ExoMars Mission (2016-2020)

The ExoMars (Exobiology on Mars) programme is a joint mission of European Space Agency (ESA) and Russian Federal Space Agency (Roscosmos).  It is an astrobiology project to investigate whether life has ever existed on Mars. The term ‘exo’ in the ExoMars refers to the study of exobiology (sometimes referred to as astrobiology). The mission’s objective is also to demonstrate new technologies paving the way for subsequent Mars missions in the 2020’s.

What is exobiology?

The term ‘Exobiology’ was coined in the mid of the 20^th century by an American geneticist Joshua Lederberg, who is a Nobel Prize winner in Medicine. Exobiology is the study of the existence of life outside the earth to indicate the risk of bio-contamination associated with space flights which might in future contaminate and destroy bacterial ecosystems thriving in outer space and on other planets. It is also referred to as bio-astronomy or astrobiology. It also investigates the origin, evolution and distribution of life. The exobiologists aim to examine signs of primitive life especially on Mars.

Why Mars?

According to current scientific knowledge, Mars is believed to have/had the environmental conditions with liquid water and moderate temperatures which is apt to support complex organic molecules and possibly self-regenerated organisms.

Two missions under ExoMars programme

The ExoMars programme consists of two missions:

The first mission consists of the Trace Gas Orbiter (TGO) and Schiaparelli. The first mission was launched on 14 March 2016 and is scheduled to arrive at Mars in October 2016.

• TGO’s aim is to search for evidence of methane and other trace atmospheric gases which could be potential signatures of active biological or geological processes.
• Schiaparelli is an Entry, Descent and landing demonstrator module (EDM) which will be released by the TGO. It will make a controlled landing on mars and will test key technologies for ESA’s future missions to mars.

The second mission is planned to be launched in 2020. It will comprise of a European ExoMars rover and Russian surface science platform. The rover will carry a drill and other instruments dedicated to exobiology and geochemistry research.

What are the scientific investigations that are planned to be carried out under this programme?

• Search for signs of past and present life on Mars;
• Investigate how the water and geochemical environment varies; and
• Investigate Martian atmospheric trace gases and their sources.

What is so special about methane? Why its presence is always investigated?

Methane (CH₄) is an organic molecule which is present in the earth’s atmosphere in gaseous form. More than 90% of the methane found on earth is produced by living organisms. Recently, plumes of methane were detected in the northern hemisphere of Mars. This has evoked great interest because of its possible biological origin.

If the methane on mars turns out to be of biotic origin, then there may be two explanations of its origin:

• Methane produced by long extinct microbes which got frozen in the Martian upper surface and gets released into the atmosphere as there is a change in temperatures and pressure near the surface.
• Methane produced by some very resistant surviving methane producing organisms.

The methane if found, could also have an abiotic origin:

• Geological origin: Methane can be produced by the oxidation of iron which could have got trapped in solid forms of water.
• Methane can also be produced by a geochemical process called serpentinization.

In what ways India participates in the exploration of Mars?

India launched the Mars Orbiter Mission (Mangalyaan) on 5 November 2013. It was India’s first interplanetary mission and with it the ISRO became the fourth space agency to reach Mars. The success of this mission made India the first nation in the world to reach the Mars orbit in its first attempt. The Mangalyaan was launched carrying 5 scientific instruments dedicated to the survey of the planet. The instruments include a colour imaging camera, a thermal infrared spectrometer to get data on chemical composition of the surface, instruments to measure atmosphere, including a detector to search for methane.

A follow up mission called Mangalyaan2 with greater scientific payload is proposed to be launched between 2018 and 2020.