1. 2Griffin, B. et al. "A comparison of transportation systems for human missions to Mars", AIAA 2004-3834, 40thAIAA/ASME/SAE/ASEE JointPropulsionConferenceand Exhibit, 11-14july2004,FortLauderdale,Florida
2. 8Koppel, C. "High Power Electric Propulsion System for NEP", 1stsymposium on potentially disruptive technologies and theirimpactin spaceprograms,Marseille, France,July4-6,2005