NASA’s Messenger Enters Mercury Orbit!

"It was right on the money," said Eric Finnegan, chief engineer of Messenger, to BBC. His whole team was very elated and why they won’t be? Messenger, a spacecraft by NASA has become the first craft ever to enter Mercury orbit, the innermost planet of our solar system. This is for the first time ever when a satellite has achieved this milestone. It was launched more than 6 years ago.

Messenger was launched from earth in August 2004 and since then has travelled a distance of 7.9 billion kilometers (about 4.9 billion miles), making its way to the mercury through some extreme conditions! It is now some 46 million Km from the Sun and about 155 million Km away from the earth. Before Messenger, NASA had implemented the Mariner program for measuring various characteristics of Mercury.

The Messenger has seven instruments including the Mercury Dual Imaging System (MDIS), the Energetic Particle and Plasma Spectrometer (EPPS) mounted on it. It also has to carry a huge shield that protects it from the intense radiations from the Sun which may even melt the satellite! Also the instruments which face the planet need to be protected from the radiations coming back off the surface of Mercury.

As per the strategy devised by the NASA engineers and scientists, the Messenger will collect the data with its seven instruments when it is about 200 Km away from the planet’s surface and will send it back to earth when it is cooling off at about 15,000 Km away from the surface of Mercury. Messenger is scheduled to stay in the orbit for one year in which it will fly around Mercury for 730 times.

Mercury is supposed to be a place with extra-ordinary extremes! The highest temperature on the planet reaches about 600C and the lowest being negative at the poles which never receive the sunlight and may even have water ice. The planet is very dense and is supposed to have at least 2/3^rd of its body made up of Iron-metal composition.

Mercury takes just about 88 days to complete one revolution around the Sun. Thus when compared with Earth’s 365 days, Mercury’s one year is just the 1/4^th of the Earth year. On the other hand, Mercury rotates very slowly. It takes about 176 days for one rotation which is about 2 Mercury years! (Half Earth year)

The journey now on will surely be an exciting one. Mercury’s close study will reveal many new things and will surely help in understanding the universe better! Many more space agencies around the world are set to send their satellites to Mercury this decade and Messenger will be a very good lead for them!