4 ms·
Assuming they'll deliver you onto a Mars transfer orbit, you need ~2 km/s for the Mars capture maneuver. Assuming you have an engine with ~300s Isp, you need a
by schwarrrtz 10y ago
Assuming they'll deliver you onto a Mars transfer orbit, you need ~2 km/s for the Mars capture maneuver. Assuming you have an engine with ~300s Isp, you need a mass fraction of exp(-2/3) ~ 0.5. So you need your payload to be about 50% fuel by mass.
Also, this doesn't account for any aerobraking, which should save you some fuel.
http://space.stackexchange.com/questions/12660/delta-v-to-low-mars-orbit http://space.stackexchange.com/questions/12660/delta-v-to-lo...
- the8472 10y ago> Assuming you have an engine with ~300s Isp, you need a mass fraction of exp(-2/3) ~ 0.5. So would taking a longer earth-mars route that allowed the use of some more efficient drive (e.g. ion engine) improve the amount of payload that could be delivered?
- schwarrrtz 10y agoYes, 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