GSLV Mark III: Outstanding Scientific Acheivement by ISRO

India’s heaviest rocket launcher GSLV (Geosynchronous Launch Vehicle) Mark III successfully blasted off on its maiden flight from Satish Dhawan Space Centre, Sriharikota on Dec 18th. The liftoff was flawless bolstering India’s ambitions of manned space missions. The 155 crore mission designated LVM3 was conceived to study the flight validation of the newly developed GSLV Mark III and to test the ability of CARE (Crew Module Atmospheric Re-entry Experiment) module to enter earth’s atmosphere with thermal resistance, parachute deployment in cluster formation, aerobraking systems and apex cover separation procedures. GSLV Mark III is the third generation upgraded vehicle marking the third generation of India’s orbital launch systems. It is designed to place 10 tonnes of pay load into Low Earth Orbit (LEO) or 4 tonnes to geosynchronous transfer orbit (GTO). Till now India’s, workhorse PSLV (Polar Satellite Launch Vehicle) with its reliability in delivering small satellites earned not only great repute but revenues to the country. With this success India’s dependability on foreign launch vehicles will be reduced saving millions of dollars expended for deploying bigger payloads. India can emerge as a smart scientific power in the business of global satellite launching.

India’s odyssey to space began in 1979 with an unsuccessful attempt to launch Rohini Technology pay load (RTP) using the Satellite Launch Vehicle (SLV) whose payload carrying capacity was only 90 kilograms. It was soon replaced with an upgraded version of Augmented Polar Satellite Launch Vehicle (ASLV), a five stage engine with solid and liquid fuels that could carry a pay load of 150 kg. However, the ASLV development plans were aborted soon as ISRO made a mid-course correction to move over directly to develop the next genre of launch vehicle, PSLV capable of launching 1600 kg satellites in 620 km sun-synchronous polar orbit or 1050 kg satellite in GTO. PSLV has four stages that use solid and liquid propulsion systems alternatively. With an exception of maiden unsuccessful flight, since its inception in 1993, PSLV successfully launched 58 (23 Indian and 35 foreign) satellites.

GSLV was introduced in 2001 to enable India to deploy its own communication satellites of INSAT-4 class. The vital final/third stage of GSLV, is cryogenic stage, which is highly efficient than the liquid stage in PSLV. Despite concerted efforts, the success rate with GSLV has been 37.5%. GSLV mission received a major boost with flawless deployment of GSAT-14 in January 2014. GSLV Mark-III is the next generation rocket and its current sub-orbital flight is aimed at validating the two stages of the rocket. The cryogenic third stage is passive.

LVM3 weighing 630 tonnes and 42.4 meters at liftoff is a three stage rocket. The first stage contains two S200 Large Solid Boosters (LSB’s) that burn 207 tonnes of solid propellant- mixture of ammonium percholate, aluminium and hydroxyl terminated polybutadiene (HTPB) and fired for 130 seconds. The second stage is liquid or L110 powered by two Vikas engines derived from France’s Viking series used on Ariane rockets. It burns asymmetrical dimethyhydrazine (UDMH) oxidised by dinitrogen tetraoxide and will be air-lit two minutes after the rocket lifts off under the pressure of two solid boosters. The Third stage designated as C25 powered by CE20 engine burning liquid hydrogen and liquid oxygen. During the current flight, it is inert and loaded with liquid nitrogen to stimulate propellant.

