The Case for Mars

Vote for me on Love To LeadThis is a response to the ques­tion Will the human race ever pop­u­late another planet? pos­ted on Toshiba’s Love to Lead site. Toshiba set a ques­tion and then blog­gers answer it, with links back to the Toshiba site in the hope of win­ning a laptop. You can also add a but­ton like the one on the right like I have, because I’m not proud. It looks like an inter­est­ing com­pet­i­tion, but more import­antly it’s an inter­est­ing ques­tion. It’s also an excuse to talk about Robert Zubrin’s thought pro­vok­ing book The Case for Mars.

Populating another planet really depends on two factors. There has to be the abil­ity and the will to settle another planet. If we lack either then it will not hap­pen. in par­tic­u­lar, the crunch point is the abil­ity. Is it phys­ic­ally pos­sible? If it’s not then no amount of wish­ing is going to make it hap­pen. What are the chal­lenges we need to over­come get­ting to, and set­tling on, Mars? Shortly after read­ing Oliver Morton’s excel­lent Mapping Mars, I read Robert Zubrin’s The Case for Mars, as it was men­tioned so often by Morton. If you want an over­view of the prob­lems in inter­plan­et­ary col­on­isa­tion this is an excel­lent intro­duc­tion. Even if you don’t agree with the con­clu­sions, the explan­a­tion of the prob­lems he tackles is usu­ally eye-opening. For instance, first of all you’ve got to get there.

Getting to Mars

There are a few prob­lems in get­ting to Mars. The method that uses the least energy is a Hohmann orbit. This is an ellipse where the low­est point in the orbit meets Earth, and the highest point is at Martian orbit on the other side of the Sun. If you fly this orbit then you’re com­mit­ted to around nine months of travel. This means nine months of sup­plies and power. It also means nine months of weight­less­ness and nine months of being exposed to cos­mic radi­ation. These are both ser­i­ous prob­lems because it could mean that when you arrive in orbit around Mars, you’re not going to be in a fit state to land. The solu­tion to weight­less­ness that Zubrin pro­poses is elegant.

If you’ve seen 2001 then you’ll have seen Kubrick’s rotat­ing space sta­tion. This, he thought, would be a neces­sity. The sta­tion gen­er­ated grav­ity by cent­ri­fu­gal force. If you sit in a rotat­ing space sta­tion you’ll feel as if you’re pushed out from the centre. Zubrin pro­poses that any space­ship sent to Mars should rotate around a counter-weight to sim­u­late grav­ity. This gives your muscles some­thing to push against, and so they don’t waste away dur­ing the flight. The radi­ation is harder to avoid.

Radiation is one of the reas­ons why some people think the Moon land­ings were a hoax. The Earth is sur­roun­ded by the Van Allen belts, regions of strong radi­ation. The radi­ation is particles spewed out by the Sun and con­cen­trated by the Earth’s mag­netic field. If the Apollo astro­nauts had dawdled in the Van Allen belts then they would have all died of can­cer. The radi­ation between Earth and Mars isn’t so intense, but the length of the trip will mean that there might be a fatal expos­ure. Zubrin spends six pages tack­ling this prob­lem. It is real and he cal­cu­lates the dose will be around 50 rem on a two and a half year mis­sion to Mars. In real­istic terms this means that the chance of you get­ting devel­op­ing can­cer dur­ing the thirty years after you get back to Earth from a short Mars mis­sion will be 1%. Travelling to or liv­ing on Mars will be a risk, but sit­ting in a rocket fuelled with liquid hydro­gen is risk. Some people would be will­ing to take it.

Using chem­ical rock­ets to get to and from Mars is almost feas­ible with cur­rent tech­no­logy. It’s well within reach of a prop­erly fun­ded pro­gramme. But set­tle­ment is dif­fer­ent. Once you’re there what will you live off?

Settling Mars

Energy is going to a major prob­lem for any set­tle­ment. Oil and gas require bio­lo­gical depos­its, and they haven’t been found on Mars yet. Solar pan­els have proven amaz­ingly effi­cient for the Mars rovers Spirit and Opportunity. Nasa were expect­ing a large reduc­tion in the power avail­able to their rovers due to dust accul­mu­lat­ing on them. Instead what they’ve found is that particles in the Martian wind might be scour­ing the solar pan­els clean. Despite this Zubrin thinks he’s spot­ted a bet­ter source of energy, geo­thermal energy.

