The exploration of Mars was given a boost by NASA’s recent announcement that they had discovered liquid water on the walls of the Garni Crater. This was not a discovery from the well-known Mars Rovers, but rather the far less glamorous Mars Reconnaissance Orbiter. This space probe entered Martian orbit in November 2006 and has since be sending back invaluable data on the atmosphere, weather patterns, stratigraphy and cryology of its adopted planet; now it has added hydrology to its list of measurements with its confirmation of the recurrent seasonal flow of liquid water from hydrated salts on the crater walls. These salts appear to absorb what limited amount of atmospheric water Mars produces from the annual heating of its polar ice caps, stores them during the winter and then releases the precious liquid during the summer.
The presence of hydrated minerals and liquid water on Mars doesn’t mean that human habitation becomes an easy matter: Ma and Pa aren’t going to be packing up the homestead and striking out for Valles Marineris just yet. The planet is still strikingly more inhospitable than any place on Earth. But it does mean that Mars continues to be the highest priority in our solar system for the next manned mission. Whereas unmanned missions with robotic submersibles to Europa and Enceladus are highly promising and critically important enterprises, it is only Mars that combines the necessary factors for human life: water, an atmosphere, a reasonable temperature and it is our next door neighbor. The short transit to Mars is only 6 months, which is less than the voyage between Great Britain and New South Wales in the early 19th Century. Early pioneers seeking to cross the Great Plains to California could also be traveling for upwards of 6 to 9 months, timing their journey to avoid crossing the formidable Rocky Mountains in winter. The main difference, of course, is that these early pioneers did not have to take all of their air, food, water and fuel with them. We will, at least initially: but Mars will provide. Hydrogen can be combined with the carbon dioxide in the Martian atmosphere to provide us with methane, water and oxygen. Fuel and the basic necessities for human life through a process known for over 100 years.
Certain sceptics have remarked dismissively: “why bother with water on Mars? Better to take care of the water we’re exhausting here on Earth.” That is undoubtedly true, we cannot “world hop” like devouring locusts, and finding a sustainable model of human cohabitation with the rest of the terrestrial biosphere must be a priority. On the other hand, this outlook completely misses the point.
Even if we were the most conscientious planetary caretakers in existence, there is no guarantee that a giant meteor, a new zombie plague or the Rise of the Machines won’t wipe out humanity. In fact, the rapid advance of technology makes such long-tailed events more likely rather than less, so having a viable human population residing somewhere other than Earth vastly increases the probability of our species surviving the next 100 years;
Then again, we are not the most conscientious planetary caretakers, and the fact is that there will be 8.7 billion of us living on Earth before global population begins to slowly fall in 2055. We are therefore in a race to see whether population demand on resources and waste generation will increase faster than technological efficiencies. Or whether the growingly common and available nuclear technology will result in blasting ourselves to cinders;
Beyond the merely existential practicalities of species survival, how can we stop seeking for knowledge? How can we find so much evidence supporting the ubiquitousness of life in the universe yet turn away from it? For every Galileo, there is undoubtedly an Urban VIII, but that is not going to stop us – it never has.
Our goal should not be simply to land a few astronauts on Mars, conduct some research and then bring them home. Nor should Mars be exclusively “the Big Government Operation”, which has characterized the space programs of every nation until now. We have reached the end of that stage, however, and while NASA and other space agencies have a vital role still to play, we must now utilize the talents, ingenuity and energies of private enterprise and those intrepid individuals and families who will be the unsung, but vital pioneers crossing the gulf. That may sound like it’s still in the distant future or awaiting some as yet undiscovered technology, but it is not: we stand on the very cusp.
Our main impediment is that we live on Earth; and the Earth has a very significant gravity well. That imposes a costly burden on us: for every ton we need to lift into orbit, we need to burn 15 tons of fuel. This is known as the payload fraction. If we need to go further and leave Earth’s orbit, then the payload fraction rises even more and we need to burn 50 or 60 tons of fuel. It costs about $10,000 to move a pound into Earth orbit, but those first 100 miles cost as much to traverse as the following 141 million. The real trick is just getting off the ground; after that it’s not too difficult to get around the neighborhood.
