You have to wait two years for the trajectory, for the plans to come back around. So you have a window to come home. So you do have to stay awhile. But the beautiful thing is, if you can go someplace and gas up again, fill up your tank without having to bring all the gas with you, that's huge, right? You can carry so much more that way with the carbon dioxide that's in the martian atmosphere and the water that's in the ice that's on the surface of Mars, you can have a reaction, a process that allows you to create, to take those two things and make liquid methane, and you could have a tank of that ready to go. And all done robotically, you could get the telemetry back saying, we got the gas, and then you go now, how.