31 December 2017

There's a Hell of a Good World Next Door

Image credit: U.S. Air Force
I am fond of Mars - honestly, who isn't? It looks a little like some parts of Arizona, the southwest U.S. state where I live, so at first glance it seems cozily familiar. The cultural history of Mars is rich: it has been a favorite science-fiction setting for more than a century.

Most exciting to me, Mars might yet prove to be a home to life. We'll likely determine whether Mars lives by exploring the planet's delightfully complex geology. It seems probable, given how inhospitable is Mars's surface, that, if there is life on Mars, then it will be life in Mars. After all, much of Earth's biomass lives deep within its crust, happily metabolizing rocks and hot water. A few kilometers down, Mars and Earth might provide virtually identical habitats for life.

Mars exerts a powerful pull on our emotions. That being said, however, one has to exercise caution when emotions are part of the mix (as they always are). The thought of humans on Mars is exhilarating. Should humans, however, actually set booted foot on Mars?

I think the answer to that question must be yes - eventually. Humans should travel to every place they can. As we gain experience, improve our technology, develop new spaceflight concepts, and mull over data received from our robotic spacecraft, we become more capable. As we become more capable, we increase the probability that we can achieve success.

By "success," I mean several things. There's the obvious one: we increase the likelihood that humans will survive the Mars trip without short-term or long-term injury and be able to perform meaningful exploration. We also increase the likelihood that we will not clumsily interfere with the study of any native living things by accidentally introducing terrestrial biological contamination.

It would be really helpful if we had a place nearby where we could prepare ourselves for journeys throughout the Solar System. A good-sized world with a range of exotic alien environments and a complex geology. A world from which we might return rapidly if we got ourselves in over our heads. Bonus points for a world we can reach cheaply, using technologies we have at hand, and from which we can extract resources that could facilitate our journeys to more distant worlds.

Such a world exists. It bears boot prints nearly half a century old. Using technology shockingly primitive by modern standards, 12 humans walked, worked, and drove there. When they needed advice and assistance, they spoke with a support team back on Earth with a one-way radio time-delay of only 1.25 seconds. One spacecraft suffered a crippling oxygen tank explosion, but Earth was close enough that its crew was able to return home safely.

I've expressed my views concerning this nearby world before on this blog. I've called it a part of Earth. Together with Earth, it forms a binary world unique in the inner Solar System. Mercury and Venus have no moons; Mars has two, but they more closely resemble middling-sized asteroids than they do planets. Earth, however, has as its near neighbor the planet-size Moon, a world which, were it a continent, would rank after only Asia in surface area. It is the fifth-largest moon in the Solar System; only Ganymede, Titan, Callisto, and Io, all moons of outer Solar System gas giant planets, are larger.

We have barely explored our Moon. Automated and piloted orbiters have surveyed its entire surface off and on over the past half-century, but no functioning spacecraft has landed on the Farside, the hemisphere of the Moon we cannot see. Nor has any spacecraft soft-landed near its poles, where ice hides in permanently shadowed craters at temperatures near those the New Horizons spacecraft measured at Pluto.

The ice at the lunar poles might supply life support consumables and rocket propellants for at least tens of thousands of years. By virtue of its low gravity - just half that of Mars and one-sixth that of Earth - and its lack of an atmosphere, the Moon could become an economical water supplier for an Earth-Moon infrastructure that might include habitats, spacecraft service stations, powerful observatories, lasers for boosting light sails, human-tended factories, and other facilities. Many of these facilities could be built at least in part from lunar titanium, aluminum, and glass. By the time the Earth-Moon infrastructure attains that level of sophistication, propellants needed for fast and frequent piloted journeys to Mars will amount to an incidental fraction of the total produced on the Moon.

Developing the Moon also gives us time to try to determine, using robots, whether life exists on Mars. It buys us time to decide what Mars life - and, indeed, life of other worlds - should mean for us and our posterity. Microbial life on or in Mars might not be a dead end; it might instead be biding its time. After all, for nearly all of its history, life on Earth was strictly microbial.

