Saturday, 28 February 2015

Have spacecraft, will travel: planning the first manned Mars mission

As a space travel enthusiast since I was knee-high to a grasshopper it took me many years to appreciate robot probe missions with anything like the zeal engendered by manned spaceflight. As a schoolboy I watched the first space shuttle mission launch in 1981; no doubt like a multitude of others I initially considered this the start of the ‘casual' rather than pioneering phase of astronautics. Therefore it wasn't long before I asked myself the obvious question: when will there be a crewed mission to Mars?

Mars seems extremely familiar, no doubt due to the myriad of science fiction novels and films concerning the Red Planet. The last decade has seen a proliferation of news stories as various orbiters and rovers gather enormous amounts of - at times puzzling - data. However, none of the numerous projects of all scales that have investigated a manned mission have ever lifted off the launch pad. So here's a brief look at the state of play, not to say of course that this might not look woefully dated within the next few years.

1) Who will go to Mars?

Obviously the USA will supply the most funding so they will run the show. Or will they? The NASA budget available for planetary science is less than half that for International Space Station (ISS) operations, although of course the former are all unmanned missions. In fact, the Planetary Society has claimed that NASA spends less each year on interplanetary probes than the USA does on dog toys! A manned mission would have to negate this trend, as realistic estimates could be around US$500 billion for a single mission.

President Obama's announced half-billion dollar increase to the NASA budget is unlikely to be replicated by any Tea Party candidate who might (God forbid) achieve power. Unless that is we see a return to Cold War rivalries, with China offering a two-horse race to Mars. That might sound unlikely, but in 2006 the Chinese Government announced a long-term goal to land a crew there between 2040 and 2060. Since the US refused to allow them ISS involvement due to not wanting its technology to become available to Beijing, it is doubtful the Whitehouse would be any happier to cooperate in a Mars mission.

Either way, it's probable that some of the ISS partners would collaborate. However unrealistic it now appears in light of the financial crisis, back in 2001 the European Space Agency (ESA) announced its own plan for a crewed Mars landing in the 2030s. There was even a suggestion to include Russia as a minority partner, but the political situation there may prove prohibitive.

It doesn't just have to be other Western nations who participate in a NASA-led project, as numerous private companies are now involved in the commercial space programme. No doubt collaboration between some of the long-established aerospace giants and recent start-ups such as Space-X - whose long-term goal is to establish a Martian colony - with various Western governments would be more palatable to finance ministers. But it's still early days for the private sector: smaller infrastructure may shorten timescales compared to monolithic state enterprise, but as the Virgin Galactic SpaceshipTwo crash shows, developing even sub-orbital craft at this level still carries enormous risk.

So all in all, it could be the US and ESA, with or without substantial private investment, or China in a race with a Western bloc or (as an extreme longshot) Dutch engineer and entrepreneur Bas Lansdorp, whose Mars One mission plans to regularly send crews of four non-professional astronauts on a one-way trip to the Red Planet from 2025. So far he has raised about 1/8000th of the project's already shoestring budget, but that hasn't stopped thousands of would-be colonists from applying. In addition to the necessary privations, these volunteers would also be the subjects of a fund-raising reality television show. If doesn't sound even vaguely like the product of an insane society then I don't know what is. Perhaps we should just turn our backs on the rest of the universe and just spend our lives uploading selfies to social media sites?

2) What will happen?

In theory it sounds simple: a small group of professional astronauts with various scientific backgrounds will spend up to two years on a high-risk mission, exploring the Martian surface for perhaps a month or so, then bring back copious samples of rock, soil, atmosphere and ice for more detailed examination on Earth.

The BBC ‘s 2004 mockumentary Space Odyssey: Voyage to the Planets showed the deadly effects that ionizing radiation can have on interplanetary travellers. The Mars Science Laboratory, carrier of the Curiosity rover, spent the Earth to Mars transit recording the radiation levels. It confirmed that they were high enough to risk crew members contracting various serious conditions such as cataracts and cancer. Incidentally, female astronauts would apparently be more prone to radiation-induced cancers than male colleagues. A 2012 mission plan considered developing an electromagnetic anti-radiation shield, but most designs are looking to use traditional aluminium construction, perhaps with polyethylene shielding around the pressurised cabins. This definitely appears to be a case of fingers crossed as much as relying on advanced materials science.

The long duration spent in shipboard micro-gravity will also cause physical problems such as bone and muscle deterioration. The astronauts/cosmonauts/taikonauts (delete as preferred) will then have to adjust on Mars arrival to the one-third Earth gravity. As well as avoiding radiation on the Martian surface they will have to minimise contamination from the fine dust: minute particles suspended in the atmosphere could cause lung and thyroid problems if allowed into the lander cabin.

Besides the physical problems, the pioneering crew will also have to contend with the psychological effects of having travelled further from the Earth than any other humans - by an enormous margin. It's one thing to undertake a mission on the ISS - with a regular exchange of crew and a close-up view of the Earth via the cupola - but quite another to spend several years away from fresh air, blue skies, and all the other fantastic things we take for granted. The interplanetary distances would of course be exacerbated by the lack of real-time conversation: the one-way journey time for radio signals from the Martian surface is between four and twelve minutes.

