> that is, we have enough fuel to spare that we can make correction-burns if necessary during the trip to Mars. Stage 2 of the Falcon would not be used for lon

> that is, we have enough fuel to spare that we can make correction-burns if necessary during the trip to Mars. Stage 2 of the Falcon would not be used for long flights. This was the longest it ever coasted (6 hours). Any longer, and you run into all sorts of limitations: running out of batteries, RP-1 freezing, and LOX boiling off. For longer trips, stage 2 would separate after the earth escape burn and the craft's own propulsion system would take over.