That day-night cycle isn't to be downplayed. A greenhouse on Mars is a totally viable approach to feeding the locals - you just need to keep the air in, and ai

That day-night cycle isn't to be downplayed. A greenhouse on Mars is a totally viable approach to feeding the locals - you just need to keep the air in, and air processing is a helpful second use. On the Moon all that stuff must be done in a more energy intensive, techy way.