11.   The fear was that the Soyuz could slam into the shuttle or spray it with engine exhaust.

12.   The fear is that the Soyuz could slam into the shuttle or spray it with engine exhaust.

13.   The system would complement existing catalytic converters, which remove most of the pollutants from engine exhaust.

14.   After stowing the satellite, the astronauts turned their attention to a study of engine exhaust and took video pictures of Hurricane Marilyn.