The boosters can improve the efficiency of launch-vehicle usage because they can be employed in various combinations and configurations to meet the thrust needs of heavier payloads, thus eliminating the need to develop new, specialized main engines or launch vehicles. When the top is spinning, a force applied to the side is needed to make the gyro tilt. This principle is used to control the attitude of a space vehicle in flight. When the attitude of the spacecraft changes, the reactions of the gyros are measured electrically and the information transmitted to an operator or monitoring computer. A laser gyro uses the characteristics of laser light, rather than the innate stability of the spinning top of a mechanical gyro, to detect changes in spacecraft attitude.
Laser light is projected along the sides of a triangle.
When the spacecraft rotates to the right the distance the clockwise laser beam has to run is increased while the distance covered by the counter-clockwise laser beam is decreased. When the two beams are compared after one circuit of the triangle, the direction and degree of the spacecraft's rotation can be calculated. Like conventional gyros, laser gyros are installed to monitor the three axes of movement of the spacecraft so that its attitude can be checked at any moment. A laser gyro has several advantages over a mechanical gyro system. The overall unit can be made smaller, lighter, and more sensitive.