The payload is the Crew module, a prototype capsule designed by ISRO for India’s manned space programmes. The primary objective of the crew mission is to validate the re-entry and recovery of the spacecraft. The 3,735kg cup cake shaped capsule capable to carrying 3 crew members is attached to the third stage upside down and flew without the service module that accompanies manned missions. By launching upside down, ISRO hopes to simply the CARE mission and increase the chances of success. This is the second spacecraft to undergo a flight test this month. Earlier on December 5^th NASA carried out Exploration Flight Test 1 to validate the Orion spacecraft. But NASA’s Orion was highly sophisticated than CARE and made two orbital trips around earth and made a re-entry from apogee of 5880 km. Even the re-entry velocity of Orion was much higher. But both mission had similar objectives of testing the spacecraft’s performance during re-entry and validating recovery procedures. GSLV accelerated CARE to a speed of 5.3 km/sec and it separated from the vehicle at an apogee of 126 km. After separation from the vehicle, CARE activated its control systems. Following its entry preface with earth, drogue parachutes were deployed which slowed the descent of the capsule and main parachutes swung into action when it was 3 km from above the Indian Ocean. Capsule splashed 180 km away from South of Andaman & Nicobar Islands. The next flight of GSLV Mark III is scheduled for 2016 when its cryogenic phase will be ready.

ISRO with its relentless scientific pursuits has opened up new vistas for scientific exploration. This glorious accomplishment would augur missions like Chandrayaan-2 and human space missions. But the dream of putting Indian astronauts into space and its feasibility is still highly debated and is subjected to allocation of 12,500 Crores from the government.

  

CARE (Crew Module Atmospheric Re-entry Experiment) module

 

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Evolution of Birds Unravelled

Scientists have arrived at momentous juncture wherein they have completely sequenced whole genome of 45 different existing bird species to answer the little known origins of the Birds. Children who are unassumingly attracted by the veracity of the dinosaurs, perished when an asteroid stuck the earth 66 million years ago. This catastrophe eventually facilitated the evolution of mammals which dominated various niches of earth left vacant by the extinction of the gigantic dinosaurs. Studies of the fossils and the genome sequencing indicated that nearly 10,000 species birds might have descended from theropods, the two-legged dinosaurs which include Tryannosaurus rex that survived the extinction. Over 200 scientists from 20 different countries have collaborated to create evolutionary tree that reveals the exquisite features of the birds like the colourful plumage, loss of teeth and their ability to croon songs. Genetic codes were used to understand a wide range of issues- related to brain functioning, learning concepts, reconstruction of ancient ancestor of birds and if had evolved from dinosaurs.

Overwhelming fossil evidences suggested that birds evolved from small predatory dinosaurs. Scientific theories undergo constant change. The fluctuating nature of science is attributed largely to knowledge which is being constantly upgraded in the face of new evidence and with availability of new technology. Members of the project, Avian Phylogenomics Consortium who developed the Avian family tree published a series of 8 papers  in the latest edition of Science magazine and in more than 20 different scientific journals. To begin with scientists started extracting DNA from finger nail sized pieces of frozen flesh of 45 different species gathered from different museums of the World. The DNA was then subjected to the painstaking genome sequencing. Tonnes of the sequence information was fed to 9 super computers (the equivalent time of 400 years of processor time) to compare all the genomes and align them into a comprehensive family tree. The construction of the bird family tree is a spectacular achievement and it was produced by amalgamating the new information with the previously published sequences of Zebra Finches, domestic turkeys and chickens. Rapid decline of cost of genome sequencing after 2007 and tremendous computing power of beefy super computers which sifted through the tonnes of the genomic sequences made the large scale genomic analysis possible. It indicated that NeoAves the order that contains nearly 95% of the modern birds arose spectacularly and paved way for evolutionary opportunity just few million years after the asteroid collision.

Genomic analysis has indicated that distinctive bird characteristics like the feathers, flight, endothermic physiology, unique strategies for reproduction and growth and novel pulmonary system might have evolved from the Mesozoic terrestrial dinosaurs. Studies in developmental biology and other disciplines also complemented the crucial evidence about the origin and development of various bird characteristics. Modern extant bird orders during the major part might have undergone a gradual and step wise transition with occasional bursts of morphological novelty. In addition to birds three orders of nearest ancestors of crocodiles were studied to logistically understand the origins and evolution of birds. While birds evolved at similar rate as mammals bird genomes are one-third the size. They are similar to mammals in their capacity for vocal learning. The genes identified for vocal learning in birds could provide a clue in rectifying the problems of stuttering or Parkinson’s disease in human beings as well. While water birds had lowest number of genes linked to feather colouration domesticated and agricultural birds had eight times as many genes. Common ancestor of all living birds lost teeth 100 million years ago. The most primitive chromosome pattern revealed that domestic chicken is the closest relative to a living dinosaur. The research threw light on penguin’s (Emperor and Adelie) ability to adapt to frigid conditions. The gene DSG1 that causes thick skin on feet and hands in humans is present all over the body in penguins. They evolved 60 million years ago, lost the ability to fly but their wings have become adaptable to underwater acrobatics.

