Yes, definitely. If you had an engine with 3000s Isp, which according to Wikipedia wouldn't be unreasonable for an ion thruster, then your mass fraction would b

Yes, definitely. If you had an engine with 3000s Isp, which according to Wikipedia wouldn't be unreasonable for an ion thruster, then your mass fraction would be about exp(-2/30) ~ 0.94. So you'd only need 6% of your payload for fuel in that case. https://en.wikipedia.org/wiki/Specific_impulse#Examples https://en.wikipedia.org/wiki/Specific_impulse#Examples