Gaining experience in the Earth-moon system opens up many new opportunities beyond Mars. If we determine that long-term habitation of Mars is undesirable, then the lessons we learn and capabilities we acquire by developing the Moon and cislunar space could be readily applied to worlds throughout the Solar System. Consider this: Earth and Moon resemble more worlds in the Solar System than does Mars. The Moon resembles any number of vacuum worlds with significant surface gravity (Mercury, Ganymede, Iapetus, Miranda, Pluto), while Earth shares traits with Venus and Titan. Only Mars combines significant gravity with just enough atmosphere to raise dust storms.

If Mars pulls on our emotions, then it is probably not too bold to say - without any hint of superiority - that the Moon pulls on our minds. Of course, people who value the Moon have an emotional stake in it. It seems different to me, however, than the exuberance many feel toward Mars. I suspect that, if you have read this far, then you might see a difference, too.

Image credit: NASA

The post title is a play on the last line of e. e. cummings' free-verse sonnet "pity this busy monster, manunkind," published in 1944. That line reads - "listen: there's a hell of a good universe next door; let's go"

More Information

The Eighth Continent

Harold Urey and the Moon (1961)

"A Continuing Aspect of Human Endeavor": Bellcomm's January 1968 Lunar Exploration Program

Rocket Belts and Rocket Chairs: Lunar Flying Units

Apollo's End: NASA Cancels Apollo 15 & Apollo 19 to Save Station/Shuttle (1970)


  1. A good post to start the new year. Humanity really needs to think this through & proceed in a rational fashion.
    Happy New Year.

  2. Kerrin:

    Happy New Year! Rationality isn't a strong suit for many humans, alas. I am as bad as anyone else in that respect. We are faced with many dangers here on Earth, mostly human-caused, and yet here I am, talking about keeping possible microbial life beneath Mars's surface safe from accidental contamination.


  3. A merry christmas and happy new year

    1. Thank you, Michel - and best wishes to you for 2018!


  4. Apparently the concentration of volatiles needn't be very great to enable a lunar ISRU production scenario. Some recent studies of lunar ISRU mining have a baseline of just 2 wt% water ice. That's fairly slim pickings, but some think it's a workable percentage.

    And looking to the other end of the Earth/Mars route, we see that Deimos has a very low density of 1.5 g/cm3, which might indicate far more abundant volatiles, conceivably 50 wt%, though of course in situ proof is needed. But the evidence at hand suggests Deimos could be much easier to mine: an efficient supply of propellant for Mars launches, and, with depot flights, conceivably for burns from LEO as well.

    We explored the numbers for this particular possibility with our Omaha Trail proposal, at lakematthew.com. It would be interesting to see how a lunar ISRU plant might be expected to complement.

  5. on Lunar ISRU
    it depends what is Hydrogene deposit on moon poles are made of (we need a rover up there)
    if it's water ice is will be easy to process into Lox-Hydrogene.
    but if stuff is hydride or worst Transition metal hydride
    you need allot energy to process it.

    And if you have put allot energy into it
    we just stay at equator and ISRU on Lox out of Moon soil and import needed Hydrogene or Methan from Earth.
    and export the byproducts like Steel, Titan, Aluminum, Glas and Rare Earth Elements*
    use Lox and Dirt as rocket fuel, ISP is lousy but it get you off moon to earth orbit

    * Rare Earth Elements is needed for production of Smartphones, Computers and battery for Electric cars
    and like name say is rare on Earth, but most of moon soil is made of that stuff !

    1. Michel:

      There are ~80 processes for mining oxygen from lunar dirt, as I understand it. I don't understand all (or even most) of them. In this post, I focused on water ice at the lunar poles because I wanted to play up the many different kinds of environments that exist on the moon. It's a complicated place, yet I find many behaving as if the six Apollo sites told us everything we could ever know about it. We've barely begun to explore it.

      That being said, water ice at the poles is a little like life on Mars. We aren't sure about the existence of either. We need to take the time to learn about both so we can make intelligent decisions about our future in space. Are we going to behave like conquistadors and barge in on every potential living world? I hope not. Are we going to assume ice when it's still not certain? Again, I hope not.

      BTW, would the "Mountain of Eternal Light" (really part of the rim of Malapert crater) potentially serve to provide enough energy to make processing more difficult forms of oxygen-hydrogen-rich materials worthwhile?



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