Mars is home to the Solar System’s largest vol­cano, Olympus Mons. This is huge. Staggeringly huge. It’s so massive that if you were stand­ing on Olympus Mons then you wouldn’t be able to see it, because it’s so large. That prob­ably doesn’t make sense. Surely the big­ger some­thing is, the easier it is to see? Imagine stand­ing in Kansas City and try­ing to see the whole of North America. This is the prob­lem you would have. Olympus Mons is a bulge on the sur­face of Mars, and must have been raised by a ter­rific amount of geo­lo­gical activ­ity. The best cur­rent guess is that this stopped mil­lions of years ago, but geo­lo­gic­ally speak­ing this is a short period of time. There are likely to be hot­spots where a col­on­ist could drill down to access still warm rock bur­ied deep beneath the sur­face. Pump water down one hole and it can emerge as steam to drive tur­bines from another, or else to heat the set­tle­ment. Hydrothermal power is a major energy source for Iceland, which is sat on a crack between North American and Eurasian tec­tonic plates. The first set­tlers, Zubrin notes, have the lux­ury of choos­ing exactly where to set up base, and this means that they can situ­ate them­selves dir­ectly over a suit­able hotspot.

What Zubrin didn’t know about when he was writ­ing his book is that there may well be liquid water close to the Martian sur­face. This was recently repor­ted by Nasa. With a source of energy and liquid water it’s pos­sible to pro­duce oxy­gen for breath­ing. Other prob­lems are then sol­uble if people are will­ing to make the effort. It won’t be a trivial effort though. Why on Earth would you want to go to Mars?

Zubrin puts for­ward two reas­ons. His worst is that America needs a fron­tier spirit. The Case for Mars is littered with cel­eb­ra­tions of how the West was won. Space explor­a­tion isn’t so much for all man­kind, but for the USA. This is a fea­ture which may grate if you’re from a coun­try where foot­ball is a game played with the feet. A bet­ter reason he puts for­ward is the chem­ical wealth of Mars. One thing Mars has which Earth doesn’t so much is Deuterium.

Deuterium is a form of Hydrogen. Usually Hydrogen is an atom with just one pro­ton and one elec­tron. Deuterium has one pro­ton, one elec­tron and also one neut­ron, mak­ing it twice as heavy per atom. It’s usable in nuc­lear react­ors today, and will be essen­tial if for fusion react­ors, if there is a will for clean nuc­lear energy and a reduc­tion in green­house gas emis­sions. On Earth around 160 parts per mil­lion of Hydrogen are Deuterium. On Mars Zubrin says it’s over eight hun­dred parts per mil­lion. The value of deu­terium per kilo­gramme is cur­rently less than gold, but not that much less. There may also be sources of rare-earth ele­ments. The lack of water on the sur­face of Mars means that wherever these ores were found, they’d be access­ible. Personally I sus­pect there may be some­thing more valu­able to be found on Mars that has yet to be found, due to the pres­ence of heat and water.

Life on Mars?

In 1996 Nasa issued a press release of a con­tro­ver­sial dis­cov­ery. It star­ted:

A NASA research team of sci­ent­ists at the Johnson Space Center (JSC), Houston, TX, and at Stanford University, Palo Alto, CA, has found evid­ence that strongly sug­gests prim­it­ive life may have exis­ted on Mars more than 3.6 bil­lion years ago.

The evid­ence was what appeared to be micro­fossils of bacteria-like organ­isms. This was rejec­ted by many as the bac­teria were too small. However, nanobac­teria may have now been found on Earth. Certainly there are thirty-four met­eor­ites known to have come from Mars on Earth. It is likely that explor­a­tion of Mars will find met­eor­ites from Earth on its sur­face. The two plan­ets have been exchan­ging small samples of mater­ial for mil­lions of years. Could bac­teria have hitched a lift on a met­eor­ite to travel from one planet to another?

