Spacecraft Reentry FAQ:

Can we control where debris will land?

In some cases, we can control the location of the debris footprint by performing a deorbit maneuver. If the satellite or rocket stage has propulsive capability, it can be commanded to execute one burn or a series of burns designed to lower the orbit perigee so that the object will reenter at a specific location. This same type of maneuver is used to deorbit the space shuttle orbiter at the end of a mission. Very few satellites and rocket stages have sufficient propulsion capability to perform a controlled deorbit.

For larger objects, which pose a hazard to people and property on the ground, a controlled deorbit is most desirable since this technique assures that the debris impacts in the ocean. A good example is NASA's recent deorbit of the 14,000-kg Compton Gamma Ray Observatory (CGRO) into the south Pacific Ocean. More than 35 percent of CGRO's mass was expected to survive reentry and the falling debris would be a hazard to humans if it fell in the wrong place. After the failure of one of its three gyroscopes in December 1999, the decision was made to deorbit CGRO in a controlled manner before its remaining gyroscopes could fail. CGRO was safely deorbited in the Pacific Ocean on June 4, 2000 via four thruster burns.

Further questions? Contact us at cords@aero.org .