by Layla Kazemi
This article was written by a student at the Wheeler School. Brown's chapter of The Triple Helix collaborates with the Wheeler School to engage high school students in science journalism.
Does life exist elsewhere in the universe? Could life ever exist in the future and has it in the past? The possibility of other life in the universe has been speculated by the human race for centuries and is one of the most excogitated questions that humans face. Mars has been the focus of much of the research to answer this question because of the planet’s proximity to Earth, and although exploration of the planet began over half a century ago, the possibility of life on Mars is still as pertinent today as it was decades ago.
For the past couple of years, NASA has been working on a car-sized robotic rover named Curiosity to explore the Gale Crater on Mars. The rover successfully landed on Mars aboard the Mars Science Laboratory (MSL) spacecraft on August 6, 2012 and will spend a Martian year (687 days) exploring the planet. The goal of this project is to investigate and assess whether the area has ever had or still has environmental conditions favorable to life (1). So what exactly is necessary for a planet to be considered habitable? According to NASA, there are three conditions that are crucial for life to exist: liquid water, other chemical ingredients utilized by life and a source of energy (1). To search for the existence of these conditions the rover is using a strategy that NASA Mars exploration has used for years: following water (1). Since every environment on Earth containing liquid water sustains microbial life, this strategy makes the most sense. Researchers believe that the Gale Crater, where the rover landed and where it is conducting its research, was wet at some point (1). The exact location within the crater where Curiosity landed is near the foot of a layered mountain named Mount Sharp, which contains minerals that form in water and may preserve organics (1). This was determined thanks to five years of research by NASA’s Mars Reconnaissance Orbiter prior to the launch of Curiosity, a mission that evaluated 30 potential Martian locations for landing (1).
In order to achieve the mission’s habitability goal, the mission has four key science objectives. The first is to evaluate the biological potential of at least one target environment (1). To fulfill this Curiosity will investigate the nature and inventory of organic carbon compounds, search for the chemical building blocks of life, and recognize features that may record the actions of biologically relevant processes (1). The second objective is to distinguish the geology of the rover’s field site by investigating the chemical, isotopic, and mineralogical composition of surface and near-surface materials as well as understanding the processes that have formed the rocks and soils (1). Next, Curiosity aims to research the Martian atmosphere’s evolution, which dates about 4 billion years, and assess the present state of the Martian atmosphere in order to help determine past habitability (1). The fourth and final science goal of the mission is to characterize the broad spectrum of surface radiation (1).
To realize their objectives, the NASA team behind the project has equipped the rover with many high-tech instruments. Curiosity has a total of seventeen cameras that allow it to shoot high-quality photos and videos in black-and-white, color, and 3-D stereo (8). The rover’s main cameras are the two MastCams, which sit seven feet tall and provide images and videos of the surroundings (8). The two combine to take 3-D stereo images and full-color 360-degree panoramic images (1). To inspect Martian rocks and soil up close, Curiosity uses its Mars Hands Lens Imager (MAHLI) (1,8). This device works night and day to collect images using white light LEDs and ultraviolet LEDs (1,8). Atop the Curiosity’s mast, there is a rock-zapping laser and telescope called the ChemCam. The laser can hit rock or soil targets with enough energy to create sparks of plasma and the telescope then analyzes the spectrum of light to determine the chemical elements in the sample (1). Chemical elements are also gathered by the Alpha Particle X-Ray Spectrometer (APXS), and the Rover Environmental Monitoring Station (REMS) records information about daily and seasonal changes in Martian weather (1). Another important instrument is the Radiation Assessment Detector (RAD), which monitors high-energy atomic and subatomic particles coming from the sun, from distant supernovae and other sources (1). To help with the search for water on the planet, The Dynamic Albedo of Neutrons investigation, or DAN, can detect water bound into shallow underground minerals along Curiosity’s path (1). One instrument that has been heard a lot about in the news is the Sample Analysis at Mars (SAM), which uses a suite of three tools to analyze gases given off from the dusty sand when it is heated in a tiny oven (5). One of its key jobs is to look for carbon-based compounds that are the molecular building blocks of life on Earth (5). These are just some of the many incredible instruments specifically designed to achieve the mission’s science objectives and help it answer its main question.
