Does alien life exist? How can humans detect it if it does? These questions make us all ponder whether there is an extraterrestrial life. Are there any chances of existence? These all questions are the basis of Astrobiology.
WHAT IS ASTROBIOLOGY?
Astrobiology is an interdisciplinary scientific field concerned with the origins, early evolution, distribution, and future of life in the universe. It is the combination of molecular biology, biophysics, biochemistry, chemistry, astronomy, physical cosmology, exoplanetology and geology to investigate the possibility of life on other worlds and help recognize biospheres that might be different from that of Earth. It encompasses research on the origin of planetary systems, origins of organic compound in space, studies on the potential for life to adapt to challenges on Earth and in outer space.
The term was first proposed by the Russian (Soviet) astronomer Gavriil Tikhov in 1953. Astrobiology derived from the greek “astron” – constellations, stars “bios” – life “logia” – study, Exobiology is similar term, was coined by Nobel prize winner Joshua Lederberg. Exobiology is considered to have a narrow scope limited to search of life external to Earth, where as subject Astrobiology is wider and investigates the life between Earth and Universe.
While it is an emerging and developing field, the question of whether life exists elsewhere in the universe is a verifiable hypothesis and thus a valid line for scientific enquiry. Planetary scientist David Grinspoon calls astrobiology a field of natural philosophy, grounding speculations on the unknown in the known scientific theory.
WHAT IS HAPPENING IN THE FIELD OF ASTROBIOLOGY?
While astrobiology is a relatively young field, it has a secure and promising future. Astrobiology research has a significant impact on how agencies such as the National Aeronautics and Space Administration (NASA) and European Space Agency (ESA) plan for current and future space missions. For example, many recent missions have focused on exploring worlds in our own solar system for signs of past, present or the precursors of life, including Mars (Phoenix, Pathfinder, Global Surveyor and others) and Titan (Cassini-Huygens). At the same time, significant advances and investments in telescope technology (Kepler, James Webb Space Telescope) have allowed researchers to begin planning and searching for habitable planets outside our solar system.
In the United States, NASA and the NASA Astrobiology Institute (NAI) are leading policy makers and funders in astrobiology. An overview of the research goals and objectives they have articulated can be found in the NASA Astrobiology Roadmap. Internationally, astrobiology networks and institutes have been established in Europe, Australia, Canada, Mexico and South America, including the Centro de Astrobiologia in Spain, the Nordic Network of Astrobiology Graduate Schools, and the Australian Center of Astrobiology.
Research into the environmental limits of life and the workings of extreme ecosystems is ongoing, enabling researchers to better predict what planetary environments might be most likely to harbor life. Missions such as the Phoenix lander, Mars Science laboratory, ExoMars, Mars 2020 rovers to Mars, and the Cassini probe to Saturn’s moons aim to further explore the possibilities of life on other planets in the Solar Systems.
1. Viking program
The two Viking landers each carried four types of biological experiments to the surface of Mars in the late 1970s. The only mars landers to carry out experiments looking specifically for metabolism. Using robotic arms, it collects the soil samples into sealed test containers on the craft. The two landers were identical, so the same tests can were carried out at the two places on Mars’ surface; Viking 1 ans Viking 2 ; Viking 1 near the equator and Viking 2 further north.
2. Beagle 2
Beagle 2 was an unsuccessful British Mars lander that formed part of the European Space Agency’s 2003 Mars Express mission. Its primary purpose was to search for signs of life on Mars, past or present.
EXPOSE is a multi-user facility mounted in 2008 outside the International Space Station dedicated to astrobiology. EXPOSE was developed by the European Space Agency (ESA) for long – term spaceflights that allow exposure of organic chemicals and biological samples to outer space in low Earth orbit.
4. Mars Science Laboratory
The Mars Science Laboratory (MSL) mission landed the Curiosity rover that is currently in operation on Mars. Launched on 26th November 2011, and landed at Gate Crater on 6th August 2011. Objectives of mission are to help assess Mars’ habitability and to determine whether Mars is or has ever been able to support life. It collects the data for future human mission, study Martian geology, and climate. Also Opportunity (along with its twin Spirit) exploring Mars’ geology since January 25, 2004.
The Tanpopo mission is an orbital astrobiology experiment investigating the potential interplanetary transfer of life, organic compounds, and possible terrestrial particles in the low earth orbit. The purpose is to access the panspermia hypothesis and the possibility of natural interplanetary transport of microbial life as well as prebiotic organic compounds.
6. ExoMars rovers
ExoMars rovers is a robotic mission to Mars to search for possible biosignatures of Martian life, past or present. This astrobiological mission is currently under development by the European Space Agency (ESA) in partnership with the Russian Fedral Space Agency (Roscosmos).
- IceBreaker life : IceBreaker life is lander mission that proposed for NASA’s Discovery Program for the 202 launch opportunity, but it was not selected for development. One of the key goals of the IceBreakers life mission is to test hypothesis that the ice-rich ground in the polar regions has significant concentrations of organics due to protection by the ice from oxidants and radiations.
2. Journey to Enceladus and Titan : Journey to Enceladus and Titan (JET) is an astrobiology mission concept to assess the habitability potential of Saturn’s moons Enceladus and Titan by means of an orbiter.
3. Enceladus Life Finder : Enceladus Life Finder is a proposed astrobiology mission concept for space probe intended to assess he habitability of the internal aquatic ocean of Enceladus, Saturn’s sixth-largest moon.
4. Oceanus : Oceanus is an orbiter proposed in 2017 for the New Frontiers mission #4 travel to the moon of Saturn, Titan, to assess its habitability. Oceanus’ objectives are to reveal Titan’s organic chemistry, geology, gravity, topography, collect 3D reconnaissance data, catalog the organics and determine where they may interact with liquid water.