These genome wide studies unravelled some important titbits in the evolutionary cycle. Birds evolved rapidly than their close crocodilian ancestors which remained largely unchanged over 100 million years. Studies indicated that “archosaurs” which lived 240 million years ago was common ancestor of reptiles, birds and dinosaurs. Evolutionary rates greatly help palaeontologists to estimate the generation time or how soon an animal can reproduce. Slower evolutionary rates go hand in hand with longer generation times. Scientists were able to reconstruct about half of the archosaur genome based on the reptile and bird genome analysis. Though the DNA of archosaur was lost to history they were able to reconstruct genome code and generation time. This first ever comprehensive whole genome analysis of birds resolved lots of fundamental questions and the genome information helped to re-evaluate which species are related.

ISRO getting ready for the crucial GSLV test flight

ISRO is getting ready for the crucial testing of the Geosynchronous Launch Vehicle Mark III (LVM3-X mission) which is expected to lift off from Sriharikota (SHAR) on December 18^th between the launch window of 9am to 12 am. India’s aspirations for deep space and putting bigger satellites into the Geo Transfer Orbit (GTO) had been contained by the absence of reliable launch vehicles. To give a major fillip for launching communication satellites and further manned crews into the space, ISRO is working relentlessly to develop the GSLVs.

The 155 Crore experimental mission with upgraded GSLV is the heaviest and most powerful launch vehicle capable of placing communication satellites of INSAT-4 class kind of satellites weighing 4-4.5 tonnes into GTOs. The earlier GSLV Mark II vehicles could carry INSAT-II class of satellites weighing 2-2.5 tonnes. Mark III 42.4 meters tall and weighing 630 tonnes at launch is double the weight of the existing GSLVs. This experimental mission carrying the crew module into the suborbital space 125 km from the surface of Earth will attain speed of 5.3 kilometres per second, is aimed to test the atmospheric stability of the rocket. The improved GSLV has reduced number of propulsion modules which increase the reliability of the launch vehicle and reduce the launch costs. It has four propulsion modules against the seven of its GSLV predecessors.

GSLV Mark III has three different stages. The first stage contains two S-200, Large Solid Boosters (LSB), with 200 tonnes of Solid propellant is the largest in the world, flanking the large liquid propellant stage. LSBs burn for 130 seconds and generate about 5,150 kilo newton thrust. They are equipped with flex seal which helps in correcting the orientation of rocket. Only the American space shuttle, Titan IV-B and Europe’s Ariane 5 has more solid propellant than GSLV Mark III. Of these only Ariane 5 is operational. During rocket launch, since the solid propellant generates high thrust, the sheer volume of the sound can damage the rocket. Hence a sound suppression system has been installed in the launch pad which will spray about 20 tonnes of water per second to dampen the effect of the sound during lift-off.

The second stage is a 4 meter, Liquid motor; L-110 containing 118 tonnes of liquid propellant with two improved Vikas engines generating 700 kilonewtons thrust each. These will burn for 200 seconds. During the flight as the thrust from the solid motor begins to tail off around 113 seconds, sensors on board will detect the decline in acceleration and subsequently ignite the L-110 and the two Vikas engines.  Before the two S-200 boosters separate and fall off, solid boosters and liquid Vikas engines work together for some time.  The core third stage is cryogenic stage containing LOX (Liquid Oxygen) and LH2 (Liquid Hydrogen) provide half the velocity required to put satellite into the orbit. While the solid motors and liquid stage completed ground tests and were ready for flight three years back, development of cryogenic engine is still in progress and will be ready by 2015.

