Engineering Life for Long Term Space Missions

Stories can inspire people to imagine and create the future. In fact, a lot of our predictions about the technology of the future come from science fiction stories. Take for example the mission to the moon in the novel “From the Earth to the Moon” published in 1865. Jules Verne tells the story of how the US sends 3 men to the moon, in a spaceship named Columbiad, launched in a rocket that weighs 9,000 kg at the cost of 12.1 bn dollars. 104 years later, in 1969 the US in fact sent 3 men to the moon in a spaceship named Columbia, weighing 11,000 kg, at the cost of 14.4 bn dollars. The list of science fiction inspiring today’s technology is long and although not all come true (sorry, still no lightsabers…), many of them are really accurate.

Stories can inspire people to imagine and create the future

One of the most popular subjects for science fiction novels are missions to and colonization of Mars. As a human species we have been setting our eyes on Mars for a long time. Many projects are currently under development. For example, Mars Direct is a project with the goal of starting a human colony on Mars within the next decade (1). In the same manner, NASA aims to have technologies to land humans on Mars by 2030 (2). In the private sector, Elon Musk, the CEO of Space Exploration Technologies Corporation (SpaceX) has targeted 2026 for a Mars landing with plans to establish permanent colonies(3). Maybe  one day the first generation of humans will contemplate a blue sunset on Mars, but before that could happen we have a long way to go. Because, the farther you go into space, the less you can depend on Earth.

Some of the challenges involved in a manned mission to Mars have already being addressed in science fiction. One of the most recent examples is the movie The Martian based on Andy Weir’s 2011 novel of the same name. In this story, a crew of astronauts accidentally leave behind one of their members on Mars. Stranded and alone on the hostile planet, he uses his scientific knowledge to survive. It is an inspiring movie and it makes you consider the situations we could encounter when removed from  our own planet.

One of the things that I immediately notice during the movie the Martian, was that in order to successfully establish a settlement on another planet we will need to travel with all of the essentials from Earth. However, carrying the equipment and people for long-term missions would require extra storage space in the spacecraft, which then requires extra transport fuel, increasing the cost of the missions. Given the technical challenges and costs associated with space travel, this approach would not be economically feasible in the long term. It made me wonder, how can we can make these missions more efficient?

mars sunsetMars’ sunset photographed from Gale Crater by the Mars Curiosity rover on April 15, 2015. Credit: NASA/JPL-Caltech (4)

Microorganisms may be a viable option. Humans have been using the products of microorganisms throughout our history (e.g. wine, bread, beer, yogurt). More recently the emerging engineering discipline of Synthetic Biology is showing promising results for the biological manufacture of pharmaceuticals, biofuels, food supplements, waste recycling and biomaterials. So why not use engineered synthetic microorganisms in outer space and extraterrestrial colonisation?

The goal of synthetic biology is to develop methods for programing new functions in living organisms analogously to robotic programming. Right now the field is still in its infancy and we are lacking a lot of the tools we need to reliably engineer biological systems. However research and investment in synthetic biology start-ups has increased dramatically in the past three years, heating up the discussion of this technology’s implications for our future (5).

Recent papers from synthetic biology pioneer Adam Arkin describe some of the technological and economical challenges of long-term space missions that could be addressed with synthetic living systems. In these studies, the authors looked at different areas: fuel generation, resource reutilization, food production, biopolymer synthesis, terraformation and pharmaceutical manufacture. The authors consider that microbial manufacturing could theoretically reduce the mass of fuel manufacturing by 56%, the mass of food-shipments by 38%, and the shipped mass for a habitat for a crew of six by 85%. Additionally, microbes could also be used to produce pharmaceuticals and other valuable products (6,7).

The challenge for synthetic biologists is that life has evolved on Earth and as far as we know, Earth is the only planet in our solar system that harbours life. Out there, space is cold and brutal. The harsh environmental conditions that we could face on Mars would not be suitable for most of terrestrial microorganism : low temperatures, low pressure (5-11 mbar) and high UV radiation compared to Earth. The atmosphere is mostly composed of carbon dioxide (95.3%), little nitrogen (2.7%) and oxygen (0.13%), and little water. Because of these conditions microbial cultures might require  enclosure in appropriate culture systems. However, some microorganisms already live in extreme environments on Earth, including deserts with similar conditions to Mars. Using directed evolution (directed evolution) and synthetic biology it could be possible to increase the versatility and resistance of microorganisms for Martian conditions in order to reduce culture control demands and risks of culture loss (8).

The big advantage of biological manufacturing is the reduced transport space. In theory these microorganisms could be contained in small tubes in a freezer or as dried endospores or akinetes, which conveniently do not require freezing during transportation and storage. Additionally, these microbes would encode whole processes in their DNA to transform simple starting substrates, such as carbon dioxide, water or minerals, into complex materials that astronauts on long-term missions would need.

Furthermore, research and investment to overcome these challenges offers great revenue. Economic analyses of NASA programs show ongoing economic benefits (such as NASA spin-offs) generating many times the revenue of the cost of the program. The “space economy” was assessed at 180 billion dollars in 2005 by the U.S. Space Foundation (9).

Aside from the technological advances, exploring other planets will greatly increase our knowledge about life on Earth and the perception we have of our planet. We are going out there to learn more about life on earth, our own world, and about our species.

The difference between science fiction and science is sometimes fuzzy and difficult to define but there is a definite boundary between science and fiction. Often, this boundary is relineatedback as science redefines fiction. Our sense of curiosity is what has challenged these boundaries and has guided the development of some of the most amazing technological advances. Things like engineering living organism for space exploration are becoming an everyday topic in the field of synthetic biology.

Our sense of curiosity is constantly pushing and changing the boundaries that distinguish science from science fiction. Experimental work in synthetic biology for space applications is just beginning but long-term manned missions are also further away in the future.  We must start guiding the future of applied synthetic biology for space exploration. This will require training and involvement of future generations of researchers, philosophers and citizens in all different areas of synthetic biology that will help to guide the transition of our world from a single planet community into one that extends well beyond.  After all, space is the final frontier.

–Post written by Ruben

References

  1.   Zubrin, R., Baker, D., & Gwynne, O. (1991). Mars direct – A simple, robust, and cost effective architecture for the Space Exploration Initiative. 29th Aerospace Sciences Meeting, 91–0326.
  2.    http://www.nasa.gov/content/nasas-journey-to-mars
  3.    http://www.space.com/31388-elon-musk-colonize-mars-now.html
  4.     http://www.nasa.gov/jpl/msl/pia19401/sunset-sequence-in-mars-gale-crater
  5.     http://www.nature.com/news/synthetic-biology-lures-silicon-valley-investors-1.18715
  6.     Menezes, A. A., Cumbers, J., Hogan, J. A., & Arkin, A. P. (2014). Towards synthetic biological approaches to resource utilization on space missions. Journal of The Royal Society Interface, 12(102), 20140715–20140715. http://doi.org/10.1098/rsif.2014.0715
  7.    Menezes, A. A., Montague, M. G., Cumbers, J., Hogan, J. A., & Arkin, A. P. (2015). Grand challenges in space synthetic biology. Journal of the Royal Society, Interface, 12, 20150803.
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