Out of This World
There is growing demand for smaller, more affordable satellites that can be deployed quickly. Honeybee Robotics, a spacecraft technology company in New York City, says it has developed a more efficient way to steer them once they are in orbit. Most small satellites contain reaction wheels that speed up to increase torque and aim the spacecraft. Honeybee's steering devices, which it calls nano control moment gyroscopes, can be set to maintain a constant speed, creating gyroscopic torque by tilting a spinning steel rotor. As a result, the devices are more energy efficient. The CMGs, which are about 2 inches long and 2 inches wide, are miniature versions of those used in large satellites. Honeybee hopes to begin selling them to spacecraft manufacturers by 2012.
The CMG at above right is shown at a 50 percent magnification. Its tiny steel rotor and two motors are encased in a steel gimbal frame.
Honeybee's CMGs are designed for use in satellites that weigh from 11 pounds to 220 pounds. These smaller satellites can be used for conventional purposes or deployed quickly to monitor natural disasters, say, or track fast-moving asteroids.