大 Question Is there an alternative to using propellant? Single spacecraft Yes. If an external field exists to conserve momentum Otherwise. not that we know of Multiple spacecraft Yes, again if an external field exists OR, if each spacecraft produces a field that the others can react against Problem: Momentum conservation prohibits control of the motion of the center of mass of the cluster, since only internal forces are present DIl EMFF Final review ug.29,2003DII EMFF Final Review Aug. 29, 2003 Question I: Question I: • Is there an alternative to using propellant? • Single spacecraft: – Yes, If an external field exists to conserve momentum – Otherwise, not that we know of… • Multiple spacecraft – Yes, again if an external field exists – OR, if each spacecraft produces a field that the others can react against – Problem: Momentum conservation prohibits control of the motion of the center of mass of the cluster, since only internal forces are present