Idk where i picked this up, but there is one other plausible colony destination for humans: Venus. After a few trips on the net, i've come to the "Aerostat on Venus" side instead of a colony on mars. I'll mention some of the reasons i've picked up as to why: 1. Tons of CO2, we can use that. 2. Earth-like gravity and pressure at 50km: So deltaP-catalysed explosions are not at risk there on venus. 3. Radiation shielding by Venus' atmosphere, but i read somewhere that few meters beneath the Mars surface would also give a similar shielding. 4. The atmosphere at Venus at 50km altitude is more hospitable than that of Surface Mars. I've tried to look for data such as density of the Venus atmosphere at that altitude, climate of venus etc. but it seems like there's not much data. What are the prime reasons for opting Mars instead of Venus? Hype and lack of data are not viable reasons, and shouldn't be. I'm also unable to find proper side by side comparisons of the two possibilities.