I've been prattling on about (synthetic) Martian spiders for a few weeks now¹. It's an interesting topic but I'm beginning to wonder if anyone has caught on to what we're _really_ talking about? All these discussions about the things our hypothetical Martian spiders would need to deal with - the extreme cold, the lack of oxygen, the radiation and so on - What's the common factor?

The common factor is the planet Mars, of course. We've been studying Mars. Well, "studying" might be a bit optimistic. But we've learned a few things about it, haven't we?

It's a truism that if you want to send someone or something to live in a place, you have to know what it's like. You make sure they have their shots and the right clothes. For example, you don't send people to invade Russia without good warm uniforms². And you don't send people to the Bahamas with wool shirts and jackets and without so much as a drop of salt. Not if you want them to survive anyway.

Just so, if you want to settle on Mars, you had better figure out what you're going to need. I don't personally expect to ever get to Mars but that's just me. Somebody is going to go. This century, if not sooner.

And you know what they're going to have to face?

Before we get to that, it's time for me to complain about technology. Because this is a tech column, see? And my clothes washer is broken. We've had it a little over 3 years. It broke once before when it was still under warranty. It took weeks to get the circuit board that needed to be replaced. I think it's probably going to need exactly the same part again. Only this time, it's not under warranty, meaning it's going to cost a fortune. After waiting some unspecified number of weeks for it to arrive.

And I'm still wondering why a clothes washer needs those fancy and expensive electronics, anyway.

I can see you you're shaking your head right now. Partly it’s in sympathy but mostly because you don't see the connection between Mars and a broken clothes washer. Well, if you're trying to set up shop on Mars, and your clothes washer or your water purifier or your life support computer breaks down, the amount of time it takes to ship a part from Earth is going to be incredible³!

Mars is about 1.5 Astronomical Units (AU) from the Sun. Aka about 142 million miles out. Coincidentally, Earth is exactly 1 AU from the Sun. But that's a little misleading since neither planet orbits in an exact circle. Both go in ellipses, meaning they are closer to the Sun at one end of the orbit than they are at the other.

Earth and Mars take different amounts of time to go around their orbits, too. For the Earth it's (surprise!) 1 year. For Mars it's about 687 days. Earth days, I mean. Martian days are slightly longer than Earth days. So, let me do the math here (or let the calculator do it. But I'll punch the buttons.). 687 days divided by 1 year (365 days) equals 1.88 or so Earth years for every 1 Mars year. For the mathematically impaired, that's almost 2 for every 1.

You know what that means? It means that at any given time Mars and Earth might be kind of close together, roughly 50 million miles apart. Or they might be on completely opposite sides of the Sun. Add a couple hundred million miles or so. That means that your hypothetical washing machine component will have to go all the way around the Sun to get from here to there. Except that it takes months to get from here to there, so by the time you've covered all those millions of miles, Mars is someplace else. You have to aim where it's going to be, not where it is.

There was a recent article on Phys.org that pointed out that travel time to Mars could be cut in half if we just used nuclear rockets instead of chemical ones⁴. So, four months without clean clothes instead of 8? Great! What a relief!

I'm sure Elon Musk already has people working on nuclear rockets. There are some engineering issues to solve, like not knowing how to do it. But nothing too serious.

Anyway, back to Mars, so to speak. The distance and the time factor for getting spare parts is a big reason why I concluded that we should engineer living things to help us explore and terraform⁵ Mars. It doesn't have to be spiders. I just love the imagery. And the potential. Spiders have a lot more potential for dealing with hostile environments than fish or vultures or koala bears. Maybe not as much as cockroaches, though. But who wants to write a song or history book or even a scientific paper about making Martian cockroaches?

There are still important hurdles we haven't talked about. Mars's distance from the Sun and the shape of its orbit, combine with the planet's axial tilt (almost the same as Earth's) to give it some interesting weather. Yeah. In previous posts in this series I talked about how the atmosphere on Mars is too thin to breathe. And it is. But it's still an atmosphere. That means Mars has wind.

Therefore, Mars has storms. Giant dust storms. There's a huge amount of dust on Mars. That's pretty much what the surface is. Lots of rocks that have been worn down by the wind or by millions of years of heating up during the day and cooling off at night, until there's a fine layer of iron-oxide dust over everything⁶. The wind is slower than it is on Earth. It probably never even gets strong enough to be called a hurricane⁷ but every once in a while one of those dust storms will get big enough to cover the entire planet.

Let me repeat that.

Call me crazy but I would LOVE to see one of those. From a ship outside the atmosphere. I'm not that crazy.

What a place, huh? Next time we'll talk about the most important thing if we want anything (including us) to live on Mars: Water.

Did you know that there are spiders that swim? Never mind! Come back in a few days and see what comes next, for the Spiders of Mars!

Here's that prompt: "A cartoonish scene of two large spiders relaxing on deck chairs, sunning themselves while being served colorful cocktails by a robot waiter. All of them look surprised as a massive sandstorm, full of swirling dust and wind, approaches the horizon. The sandstorm dominates the background with a dramatic, sweeping motion. The scene is set on Mars, with reddish sand, rocky terrain, and the sky dark with stars where the sandstorm hasn't covered it."

This one doesn't look much like the prompt but at least I convinced it to get rid of the mushroom cloud!