HELI-90/120/140 refers to a helicopter, with the servos orientated at 90 degrees (2 servos, generally beginner helicopters with forward, back, right, and left movement on the cyclic stick), 120 degrees (3 servos- generally for more advanced helicopters that have collective pitch controls on the rotor blades (yes, this means inverted flight too)), ...
canyon. n. 1. (Physical Geography) a gorge or ravine, esp in North America, usually formed by the down-cutting of a river in a dry area where there is insufficient rainfall to erode the sides of the valley.
Covering nearly a fifth the circumference of Mars, the canyon system Valles Marineris reigns as the largest canyon system on the red planet. Dwarfing its Earthly counterpart, the Grand Canyon, the Martian feature is one of the larger canyons in the solar system. Characteristics. Valles Marineris is a system of canyons that spans 2,500 miles (4,000 kilometers). At some points, the canyon is 125 miles (200 km) wide. Regions can reach depths of 6 miles (10 km). If the system were located on Earth, it would stretch across the United States, from Los Angeles to the Atlantic coast.