In March, 1989, the Russian probe PHOBOS II mysteriously stopped communicating, and has never been heard from since. In the last few images sent, the cigar-shaped shadow below was sent. Click here for an article discussing some of the speculation considering it's disappearance, and other probe failures.
Now, from the Mars Orbital Camera, comes the following two pictures of strange tower like structures, and the long shadows they cast......
Could these be some sort of defensive weapons, that activated when the PHOBOS II and other probes came too close? If so, are they designed to keep others away, or from leaving?