[roywiggins]

Mars is close, it's not got hellish Venusian weather, it's got a clear atmosphere that's easy to look through, you can roll rovers around on the surface pretty easily. If you want to generalize your ideas about what geology does, then Mars is a nice place to observe that isn't Earth. And if we are very lucky, we will be able to generalize our ideas about life by finding some there. It also has interesting chemistry, weather, etc. It's like Earth, but different. You can test theories about how planets form against it.

It's easier to image the entirety of Mars than it is to image, say, the Pacific. It's easier to send a rover to Mars that will survive for years on Mars than it would be to send one to the depths of the Pacific, too.

[forapurpose]

> hellish Venusian weather

In Mars' wonderful weather, pressure is so low, at 0.006 atm, that IIRC water boils in the ambient environment, and gravity is 0.376 G.

Around 50 km above Venus, pressure is about equal to Earth, gravity is equal to Earth, and temperatures are a very friendly (relative to all locations in the universe outside Earth) 30-80 deg C. (Also, breathable air is lighter than Venusian atmosphere, so a floating base is a bit easier; and Venus is closer to Earth than Mars.)

There are drawbacks to living in a Venusian airship, or so I'm told, but weather-wise it's pretty good.

[roywiggins]

Sure, there's engineering issues on Mars, but the longest-lasting device anyone's put on the surface of Venus lasted only a couple hours.

Neither are exactly prime vacation spots, but if you want a target for robotic exploration, Mars is so much easier.

[TeMPOraL]

GP has a good point, though. Venus is hostile on the surface, but higher up in the atmosphere the conditions are much nicer, and you could hang dirigibles there. Not interesting if you want to study geology, but very interesting for climate science, and I hear that you could extract enough useful stuff from lower parts of the atmosphere that it could actually be a viable colony spot.