Meanwhile for the experimental launch, the third stage is replaced by a passive cryo engine  will carry 3735 kg CARE (Crew- module Atmospheric Re Entry Experiment) Module, bed room sized, cup cake shaped, aluminium module intended to accommodate three crew members. The endeavour of the mission is to test the atmospheric phase of the flight and measure the thermal pressure. GSLV Mark III is more sensitive than the PSLV and the ability of rocket control systems to handle perturbations as it meanders through the dense environment without violating the vehicle’s structural capabilities will be monitored during the experimental flight.

This mission touted to be precursor for India’ manned space flight programme planned for 2020. After 325 seconds after liftoff, the crew module will separate from the rocket at an altitude of 126 km. It would make a re-entry into the earth’s atmosphere experiencing   gruelling 1600 degrees C temperature. It descent will be facilitated by three parachutes tested at Chandigarh and Sriharikota facilities. About 1280 seconds after launch, the crew will make a splash down in Bay of Bengal 600 km from Port Blair and will be recovered by Indian Coast guards. Though the crew will not carry any humans, recovered module will be tested for all the safety parameters.

GSLV can enhance the satellite launch capabilities of ISRO for GTO, LEO (Low Earth Orbits), polar and intermediate circular orbits. A sturdier GSLV would make India self reliant thereby it can emerge as the most lucrative competitor in the multibillion dollar satellite launch vehicle global market.

 

 

 

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New Horizon Mission’s Pluto Probe Wakes up from Hibernation

New Horizon Mission was commissioned in 2006 to study the objects of Kuiper belt region beyond the Neptune and Pluto-Charon, binary planet. Solar system has three classes of planets- the inner rocky or terrestrial planets (Earth, Mars, Mercury and Venus) the gas giants (Jupiter, Saturn, Uranus and Neptune) dominated by thick molecular hydrogen atmospheres and the ice dwarfs of the Kuiper belt that has solid surfaces with significant icy material (frozen water, nitrogen, carbon dioxide, methane or carbon monoxide). There are large numbers of ice dwarfs than the rocky and gas giants put together but no space craft has been sent to them. New Horizon Mission is set to fill that gap. The ice dwarfs are small planets whose growth stopped when they attained sizes of 200 to 2000 kilometres diameter. These are ancient relics from which giant planets have formed 4 billion years ago. Hence they have great deal to teach about planet formation. With this mission US has made history of sending space probes to all the planets of the solar system. Galvanised by success of Orion spacecraft NASA is very keen to work on this New Horizon Mission.

Launched from the Cape Canaveral, on Jan 19^th 2006 by Atlas V 551 rocket, the 8 year interplanetary cruise included a flyby of Jupiter in 2007. It crossed the orbits of Saturn in 2008, Uranus in 2011 and Neptune in August 2014. Following its encounter with Neptune it entered into a slumber to be woken up after a 99 day break on Dec 6^th 3am EST to gear up for six month Pluto encounter. It has cruised 3 billion miles (4.8 billion kilometres) and spent two-thirds of its journey in hibernation over the course of 18 separate hibernation periods ranging from 36 to 202 days in duration. The probe has been pushed into hibernation so often to reduce wear and tear and operation costs. Every few months the probe was awakened for a check up where by it would send weekly blips to the mission known as ‘green beacons’ to say that it’s not dead. Pluto’s encounter would start technically from Jan 15^th 2015 during which it will probe Pluto and its five moons (Charon, Nix, Hydra, Kerberos and Styx) for the next six months. After Pluto the mission plans to send the probe past two icy objects in the Kuiper belt, the ring of cosmic belt which lies beyond Neptune by 2018 or 2019 provided funds are sanctioned to the mission.

