starting March 18th, 2011
In an exciting bit of space news, The NASA MESSENGER spacecraft is set to enter orbit around Mercury on March 18th of 2011, marking the first time in history a man made object will be placed in orbit around the planet closest to our sun. MESSENGER will orbit Mercury for a full year, recording numerous images and instrumental readings and transmitting back a wealth of data to help scientists better understand the closest planet to our sun.
MESSENGER was launched in 2004 from Cape Canaveral aboard a Boeing Delta II rocket and was slingshot around the earth in 2005 to accelerate it into the inner solar system. It flew by Mercury in January of 2008 on its way to aligning itself properly for entry into Mercury’s planetary orbit, at which point it sent back some amazing images of the planet and got scientists even more excited about the coming orbiting mission.
Mercury is a mysterious planet that has baffled scientists. Like the earth, it has a global magnetic field and like the moon, its surface is heavily cratered but it shows signs of comparatively recent geologic activity. It is also home to the giant Caltorsis crater, one of the largest craters in the solar system, which scientists think was created from an impact. Yet instead of being light on the edges and dark in the middle like the Moon’s craters which have dark, lava-filled interiors, Mercury’s craters are dark on the edges and are filled with very light plains. Scientists still don’t understand why this is so, but hope to learn this and much more during the spacecraft’s orbital visit. Another thing they hope to understand is why Mercury is so metal rich and much denser than its sister planets Venus, Earth and Mars.
Mercury is a very hot place: the average surface temperature is about 840 degrees Fahrenheit, and the sun is 11 times brighter there than it is here on earth. The MESSENGER spacecraft is equipped with a specially designed ceramic cloth shield that it will “hide behind” during its entire mission, keeping the temperature around the spacecraft a comfortable room temperature.
Messenger’s orbit around Mercury will be elliptical. The closest it will come to the planet will be a mere 124 miles. The farthest it will go out is 9,420 miles. The spacecraft will have to slow its speed by half a mile a second in order to enter orbit around Mercury. It will use almost 1/3rd of its fuel in order to do so by firing its main thruster, which will point almost directly to the forward direction of the spacecraft and act as a ‘thrust brake’.
Exploration and research of the historic MESSENGER voyage may be a very attractiveScience Fair Project for students. The science behind the different MESSENGER missions planned for its yearlong Mercury visit may also help students conceptualize and design their own compelling Science Fair experiments.