With all the years of planning and developing, its countless impressive gadgets, and the two and a half billion dollars put in, it may seem like Curiosity will answer some of the lingering questions about the universe and be a revolutionary mission. It has even been dubbed “one for the history books” by a NASA scientist, but what has it achieved thus far (5)? The rover has been on Mars for more than half a year now, and although it is nowhere near answering the habitability question, Curiosity has already begun to probe deeper into the Red planet than ever before.
Within the first month of its journey, Curiosity found evidence for a stream that once ran vigorously across the area (3). Although there has been earlier evidence of the presence of water, this was the first time anyone had actually observed water-transported gravel on Mars (3). Curiosity also used its full array of instruments to analyze its first sample of Martian soil. The results found that the soil had a complex chemistry including water, sulfur, and chlorine-containing substances among many other ingredients (2). No firm conclusions could be made with this initial test, but the detection of the substances verified and confirmed the laboratory’s capability to analyze diverse soil and rock samples over the next two years (2).
Remnants of an ancient streambed on Mars. May or may not have been created by dinosaurs. [image via]
The first soil sample came from a drift of windblown dust and sand called Rocknest (5). CheMin's inspection of the Rocknest samples found the composition is about half common volcanic minerals and half non-crystalline materials such as glass (5). Water discoveries made by SAM also created lots of excitement because although water molecules bound to grains of sand or dust are not unusual, the quantity seen was higher than anticipated (5). SAM also found another important discovery. The presence of highly reactive chemicals called perchlorates might explain why it is difficult for Curiosity to find any organic molecules on its mission, since perchlorate reacts to heat and destroys complex organic molecules, leaving behind only carbon dioxide (5). These initial discoveries are just the start to Curiosity’s two years which will undoubtedly be filled with countless more pictures, samples, and discoveries. Going into the New Year, Curiosity already has big plans.
The majority of 2013 for Curiosity is going to be spent driving toward Mount Sharp located in the center of the ancient Gale Crater (4). The Martian mountain has a 3-mile high peak with compelling layers of rocks (4). Because Curiosity proved once again that water flowed through Mars at some point, and Mars has a source of energy, the sun, the last of the critical conditions needed to sustain life are chemical building blocks of life: complex carbon-based molecules (4). NASA scientists believe Mount Sharp will be the best place to look for these based on images taken from space prior to Curiosity’s launch revealing clues of fascinating geology (4). The voyage is said to take about nine months because Curiosity will continue to examine soils and rocks on the way there (4). Though we are only a few months into the year, in February, Curiosity confirmed that it had successfully obtained a sample from the interior of a rock (9). No rover on another planet has ever drilled into a rock and collected a sample, so this was a monumental achievement for the program and the science world (9). The particular rock chosen for the drilling may contain evidence of wet environmental conditions. Currently, the CheMin and SAM instruments, as well as several of the other instruments the rover is equipped with, are analyzing the sample to see what information it may provide (9). The year comes with great expectations for the robot and many experts are optimistic.
So, why should we as human beings care about Curiosity and its exploration? Is it really worth spending two and a half billion dollars on a robot that is not even guaranteed to answer our questions? And even if Curiosity finds that Mars was at some point or currently is habitable, what would that do? People in favor of the program argue that it is worth the investment because Curiosity could answer lingering questions about Earth’s history, reinforce U.S. prestige, and get more children interested in science (7). There is even serious talk of a plan to send humans to Mars by 2030 using information gathered on this trip, and if moon landings are considered some of the greatest events in human history, then landing man on Mars would likely surpass those missions (7). It would transform our view of what is possible and inspire millions of people around the world. Many argue that space exploration is one of the most effective ways to stimulate innovation and national momentum. Despite the abundance of potential beneficial outcomes, the expedition also runs some risks. Many are worried that if the rover actually does find microbes living in the soil, returning with the Martian soil could risk the spread of invasive species, and probably the most common worry is that the money will go to waste because nothing important enough will result from the expedition (6).
It is no secret that the opinions on Curiosity and space exploration in general can vary significantly from person to person. Some people hear news about Curiosity and roll their eyes, but it is guaranteed that the headlines are not going to end thanks to the millions of people who will always be interested in the possibility of other life in the universe. But to even those who are skeptical, Curiosity and its discoveries should be followed because they may in fact become instrumental in our understanding of life beyond Earth and what the future holds. After all, life cannot survive on Earth forever.