ASTROBIOBOUNDS: SEARCH FOR LIFE IN SOLAR SYSTEM

Our solar system is one of over 500 known solar system in the entire Milky Way galaxy. According to available data, it is came into being about 4.5 billion years ago on the cloud of interstellar gas and dust collapsed resulting in a solar nebula, a swirling disk material that collided to form the solar system. It is located in Milky Way’s ORION STAR CLUSTER. Only 15% of stars in a galaxy hosts planetary system and one of those stars is our own SUN, revolving around are 8 planets which are further divided into two categories based on the composition.

One marked as TERRESTRIAL which includes Mercury, Venus, Earth, and Mars, and the other as JOVIAN which includes gas giants, the Jupiter and Saturn and Ice giants, the Uranus, and Neptune. The Gas giants are predominantly made up of helium and hydrogen and the Ice giants also contain rock, ice, a mixture of water, methane, and ammonia.           

The possibility of extraterrestrial life is a tormenting idea long prompting our species to wonder if there are other worlds where life exists. Now as space technology advances the chances of finding it are greater than before.

All planets of our Solar system
The Solar System

The search for life:

The search focuses on the following three ingredients:

  • The first one is life’s basic chemical building blocks made from simple elements found in a cloud of gas and dust that gave birth to all the planets and moons these chemicals were possibly delivered throughout the solar system billions of years ago by comets and asteroids, called organic compounds, consist of carbon, oxygen, hydrogen, and nitrogen.
  • Another prerequisite for life is the Water that allows these compounds to mix and interact.
  • The third ingredient is the energy source like the SUN to power the chemical reactions that make life possible.

Scientists were once convinced that all three ingredients could only be found if planets lie in the habitable zone of its host star, the Sun. But now missions to the outer solar system are calling this assumption into question.

A logo of NASA's Mars exploration rovers
Photo Credit: NASA, JPL

 LIFE ON MARS 

The search for life on Mars has basically two main themes. The first one is the presence of liquid on its surface early in history and some of the processes that were important for the origin of life on Earth may have also been active on early Mars. The second important thing is access to ancient rocks which analysis help us to know about the origin of life.

Mission to search for life on MARS               

  • Spirit rover                                                                               
  • Opportunity rover                                                                          
  • Curiosity rover

Spirit Rover (MER-A)

One of the twin rovers launched in 2003 on 10 June from the Cape Canaveral Air Force Station, Florida. It landed on 4th January 2004 on Gusev Crater of Mars started searching signs for ancient life. Among her countless discoveries, Spirit found evidence that Mars was once much wetter than it is today and helped scientists better understand the Martian atmosphere.

Discoveries made by this rover includes the finding out of silica patches on landing site which suggests the possibility of microbial life existence as silica is thought to be produced from hot-spring and fumarole type environment which on earth known to be facilitating the microbial life.

        “The concentration of silica is probably the most significant discovery by Spirit for revealing a habitable niche that existed on Mars in the past.”

Stevee Squyres, prinipal investigator for the rover

                                                                                                                                         During its stay on Red planet, it helps scientist to understand the temperature of Martian Atmosphere which further helped in designing of future spacecraft. The discovery of “Husband hills” was also a remarkable achievement. These Hills covered with carbonates of Iron and magnesium and show the interaction of Water and Magma.         

The husband hills found on Martian surface.
The discovery of “Husband hills” was also a remarkable achievement. These Hills covered with carbonates of Iron and magnesium and show the interaction of Water and Magma. 

Rover gets entrenched in soft soil at a site, named as “Troy” on May 2009 and recovered with only five working wheels during the rescue efforts.  The Spirit Mission ended on May 25, 2011.

OPPORTUNITY ROVER (MER-B)

The opportunity rover launched in 2003, the second rover being launched from the Cape Canaveral Air Force Station, Florida in the same year to land on the Red Planet. It landed January 25, 2004, at Terra Meridiani. It was also intended to search for signs of ancient life.  Although it planned as a 90 days mission but outlasted her duration and made the whole bunch of discoveries during its stay on Martian terrain. 

The opportunity rover at Martian surface
 Opportunity Rover

The discoveries include the finding of the dramatic evidence related to the presence of water on at least one area of Mars for a certain period and after analysis of a collected sample of soil and surface material it assumed that microbial life might have been existed due to suitability of conditions for their survival.

In June 2018, during its stay on Mars it had encountered with severe Mars-wide dust and as a result the communication with earth gets hindered. But later on, it was restored by the effort of engineers in the Space Flight Operations Facility at NASA’s Jet Propulsion Laboratory (JPL). By using more than a thousand commands they were finally able to restore the contact and on 13th February 2019, the Opportunity rover gets revived. On 10 June rover’s final communication received. 

