atmosphereCurve { key = 0 330 key = 1 280 } Change key =0 to a higher number. That represents the ISP in vacuum. For example, { key = 0 830 key = 1 280 } Would have similar consumption to the nuclear engine.
To the munar surface and back! I almost tried for the runway, but had already descended to low by the time I realized it was a possibility. http://imgur.com/a/ZQlYD#0