A Hitchhiker’s Guide to Astrobiology
|Aaron Gronstal, graduate student at the Open University in the UK, prepares samples collected from the Chesapeake Bay impact crater.|
You’re an astrobiologist standing in the centre of a vast, empty expanse of rock and dust pockmarked with impact craters. There’s no water here, no life, but your task is to collect data important for the study of life in the Universe. Douglas Adams, in his book "A Hitchhiker’s Guide to the Galaxy," said that "a towel is about the most massively useful thing an interstellar hitchhiker can have." In order to accomplish your task, you’ve packed an entire suitcase. The question is what did you bring?
The moon is a big, dead ball of rock and dust, yet its brilliant night-time glow has fascinated human beings since the dawn of our existence. Ask any person on the street what comes to mind when they hear the words "space exploration", and you’re bound to get one of two answers. They’ll either picture a large star-ship boldly going where only screenwriters can imagine, or they’ll recount the true-life images returned to planet Earth by human explorers on the moon. However, it’s been nearly half a century since Neil Armstrong made that historic step onto the lunar surface, and only 9 of the Apollo astronauts who sent back those inspiring photographs remain with us today.
In 2004, interest in human lunar exploration was sparked again when NASA announced the President’s Vision for Space Exploration, which includes specific goals for returning to the moon. But it’s not just the United States that has once again found itself enchanted by the light of the moon and the possibilities it may bring. Space agencies around the globe, from India to China and Japan to Russia, have announced their own plans for lunar exploration. The European Space Agency’s (ESA) most recent effort is the current SMART-1 mission, yet ESA is now looking at options for participating in lunar exploration that goes beyond robotics.
Tapping into the enthusiasm and expertise of Europe’s academia, ESA along with Alcatel Alenia Spazio in Italy released a "Call for Innovative Concepts and Technologies" in October 2005 that was focused on human lunar exploration. The aim was to draw on innovative ideas in Europe for an assortment of fields from in-situ resource utilization (ISRU) to nanotechnology. The funded studies looked at technologies that could become an important part of ESA’s own Aurora exploration programme.
But seeing as how the moon is known to be too cold for liquid water and covered in lifeless dust, what do astrobiologists have to gain from this newfound interest in lunar exploration?
Our team at the Open University in the UK was interested in what benefits could be gained in our field from a focused lunar exploration programme at ESA. We concentrated on lunar astrobiology, examining the primary astrobiology questions for lunar exploration and the tools that astrobiologists would need on the moon in order to perform scientific research. Although the study was based at the OU, the team consisted of researchers and university students from all over Europe and results of the project were recently presented at the Nordic Astrobiology Conference in Stockholm, Sweden.
Although the wise man said a towel is the most useful thing an interstellar hitchhiker can have, its usefulness for scientific discovery is limited. We were interested in figuring out what else an astrobiologist heading to the moon could not do without. The basic idea was to define an ideal suite of instruments that astrobiologists could take with them to any location – in short to create the perfect ‘astrobiologist’s suitcase’. The International Lunar Astrobiology Laboratory (ILAL) project drew on knowledge from researchers around the world in fields related to astrobiology by asking the question, "If you were stranded on a desert moon, what laboratory equipment would you want to have with you?" What resulted was a set of suitcases packed with tools for astrobiology on the Moon and beyond.
The three ILAL cases identified necessary laboratory equipment and highlighted specific instruments that require miniaturization for space exploration. Tools like Geiger counters and pH meters are already pretty small, but that’s not the case for instruments like Raman spectrometers which can weigh tens of kilograms. However, these large instruments are already being miniaturized for missions like ESA’s ExoMars and might be adapted for human use in a project like ILAL. Miniature equipment would then be durable, space ready, and small enough to be cheaply shipped to the moon. In addition, these same instruments would be beneficial for use in any astrobiology field site, from Antarctica to Mars. The instruments were divided into fields of study based on the responses from astrobiology researchers around the globe. The key areas of science identified for lunar astrobiology included: microbiology, geology and meteoritics, prebiotic chemistry, plant biology, human biology, and planetary protection.
The moon may not be a place where indigenous life can live and grow; but in protected habitats, life from Earth will adapt to the unique environmental conditions like reduced gravity on the lunar surface. Studying how microbes, plants and even humans adapt will be one of the major goals for astrobiologists on the moon. Understanding the adaptation of these organisms will be vital in ensuring the safety of human explorers if they live on the surface of the moon for extended periods of time. For instance, plants will provide much of the oxygen and food that will sustain human habitats, so understanding how to keep plants healthy will be of immense importance.
In addition, the moon can teach us a great deal about the history of Earth. Unlike the Earth, the moon has no surface recycling through plate tectonics and weathering, so when meteorites land on its surface they are preserved for millions of years. During the period of Earth’s history known as the Late Heavy Bombardment, our planet was blasted by thousands of meteorites. The remnants of these rocks from space are no longer visible at our planet’s surface, but some chunks of Earth may have been ejected from the planet during this tumultuous period and later landed on the moon. If we can find this Earth material on the moon it could provide direct information about Earth’s history at a period when life was just beginning. In addition, the moon may also hold pieces of other planets like Mars and Venus. In fact, it may be the only place where evidence of Venus’ early geology could be preserved today.
Another interesting aspect of lunar astrobiology is the potential for ice deposits in the polar shadows to contain evidence of prebiotic chemistry. Organic molecules like amino acids may have been formed in the early days of the moon when it was still volcanically active. These molecules are important for the origin of life, and could be preserved in polar ice today. Studying prebiotic molecules in a lunar laboratory would help us understand how they might form on comets or asteroids.
Finally, the moon would provide a perfect place for human explorers to practice astrobiology before heading to Mars. Because the moon doesn’t have its own native life, astrobiologists could develop safe practices for performing science without worrying about contaminating any native ecology. Protecting Mars from contamination will be a vital part of Mars exploration, and before astrobiologists can safely travel to the Red Planet we need to understand how to prevent Earth microbes from travelling with them. The moon may also be an excellent place to study materials brought back from Mars without having to worry about contaminating Earth. If there is microbial life on Mars, it may be better to study it in the isolation of the Moon rather than on our own planet’s surface.
The goal of the ILAL project was to provide the European Space Agency with a glimpse of how astrobiology studies may develop in the future alongside lunar exploration missions. The concepts defined by the ILAL team are a small piece of the necessary information that will help determine how scientific programs and instrumentation for lunar exploration could develop along with ESA’s Aurora Exploration Programme. There is a lot of excitement being generated around lunar programs all over the world, and the ILAL study showed that astrobiologists also have a great deal to look forward to in the future of space exploration.