Reflections after 50 Years of Space
A protege of Wernher von Braun, Jesco von Puttkamer has spent his long career working in human spaceflight. In this long essay, von Puttkamer gives his perspective on humanity's next steps into the universe. Here he discusses the lessons Mars has to teach us.
For the longer future, the significance of the ISS for the opening of a new era of peaceful cooperation between nations will undoubtedly be of considerably greater import that the important work underway on board today. In the wake of the process of worldwide restructuring and redefinition following the Cold War of yesteryear, ISS is acting as a catalyst for international understanding and collaboration. It helps to foster and form new partnerships among the nations of the Earth, to inspire our youth, and to stimulate and support the next generation of scientists, engineers, entrepreneurs and businessmen. It cannot fail in that because, fundamentally, it represents an answer to the age-old human drive for exploration of the unknown, the push toward new goals and frontiers. I'll return to this aspect below.
For human missions to Mars, the vision discussed here, the Space Station assumes a key position: as Residence in Space it will provide a kind of early bridgehead to the new continent outside Earth, to our next major goal, Mars.
First of all, relative to its development and operation, the ISS can be considered something like an early "demo" model for a major international Mars program in later years. Even more, as an orbital research and development facility it establishes and cements, in the longer range, the scientific and technical foundations of future human planetary missions. For the latter, it could also, with appropriate extensions, serve as a transportation node and port-of-embarkation.
As mentioned above, foremost among its research objectives are life sciences, particularly with regards to humans in space and all "human factors" associated with protection of health, well-being, and productivity of crews during extended stays in space - which do represent the toughest hurdles on the road to Mars. They are: the effects of zero-g and the development of potent countermeasures, protection against radiation, maintenance of stability and productivity of small multi-cultural groups of humans in close confinement and extended isolation, and the development of reliable closed-cycle life-support systems for multi-year missions. These missions also require new technologies such as aerobraking (to help conserve propellants by utilizing the atmospheres of Mars and Earth for flight maneuvers), storage and handling of cryogenics, (i.e., gases supercooled to liquid form), new spacesuits with greater flexibility and higher comfort for strenuous activity on the Mars surface, solar and nuclear power systems, and local-resources utilization for producing propellants and other substances necessary for life.
To shorten flight time and thus reduce the en-route exposure to microgravity and space radiation, human Mars missions will also favor nuclear propulsion systems. NASA is studying advanced nuclear propulsion concepts, and our Russian ISS partner Roskosmos is well advanced in the development of nuclear-electric propulsion.
Our exploration of the Red Planet is aimed not just at the search for life or later settlement by people but also at nearer-term objectives of quite concrete relevance for the present, motivated by fundamental questions such as why our Sun has planets in the first place, how is it possible that Earth and with it we humans exist, and is Earth's and our existence an extraordinary or normal occurrence in the cosmos? Why are we in this world, how did it come about, could it also have happened differently, and what will become of us?
Even more importantly, we are also exploring Mars in order to better understand our terrestrial environment, to improve our ability to more accurately determine what we are changing on Earth by our activities - on its surface and its atmosphere.
Mars is particularly well suited for such comparative planetology. The exploration of its topography, geology, geography, atmosphere, weather and climate conditions, developmental phases, indeed the entirety of its physical and chemical characteristics will add fundamentally to our knowledge and understanding of our own environment, thus serving considerably more than just the pure satisfaction of abstract human curiosity. Mars' formation and development still pose great riddles for science: It is the only other planet beside Earth with a surface clearly marked by complex geological processes caused by ice ages, glaciers, and flowing water in Niagara quantities. And that in a world which is so bone-dry today that all water in its presently considerably thinned-down carbon dioxide atmosphere would form a layer only two to five hundredths millimeter thick if it rained down to the ground all at once. Mars has ice fields, mysterious dark zones, bright "deserts", and various types of cloud formations which are subject to continual seasonal as well as sporadic changes.
It is a world full of wonders and mysteries, sculpted by processes the likes of which have been found nowhere else: it has the highest volcanoes and the greatest canyons in the solar system, with gigantic planetary sand storms, countless dry river beds, and vast, densely branched stream valley networks where water once rushed in torrents. It has polar caps of water ice and frozen carbon dioxide, and there is evidence of underground permafrost deposits and probably also reservoirs of water in liquid state. Methane gas was recently discovered to exude from the ground at certain locations, which could be a sign of underground biological activity.
Thus, it is not completely out of the question that even today adapted alien life forms might be found there. Mars, by all appearances, was created around the same time as Earth. But if these neighboring worlds had the same beginnings, how could it have happened that they took such distinctly different developmental paths? If scientific research discovers what actually took place when the climate on the planet changed so drastically, how long ago it occurred and why it happened, then we will clearly gain a better understanding also of the history and future of our own climates and environment.
One of the reasons for the difference is thought to be the phenomenon of plate tectonics, i.e., the shifting of the separate plates forming Earth's solid outer shell, the lithosphere: its complete absence on Mars could have been the key to the origin of its current conditions. On Earth, plate tectonics causes a vertical convection process continuously mixing the materials deep in the Earth's core, stoked by radioactive decay and the primeval heat of planetary formation; it thereby intimately connects the complex interactions of atmosphere and oceans with the biosphere. Thus, by inference, it appears possible that our plate tectonics could have brought about the Earth as we know it, including our life - all terrestrial life.
Has Mars a magnetic field like Earth? Or are we here, too, the exception among all Earth-like planets, perhaps because Earth with its iron core is the only planet in the inner Solar system sufficiently large and rotating fast enough to generate a significant magnetosphere? This question is of great importance for environmental research because our magnetic field, which shields Earth against energetic radiation from space, is possibly soon to undergo another plus/minus pole reversal as it did several times before in the past. During this process, unshielded space radiation would temporarily penetrate all the way down to Earth's surface.
How did Mars lose a large part of its atmosphere when it underwent its world-shaking climatic changes, and where has all the water gone? Is it underground? How significant is the fact that despite its carbon dioxide atmosphere, Mars shows no greenhouse effect like Earth? In other words, what are the consequences of that phenomenon for our own environment?
In order to reach such understandings, up to now mere theories which only now are being given substance by the counterexample of other worlds, we need the exploration of those planets -- and in the first place of our red neighbor.
Next: When are humans likely to set foot on Mars?