The $728 million mission has seven objects on board to study the geology and topography of Pluto and its largest moon Charon. To map the surface compositions and temperatures, study Pluto’s atmosphere and any undiscovered moons and rings in the dwarf planetary system. Pluto and Charon are together referred to as binary planets. The term is used to refer to any pair of worlds that are similar in mass. Pluto discovered in 1930 is classified by International Astronomical Union as a dwarf planet.

New Horizons mission is highly sophisticated and the smallest space probe ever sent into the Solar System. Great care and precision were exercised in selecting miniature components and instruments capabilities to fit in relatively smaller pay load. The instruments on board include-Alice, an Ultraviolet Spectrometer, LORRI, a camera; Ralph, a multi-spectral imager with five channels; LEISA, an infrared spectrometer; REX, an instrument which sends radio signals to Earth; Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) to monitor the ions escaping atmosphere of Pluto; Venetia Burney Student Dust Counter to gauge the distribution of size and particle density of ions and Solar Wind of Pluto the analyser of Solar Wind which is sensitive to particles of low energy. By July 14^th New Horizons will be nearest to Pluto’s surface, roughly  6200 miles away. Message from Earth takes four hours to reach the Pluto despite travelling at light speed. Since the mission is operating at four billion kilometres distance from Earth in deep space communication mode, transfer of data might be very slow. Sometimes communication may be impossible when it is focusing on certain points. Scientists expect silence for two weeks when it is too close to Pluto.

Following the wakeup of New Horizons Mission from slumber there is palpable excitement among scientists as this ambitious mission is going to unravel unprecedented information and images about Pluto.

 

 

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NASA’S Orion Spacecraft: a fore shadow for an ambitious Manned Mission to Mars

The highly anticipated Orion space mission was postponed by a day due to a volley of reasons. NASA had to postpone the launch scheduled for Dec 4^th after a boat entered the launch area, strong winds forced automatic aborts and the two valves of the liquid hydrogen chamber failed to close properly. On Dec 5^th, near perfect execution of all the stages of the Orion mission galvanised NASA’s future Mars exploration missions. Orion is NASA’s next-generation spacecraft built to carry human beings deeper into space with a goal of undertaking a manned mission to the red planet by 2030. To accomplish the task, Orion was built to scale higher speeds, to withstand the extreme temperatures and radiations of the inner space.

Orion was launched on a ULA Delta IV Heavy Rocket from Cape Canaveral, Florida. Its entire flight spanned for four and half hours. As it began to orbit around earth, its protective panels detached from the safety system known as the launch abort system following which engines in the upper section had fired. It lopped earth twice and reached an altitude of 5808 kilometres, 15 times higher than the International Space Station (ISS). One of the critical phases has been the journey through Van Allen belt a dense radiation zone. Scientists had apprehensions about this part of journey as radiations were believed to harm the guidance system of Orion, computers and other electronics on board and astronauts too. When Orion reached its highest point, the upper stage of rocket triggered separation to propel its return journey to earth. As Orion began to re-enter earth’s atmosphere, it encountered temperatures twice the burning lava, roughly 2200 Celsius. Space craft reached speeds of 32,000kmph during its re-entry. Finally a series of four giant parachutes tried to decelerate the craft and it splashed down into Pacific Ocean 400 miles west of La Paz, Mexico. The craft was designed to make touch down at a speed of 32kmph as higher speeds could disorient the crew inside. The capsule has been located by a drone. After its retrieval from water, it was been carried back to NASA for further analysis. The flight was meant to validate avionics, heat shielding mechanisms and parachutes.

Orion flew faster than any space craft designed so far since the Apollo moon programme. The capsule was designed to carry 6 astronauts into deep space. It 16 ft heat shield and the sophisticated service module are the ones which will be critically tested. NASA has also developed emergency abort function to save the astronauts in the event of any malfunction during the launch. The entire mission costed $370 million. The spectacular success of the Orion flight has boosted NASA, which is planning for an unmanned flight for 2018 and a manned mission or rather a flight along the moon’s orbit by 2020. It plans to send astronaut to an asteroid and Mars by 2030.

