Phobos (moon) energy due to wind blowing dust off of its solar panels, took several short-exposure photographs of the night sky from the surface of Mars. Phobos and Deimos are both clearly visible in the photograph. The Soviet Union undertook the Phobos program with two probes, both launched successfully in July 1988. "Phobos 1" was accidentally shut down by an erroneous command from ground control issued in September 1988 and lost while the craft was still en route. "Phobos 2" arrived at the Mars system in January 1989 and, after transmitting a small amount of data and imagery but shortly before beginning
Stability of the Solar System essentially the distance from sun to earth). These are now known as the Kirkwood gaps. Some asteroids were later discovered to orbit in these gaps, but their orbits are unstable and they will eventually break out of the resonance due to close encounters with a major planet. Another common form of resonance in the Solar System is spin–orbit resonance, where the period of spin (the time it takes the planet or moon to rotate once about its axis) has a simple numerical relationship with its orbital period. An example is our own Moon, which is in a 1:1 spin–orbit resonance