The Apollo 12 mis­sion brought back samples from the Surveyor 3 probe. On the sur­face of the probe were still viable organ­isms of Streptococcus mitis. As Nasa says: “50–100 organ­isms sur­vived launch, space vacuum, 3 years of radi­ation expos­ure, deep-freeze at an aver­age tem­per­at­ure of only 20 degrees above abso­lute zero, and no nutri­ent, water or energy source.” Modelling sug­gests bac­teria could sur­vive the trip through space and land­ing on Mars. Could they live there?

A hot research topic at the moment is into extremo­philes. There’s no set defin­i­tion, but effect­ively it’s any organ­ism which sur­vives where you really, really wouldn’t expect it. They can be found in bur­ied lakes under­neath the Antarctic ice, in tem­per­at­ures in excess of 100°C and even in nuc­lear react­ors. The excit­ing ones for Mars are Lithoautotrophs. These are microbes that need water, heat and rock. They’ve already been found on Earth. They’re happy in what we would con­sider impossible con­di­tions, like 3km into the Earth’s crust. And there could be a lot of them, the mass of the deep bio­sphere might exceed the mass of the bio­sphere in the sur­face of the Earth. at the moment it’s too early to say for sure. If any of these were car­ried to Mars could they sur­vive? With the pres­ence of geo­thermal heat, and the pos­sib­il­ity of liquid water beneath the sur­face it’s entirely pos­sible. It is pos­sible that there’s a whole soph­ist­ic­ated eco­sys­tem beneath the sur­face of Mars.

It’s here I move from being slightly out of my depth to very out of my depth. If there is life on Mars and it’s dif­fer­ent to ter­restrial life then bio­lo­gists will be ecstatic because it effect­ively gives them access to entirely new mater­ial to test their idea on. However, if Earth and Mars have been shar­ing bio­lo­gical mater­ial, so that the life shares a com­mon ancestor then they will still be ecstatic.

Since the sev­en­teeth cen­tury Physics has under­gone a huge revolu­tion in dis­cov­ery because Isaac Newton provided a frame­work that has proven use­ful for build­ing new ideas on. It’s only since the early twen­ti­eth cen­tury that the work of Darwin and Mendel has been put together to achieve some­thing sim­ilar for Biology. Someone in the early eight­eenth cen­tury could not be expec­ted to pre­dict what would be achieved by the twenty-first cen­tury. Similarly it’s hard to say what the state of Biology will be by the early twenty-third century.

Zubrin fre­quently uses his­tor­ical ana­lo­gies with the col­on­isa­tion of North America in his book. The social sci­ences are the weak­est ele­ment of the book for me. A sec­tion on the Martian cal­en­dar being based on the zodiac is entirely spec­u­lat­ive and almost cer­tainly not going to hap­pen. He argues that the prom­ise of riches drew people out to the New World. He’s right to an extent, but as well as the pull of the New World, there was also a push. People were often not leav­ing to get a bet­ter life, but leav­ing to escape a worse one. Despite that I think he is right that if the eco­nomic incent­ives are there then col­on­isa­tion of space will hap­pen. To an extent it already has. Many of the satel­lites in orbit of the Earth are privately owned. There reason no people are up there for cor­por­a­tions is that there’s no prof­it­able reason why they should be. If there is a prof­it­able reason people will follow.

If you’re inter­ested in space explor­a­tion then I highly recom­mend Oliver Morton’s Mapping Mars and Robert Zubrin’s The Case for Mars. They’re both excel­lent and intel­li­gent books.

You can read more about the col­on­isa­tion of Mars at the Mars Society web­site set up by Robert Zubrin.

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When he's not tired, ill or caught in train delays, Alun Salt works part-time for the Annals of Botany weblog. His PhD was in ancient science at the University of Leicester, but he doesn't know Richard III.

2 Responses

  1. I can’t really see why we’d col­on­ise a piece of dead rock. Like build­ing a sum­mer house at the sum­mit of Everest.

  2. Alun says:

    To pre­vent the com­mun­ists from get­ting it! You wouldn’t want Mars to be a Red planet would you? :)