Welcome to our 200th blog posting. It seems appropriate to write this article on a milestone date in the advancement of human technology in space. For today is the day that NASA’s Mars Science Laboratory, known also as Curiosity, has arrived on the surface of Mars to begin its planned two-year mission to study the history of that planet in a place where there is geological evidence of the presence of water in the past.
In previous entries to this blog site I have written a number of articles describing our efforts to unlock the secrets of Mars. The Viking missions of the 1970s left scientists with a quandary. Were the experimental results evidence of life or of a unique Martian chemistry? When Phoenix reached Mars and uncovered water ice and witnessed snow falling in the Martian atmosphere we were once more astounded by what seemed to be such an Earth-like world. And yet Mars is far from Earth and very much unlike our world.
Through Curiosity and its on board science laboratory we will gain a more comprehensive understanding of the chemistry, soil and atmosphere of Mars, and in its wake will set the stage for future missions including those by humans.
What Curiosity Has Taught Us Already – Radiation in Deep Space is a Problem
One of Curiosity’s tasks involved measuring radiation in transit on the way to Mars. Designed with a radiation protection shell capable of reducing exposure by 99%, over the eight months en route the amount of radiation penetrating the spacecraft recorded by the Radiation Assessment Detector or RAD was significant. Considering a human mission to Mars involving a two-way trip plus a significant period of time on the planet’s surface, the kind of radiation exposure any human crew would receive could prove lethal.
Curiosity’s RAD was switched off just before landing but will be turned on again as it begins its mission on the planet’s surface. We will know a lot more about the risk to human missions on the surface after studying the data we receive. But what we know now in terms of the cosmic rays and solar particle storms is that the existing designs of spacecraft for any human Deep Space exploration need to be altered radically to address the risk.
The Technology to Send Human Crews to Mars
Missions to Mars, inhabiting Mars, for many here on Earth this seems a pipe dream. The cost measured in hundreds of billions of dollars by NASA. The scientific and technological advancement marginal, say the critics, when compared to what we could do with artificial intelligence and robotics. Some even argue that we can have a virtual presence on Mars through intelligent robots. And some believe uploading our minds to robotic brains may give us the means to experience Mars without dealing with the frailties of our human bodies when confronted with the harsh realities of Deep Space and the Martian surface. You can read Mike Wall’s article about reasons for not going to Mars and begin to draw your own conclusions.
Or you can read about those who dream about exploring and settling on Mars fostered by groups like The Mars Society, a non-profit international organization, and Mars One, a Dutch private venture, the latter intending to begin colonizing Mars in 2023. Getting there, however, is as much a challenge as surviving once we arrive. What will it take?
1. Lots of fuel. Today’s chemical-based rockets expend enormous amounts of fuel to escape the gravity well that is Earth. A spacecraft using chemical rockets on a mission to Mars would also have to carry propellant on board for trans-Mars navigation adjustments and for slowing down once in the vicinity of Mars to achieve orbit. Then there would be the need for fuel for a Martian lander and fuel for launching from the surface to rendezvous in orbit for the return home – even more fuel. We could use celestial sleight of hand to plot a course that reduces the amount of time to get to Mars and, therefore, the amount of fuel, or we could use aerobraking techniques to limit fuel requirements in our approach to Mars. We can even manufacture the fuel we will need for the return trip from Mars once we arrive on the planet’s surface. But what we cannot do is ignore the reality of the amount of fuel we will need.
2. A new propulsion system that is not chemical based. There are a number of choices. VASIMIR, which you can read about in a previous article on this site, is one. Nuclear Thermal Engine technology such as NERVA is another. Antimatter-based propulsion may be a third.
3. A new type of spaceship that is more than a crew capsule. Any long-duration space mission needs to provide better cosmic ray and solar radiation shielding than anything currently on the shelf from any space agency or commercial space operator. It also needs to address the issue of long-term human exposure to micro-gravity. Nautilus-X MMEV is an acronym with cachet. It reminds us of Captain Nemo’s Nautilus but actually stands for Non-Atmospheric Universal Transport Intended for Lengthy United States X-ploration Multi-Mission Space Exploration Vehicle. The Nautilus-X features a toroidal ring that produces artificial gravity, hydroponic farming on board, docking ports, radiation shielding, manipulator arms, solar panels and landing craft. Designed to be built in low-Earth orbit and then moved to a way-point between Earth and the Moon, it would be mated to an advanced propulsion system such as VASIMIR or NERVA and sent on its way.
The Why and When of Mars
Viking landers in the 1970s provided us with a dilemma. One experiment showed a chemical reaction consistent with biological existence. The other did not. We have never gone back to repeat the experiment. Instead we have in subsequent missions to the Red Planet, looked for telltale signs of water, an essential medium in which life exists on Earth. And what we have discovered is that Mars has lots of water, not oceans, but subsurface water that occasionally surfaces and evaporates. We saw this evidence with the Phoenix lander and we are seeing it in photographs taken by Mars orbiters.
We want to go to Mars because finding life there, either in existence today, or in the geological record, tells us that in our Solar System two planets out of eight, not one, gave birth to life. Knowing the meaning of that statistical coincidence alone will change our perspective about life elsewhere.
Creating human settlements on Mars and the technology necessary for these settlements to thrive is a good bet according to Stephen Hawking. “The human race shouldn’t have all its eggs in one basket, or on one planet,” he recently stated.
Of course in inhabiting Mars we will be married to the technology that supports our existence in a very different way than here on Earth. Will we get there by 2023? More than likely not. But humans will be not just exploring by living on Mars by mid-century.
Will we terraform the planet? To some degree in the same way we have altered Earth through our human activity.
What will Mars be like in 2100. When we turn our Earth telescopes to focus on Mars we will see the lights of human settlement. And the people of Mars, born in a low-gravity environment, in many ways very different and in many ways the same as us, will be looking outward further to the next step in our human space journey.
Mars will change us forever.