There has been much research into astronaut's disturbed sleep patterns, which can obviously have deleterious effects on their work as well as their mental health. The claustrophobic conditions may contribute too: negative emotions blighted the small group of inhabitants of the Arizona-based Biosphere 2 sealed ecosystem in the 1990s. In addition, this experiment had distinct problems maintaining the environment, with a primary issue being the fluctuating oxygen and carbon dioxide levels. All in all, there are likely to be problems even the best planned mission won't have predicted.

3) When will it take place?

By comparison to low Earth orbit missions, a trip to Mars would be several magnitudes greater. If you want a pioneering aviation analogy I've just figured out that ratio of the Earth-Moon distance compared to the mean Earth-Mars distance is akin to the Wright Brothers' first flight of 36.5 metres being followed up by another spanning over 5 kilometres!

I can foresee two main issues to consider when planning mission timelines, which should ideally coincide to suggest an ideal launch window. The first is the relative orbital mechanics of the two bodies, which can be exploited so as to utilise a minimum fuel trajectory. The second relies on the eleven-year solar cycle: maximal solar activity helps to block interstellar cosmic rays and so reduce the risk of radiation poisoning. Although the sun's output would be at its peak, the astronauts would be safe from solar flares and coronal mass ejections providing they didn't need to undertake any spacewalks or surface EVAs for their duration.

There are several research projects that if one were to prove successful, could reduce by several decades the time before humanity is ready for its first manned Mars flight. The University of Washington and Lockheed Martin are both working on nuclear fusion technology suitable for such a mission. By reducing the journey time from between six and eight months to just three months there would be far less health risk to the crew, as well as presumably considerable weight savings on air and consumables.

Therefore it may become feasible as early as the 2040s but I doubt any earlier, regardless of how much advance is made in fusion technology. On top of all the usual political and socio-economic fluctuations there are just too many important longer-term issues that need resolution here first.

4) Where will it take place?

Mars, of course! The planet has a wide variety of locales (hint of travel brochure there), some rather more interesting than others. If the public get to vote on sites for exploration - bearing in mind that taxpayers will no doubt be funding the majority of the mission - conspiracy theorists and assorted nutbars might promote the curious tetrahedrons (note, not pyramids) of Elysium. Presumably they're enormous ventifacts, but they still appear to be very interesting geological features.

Then there's the great canyon system of Valles Marineris, over 4000 kilometres long and up to 7 kilometres deep. Or how about the 25 kilometre high Olympus Mons and its surrounding escarpment? In Pale Blue Dot: A Vision of the Human Future in Space, Carl Sagan suggested that it might be fruitful to explore the slopes of the Martian volcanoes in case they are scattered with diamonds ejected from the carbon-rich mantle!

Other locations that are just begging for detailed exploration are the polar caps, now thought to be mostly composed of water ice rather than frozen carbon dioxide, and caves or caverns, which would not only be a good place to search for native microbes but also to hide from radiation or dust storms.

5) Why will it happen?

This is perhaps the most difficult question to answer. Carl Sagan argued that the mission would fulfil the deep-seated need for exploration that our species - only recently converted from a nomadic existence - still feels. There is something to be said of this provision of a surrogate for human wanderlust, as identified in Bertrand Russell's 1959 quote: "a world without war need not be a world without adventurous and hazardous glory." This form of argument seems fairly mainstream in astronautic circles: even NASA's budget estimate for 2016 includes the phrases ‘reveal the unknown' (very likely) and ‘benefit all humankind' (which seems rather less obvious, except for Earth resources and weather satellites).

Against this notion are rather more pragmatic motives such as a combination of accelerated technological development and national prestige. But if nuclear fusion power is acquired in time for the first mission it's difficult to see what else will be gained from spending say half a trillion US dollars on a single crewed flight: wouldn't it be wiser to spend such vast sums on environmental stabilisation or medical research here on Earth? I've already commented on the potential white elephant of the ISS and there are no doubt many who don't consider any manned space exploration a suitable use of such enormous resources.

It's obvious that there are distinctive practical advantages to having humans on the spot rather than relying on robots. One issue that a single manned mission might be able to resolve that countless probes wouldn't is the question of life on Mars. The haze and plume seen in 2012 and the seasonal methane suggest some very interesting meteorological phenomenon if there isn't a biological explanation, but if there is any Martian bacteria then surely the mission could be deemed worthy of its immense budget? Somehow, I have my doubts…

One day in the next few centuries there could well be - unfortunately - branches of Starbucks and McDonalds on Mars and the Red Planet will be an alien frontier no more. But until then, any humans who undertake such an incredible journey will be pioneers in the Yuri Gagarin/Roald Amundsen/Edmund Hillary mould. However, I doubt the first human to step onto the Martian surface will use the latter's keen Kiwi phraseology: "we knocked the b***d off!"