Wednesday, January 1, 2014

Exactly how close?

In my last post, I commented on the Chinese lunar lander and the picture of it that the Lunar Reconnaissance Orbiter aquired.  Both missions are impressive technological achievements, and either landing on Luna or conducting operations in close lunar orbit are risky endeavours.

The European Mars Express orbiter just did another high risk maneuver in space, making a flyby of Phobos within 28 miles (roughly the distance between the closest points of the Washington Beltway and Baltimore Beltway).  That too is impressive.  Now, these satellite controllers all know exactly how to command their satellites to make this maneuvers routinely (Cassini around Saturn has does several close approaches to different moons), but it's still pretty remarkable that they can come this close.

The reason they did it was to get as accurate an estimate as possible of the density of Phobos by monitoring changes in a continuously transmitted radio signal. 

Chalk up another achievement for the techno-science-geeks.

Because they were transmitting a continuous signal, they didn't get pictures on this pass.  Below is a shot from a different flyby.

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