If a stream of grains is in orbit about a central body such as the sun, a vehicle could accelerate along the stream using magnetic propulsion. After reaching a high velocity, i.e., a significant fraction of the speed of light, the vehicle could reach the end of the stream and enter free space. Although such a system would require investments in space beyond present levels, it could be realized without major technological advances. One of the requirements of a propulsion system using an orbiting grain stream would be maintenance of the grain-stream shape. Vehicles traveling along the stream with low relative velocities could be used. Some of the problems of maintaining the stream are discussed, as well as maintenance-vehicle requirements.