Curiosity rover

Originally known as the Mars Science laboratory NASA’s Curiosity Rover is part of a global effort to research the history of Mars specifically what happened to its water. It was launched on 26th November 2011 from Cape Canaveral and on 6 August it landed inside Gale on Mars at the place of Aeolis Palus. Mars is a dried and dead world with only its polar icecaps for evidence that there was ever water.

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 Curiosity Rover Spacecraft

The remarkable achievements of curiosity rover include the landing with unprecedented precision as compared to NASA’s twin Spirit and Opportunity rovers. Another great achievement was the measurement of Martian radiations which help scientists to understand their hazardous effect to both human and microbial life. Ancient streambed was also discovered just after the seven weeks of landing which suggests the presence of some habitable parts of Mars.

  “We have found a habitable environment that is so benign and supportive  of life that probably — if this water was around and you had been on the planet, you would have been able to drink it,”

John Grotzinger– Curiosity chief scientist, of Caltech in Pasadena

Cassini Huygens mission:

In 1997, a collaboration between NASA and the European and the Italian Space Agencies, launched the Cassini space probe on a seven-year journey to reach Saturn. The probe designed to study the entire Saturn system including its rings and natural satellites for the search of life, nonetheless, Cassini didn’t make the seven-year journey on its own. Attached to the space probe was a small lander, Huygens which considers as to become the first spacecraft to land on Titan. Several months after entering Saturn’s orbit, Huygens separated from Cassini and started its journey towards Titan and started sending back vital details about Titan’s environment.

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Cassini-Huygens assembly

 As it descended Huygens recorded accelerometer data, which could be used to deduce properties like the density of the fluids as we knew the aerodynamics properties of the probe. It took temperature and pressure readings to teach us about the thermodynamic properties of the atmosphere. After two and a half hours of descending through the unknown, Huygens successfully landed on the surface, making it the furthest spacecraft landing from earth ever completed. Although it was only designed to survive for about 90 minutes whilst on the surface, Huygens successfully recorded and sent back 350 images, revealing a world eerily similar to ours, with sharp hills and valleys and rivers of methane cutting their way through the landscape.

The Saturn’s largest moon ‘Titan’, although it’s about half the size of earth, Titan has the characteristics that we think are very similar to earth in its early days. Titan has a thick atmosphere at around 4.4 times denser than Earth’s and is the only moon in the solar system to have any noticeable atmosphere at all.

Dragonfly Mission

As our quest to learn more about the origins of life countries, NASA’s new mission called ‘Dragonfly’ will begin its journey to Titan in 2026, and the work of the Cassini and Huygens mission will be vital to its success.

Dragonfly is a mobile lander filled with eight large rotors that will help to fly around the surface like a drone. An incredibly difficult engineering challenge and the data gained from Huygens will be insanely valuable when designing the drone. Everything from its sensor layout, battery capacity, energy source, and propeller design will be dictated by what we learned, and those are exactly the engineering challenges we are going to investigate. It would have many of the same scientific instruments as the Curiosity Rover for the search of life.

 Multiple views of the Dragonfly dual-quadcopter lander
 Multiple views of the Dragonfly dual-quadcopter lander

When it lands seismometer will give us information about quacks and reveal the thickness and nature of Titan’s icy crust sitting above which is thought to be liquid water ocean as Cassini witnessed the surface shifting in position by 30 km in just two years indicating that the crust is floating on top of some kind of liquid layer. We are also looking forward to the amazing photos of Titan’s surface. Since the air is thicker on Titan and the gravity is one-seventh of the earth the Dragonfly would be able to achieve more thrust on a planet that needs less lift which ultimately reduces the required energy.

Europa Multiple Flyby Mission

NASA has announced plans to send spacecraft to Jupiter to explore one of its moons EUROPA, search for life in this potentially habitable world. According to CNN Europa, one of Jupiter ‘s 62 known moon is thought to be one of the most likely places in our solar system to support life because of the presence of water beneath the surface.

Europa Clipper spacecraft
Europa Clipper spacecraft

NASA’s planned to send a spacecraft for around 45 flybys of Europa and it would take years to get there but would be able to take high-resolution images that would hopefully allow scientist better to understand the makeup of the icy surface of Jupiter. The plan is currently entering the development stage. By exploring the Europa and ocean worlds would help the scientists to know about the existence of biology beyond the Earth surface. 

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