US once a space super power, had to end its Space Shuttle Program in 2011 following which it has been buying two seats in Russian Soyuz to fly to and from the ISS. To send spacecrafts to moon and beyond, NASA is developing Space Launch System (SLS), a rocket larger than Saturn Vs which took astronauts to moon in 1960’s. Orion had an instrument Bird (battery operated independent radiation detector) on board to monitor radiation while in space. This is a major health concern for humans undertaking as Mars voyage which will last for 9-12 months. Orion capsule bears a close resemblance to the Apollo craft that ferried astronauts to moon 40 years back. Though NASA’s future missions are not made public, it is certainly gearing for several ambitious programmes in near future.

 

 

 

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GSAT-16 Communication Satellite Launched Successfully

The communication satellite GSAT-16 weighing 3,181 kg was stationed into the Geosynchronous transfer orbit (GTO) by the European Launcher Ariane 5 VA 221 rocket from Kourou space station in French Guyana. The launch was delayed by two days due to   inclement weather conditions. GSAT’s 48 responders, 12 in C-band, 12 in extended C band and 24 in ku band would cover the entire country including the Andaman and Nicobar Islands. Co journer along GSAT is the US broad cast satellite DIRECTTV-14.

GSAT-16 is tipped to replace the INSAT-3E at 55degrees East longitude which was decommissioned prematurely in April this year. The satellite will augment and boost the communication potential of television, radio, internet, public and private cable operators. ISRO launched its previous communication satellite in January this year. The cost of launching the satellite and its construction was estimated to be 880 crore. This is the 63^rd successful launch of the Ariane 5 rocket. India’s work horse PSLV (Polar Satellite Launch Vehicles) can launch satellites weighing less than 1 tonne into polar orbits. Lack of reliable launcher, the GSLV’s (GEO synchronous launch vehicles) with cryogenic engines to launch heavier communication satellite to GTO has been a biggest handicap for ISRO so far. ISRO with the successful trial run for testing GSLV in January has broken this jinx. Due to severe crunch of rocket launchers capable of delivering 4 tonnes satellite to GTO, India had to shell huge amount of money to European countries for launching communication satellites.

In a flawless launch, the satellite has been initially places into the elliptical orbit at an elevation of 36,000km and it will be adjusted to a circular orbit by the ISRO’s Mission Control Facility (MCF). Two more course correction adjustments will be carried out by the MCF in Hassan. GSAT-16 with designated with 12 years of operational life is co-located with satellites GSAT-8, IRNSS-1A, IRNSS-1B is 18^th satellite launched by Ariane space for ISRO. With a total of 168 transponders in C-band, extended C band and Ku band from the INSAT and GSAT satellites, India’s telecommunication, television broadcasting, weather forecasting, disaster warning, search and rescue operations will be greatly enhanced. ISRO is now developing the GSLV Mk III capable to carrying communication satellites of INSAT-4 series weighing 4500-5000kg. The existing GSLV Mk I and II are capable to carrying INSAT-2 series of satellites weighing 2000-2500kg into GTO. If ISRO manages to develop the GSLV MK-III India can become self-reliant in launching communication satellites thus reducing our dependency on Ariane Space. Eventually ISRO can compete in the multimillion dollar global satellite launch market earning huge revenues for country too...

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Japan’s Ambitious Mission to an Asteroid

On December 3^rd Hayabusa-2 a follow up for the Hyabusa probe (which landed on an asteroid Itakowa in 2005) was successfully launched from the Tanegashima Space Centre in Japan on a HII A rocket will arrive at the asteroid 1999 JU3 in 2018. Hayabusa-2 will spend 18 months to study the asteroid before returning to earth by 2020. Recently the historical launching of the Rosetta’s Philae landing on to a Comet 67P has generated tremendous enthusiasm among the space researchers and science enthusiasts alike to collect all possible information about the origin of our planet.

