Prepared for Mercury 2nd Flyby by MESSENGER
10 months ago, MESSENGER, a spacecraft designed to study Mercury, made its first flyby of the innermost planet. On this coming Monday, October 6, MESSENGER is going to make its second flyby, passing a mere 200 km above its surface.
The primary purpose of flyby is to use Mercury for a gravity assist to tighten the spacecraft’s orbit and to keep it on track so that it can enter into orbit around Mercury in 2011, becoming the first spacecraft ever to orbit Mercury.
Gravity assist is important because it can greatly reduce the fuel load requirement of MESSENGER by using the gravitational attraction of planets to change and shrink its orbit about the Sun. The more massive the planet and the closer the spacecraft passes above the planet, the greater the change in the spacecraft’s orbit.
Since the launch of MESSENGER from Earth on August 2004, it has already flown past Earth once, Venus twice and Mercury once. This upcoming flyby and another last pass of Mercury in September 2009 will use Mercury’s gravity to brake and guide the probe progressively closer to the planet, so that at the 4th Mercury encounter in March 2011, Mercury can “capture” MESSENGER into orbit around the planet.
MESSENGER mission timeline featuring major trajectory adjustments.
Although gravity assist is the main priority, we, of course, will not miss the chance to snap some beautiful pictures and make some measurements.
During the first flyby in January, MESSENGER captured images of about 20% of Mercury’s surface not previously seen by any spacecraft, revealing new and unexpected features. During this second flyby, MESSENGER plans to reveal another 30% of the surface that has never been seen before. It will show us a completely new surface, opposite from the side of the planet we saw during the first flyby.
Additional to revealing new surface features, other instruments onboard the spacecraft will also be busy taking measurements, such as the Mercury Laser Altimeter (MLA), the Visible-Infrared Spectrograph (VIRS) on the Mercury Atmospheric and Surface Composition Spectrometer (MASCS), the X-Ray Spectrometer, and the Gamma-Ray and Neutron Spectrometer.
The second flyby is expected to yield more surprises. Stay tuned for more updates and more images of our smallest planet!
Source: MESSENGER Mission News
My Dark Sky 
[…] this is Mercury, taken by MESSENGER during its second flyby on Monday. The bright stripes that make it look like a watermelon is known as rays. When something […]
Images from Mercury 2nd Flyby « My Dark Sky said this on October 8, 2008 at 2:29 pm |