientists say that it could have ice at its poles.

The planet has a giant metal core unlike any of the other inner Solar System planets.  Planetary scientists began to think that understanding Mercury might be the key to understanding how all the inner rocky planets formed.

Chabot told BBC:  "What you can learn when you are in orbit is so different from when you are just flying past by gathering data as you go. This is really going to revolutionize what we know about this planet."

MESSENGER will be the first spacecraft to study Mercury's geology in detail.  Scientists will be interested learning more about the planet's giant core.

Three theories as to how the planet came to have such an inner structure include:  It was created that way; it used to be much larger and a giant impact ripped off much of the rocky crust; or that Mercury was once much larger but an early solar event vaporized its surface.

The MESSENGER mission should help determine which of these theories is correct.


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