There are some very promising technologies that could radically lower the cost for getting to Mars. One such is a recent patent submitted by Canadian firm Thoth Technology Inc. for a space elevator. The concept is exactly what it sounds like: an elevator to take people and materials up into space without the need for a rocket or expensive fuel. The idea is not new, it’s been around since the brilliant Konstantin Tsiolkovsky theorized it in 1895 (along with a great deal more that started modern rocketry). Until now, space elevator designs have failed due to our inability to manufacture a material both strong enough and light enough support their own weight. The Thoth patent is for an inflatable structure rising 12 miles above the surface, undoubtedly using a lighter-than-air gas like helium to reduce the structural load. Passengers and payload would then ascend the elevator – powered by electricity – to a platform where they would then take a space plane or rocket for their journey into orbit. Although not a true space elevator, the reusable Thoth structure could reduce the cost to orbit by 30%, possibly more. With projected costs per Mars mission in the billions, that is a very large savings.
Meanwhile, SpaceX has been developing a self-landing, reusable rocket. The Falcon 9-R variant of the successful two-stage delivery vehicle has undergone repeated testing and modification. On April 15th this year, a Falcon 9 attempted to land on an autonomous barge in the Atlantic Ocean. The rocket successfully executed a soft touchdown – only to topple over seconds later. Nevertheless, the ability to recover and reuse both stages of the rocket – within hours – would reduce the cost to LEO from approximately $55 million per launch today to only $5 or $6 million. Using the Thoth space elevator rather than a surface barge could reduce that to $3.5 million per launch. That would be an incredible game changer: it might not be within the average middle class budget, but it is not a lot of money and would put space within reach for many companies that today can only theorize about it. That would lead to further decreases in cost through innovation and scale. Given the pace of development, it seems likely that Elon Musk’s company will successfully complete development of the reusable launch system in the next few years.
Another important step forward is a propellant depot, an orbital gas station parked in low Earth orbit. One of the major obstacles in actually colonizing Mars, rather than just visiting, is the enormous amount of equipment that is required. If the equipment has to be launched from the surface, you either need a ginormous rocket or else you must reduce the amount of equipment, thanks to the inescapable payload fraction. And since the overall size of the rocket is limited by physical factors, you end with a very limited mission payload. With a propellant depot, however, you can assemble a much larger payload because you can tank up before you go. And you save money, because you can use much smaller – and cheaper – rockets to assemble the initial payload in space.
The propellant depot requires no still-to-be-discovered technologies to be built, but at this point there is no commercial reason to build one. There are design issues to be overcome, such as fuel boil-off and cryogenic embrittlement of materials, but these have solutions that are effective if costly. That’s where the “Big Government Project” approach makes sense: NASA could build and operate an orbital fuel station as an investment for the future. Like any other piece of critical public infrastructure, the point would not be to make a profit – though NASA would end up saving money over the life of the depot – but rather to enable others to go further than they might otherwise have gone.
Imagine a Mars mission using the increasingly common Dragon capsules – another SpaceX contribution – launched from a Thoth space elevator onboard a reusable Falcon 9-R rocket. The capsules rendezvous in low Earth orbit with equipment, supplies and personnel sent up separately and then mated to the rockets for the outward journey that are fueled in orbit at the propellant depot. Forget about NASA’s estimated 200 billion dollar Mars shibboleth – we could be sending people to the Red Planet for 2 billion per trip. If you think that’s a lot of money, just consider that we spent an average of 100 billion dollars per year on the 2003 to 2010 Iraq War: and those were only the direct costs. For the same amount, we could send perhaps 600 people per year to Mars – and bring them back as well, if they wanted to return. In a decade, we would have a fully functioning community with its own nascent economy and individual society. Within 50 years, it could be fully self-supporting: a Martian Republic that might be a new birth of freedom for this tired old Earth.
Many people, including me, would say that it would be a far better return on our investment as well.