Why Mercury could have a manned base
It has a magnetosphere that is strong enough to block the solar wind. That's a big deal because even Mars doesn't have that. I've wondered for a long time if there might be a small area somewhere near the rim of that permanently shaded crater on the south pole where there might be permanently moderate temperatures? Even if not, that huge crater would be be an ideal place for a base since there are likely ice deposits. Plenty of iron to mine to build a solid underground base.