Unlike the Philae lander, this Japanese probe during the course of the study intends to conduct an explosion on the asteroid to collect the samples and place four devices and a small lander (MASCOT) similar to Philae lander. MASCOT lander has four imaging and magnetic sensing devices- MicrOmega, MAG, CAM and MARA. It will jump only once to change its location. Hayabusa-2 will position itself 20 km from the surface of the asteroid. The four mission instruments include a small- carry on impactor (SCI) having a 2 kg copper lump or liner which will be dropped at a velocity of 2 km/sec  on the surface of the asteroid to make an artificial crater by explosion. Second, a Near Infra red spectrometer (NIRS3) will investigate mineral and water metamorphism with near infra red rays. Third, a Thermal infrared imager (TIR) will study the thermal and temperature inertia of asteroid by capturing images of thermal radiation. It will find the particle of soil and porosity of the mass of rock that influences the temperature. Fourth, Small rovers (MINERVA-II) will hop on the asteroid surface to conduct probes. They have weights called torquers inside and hopping of rovers is facilitated by swinging of these torquers.

Other major instruments on board are the- Electric Propulsion System (Ion Engine) used for changing the orbit during Hayabusa’s onward journey to asteroid and return trip to earth. It enables the completion of trip with one tenth of the power consumption against the chemical propellant, a Sampler mechanism will collect samples on the surface of asteroid with a catcher, Target Marker will descend on to the asteroid surface as artificial landmark prior to the landing. It is structured as bean bag so that it will not bounce on the surface when it is dropped from explorer and a Re entry capsule with a container with samples from asteroid and will enter earth’s surface at 12km/sec where it will be retrieved. The main aim of the mission is to send back sizeable amounts of asteroid samples to earth by 2020.

There are millions of asteroids, which are believed to be shattered remnants of planetesimals, bodies with young Sun’s solar nebula that failed to grow large enough to become planets. Asteroids are minor planets of the inner solar system and classified as objects of asteroid belt (exist between orbits of Mars and Jupiter), Jupiter Trojans (Co-orbital with Jupiter) and near-earth Asteroids (NEA). Based on spectral characteristics, asteroids are classified into C-type (carbon rich), S-type (stony) and M-type (metallic).

Asteroid 1999 JU3 has been selected as its reflectivity indicated presence of organic matter and water. Its study can provide valuable insights about origins of sea water and life on earth in addition to the mystery of earth’s formation. It is an Apollo Asteroid. It is one of the near earth asteroids (NEA) which comes close to earth’s orbit. Asteroid is 900 meters in size with rotation period of 7.6hours. While the asteroid Itakowa   explored by Hyabusa is S-type asteroid this is classified as C-type asteroid. Asteroids are believed to contain information about the origin of solar system and its later evolution. During the formation of earth most of the original materials have melted, consequently there is no way to understand the beginnings of earth. Whereas the celestial bodies like Asteroids and Comets are like time capsules which preserve the history of the place and era of birth within solar system. Exploration of these bodies yields treasured information about the how the solar system is born and how original materials of life on earth were created and evolved in space.

 

 

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New Theory On The Evolution of Eukaryotic Cell

 

The emergence of eukaryotic cell was the precursor that heralded the process of evolution.  A eukaryotic cell with its functional organelle, organised nucleus enveloped in a nuclear membrane with a well connected endoplasmic reticulum was a quantum leap from the primitive prokaryotic cells. It laid the basic foundations for multicellularity and development of independent organisms capable of adapting to new ecological niches. Prokaryotes are believed to be the predecessors for the development of a eukaryotic cell. Existing theories believe that protomitochondria entered the cell via phagocytosis. According to those theories, the invaginations of the plasma membrane and internalisation of the membranes led to formation of compartments, endoplasmic reticulum that is continuous and organised around the chromatin to form inner and outer nuclear membrane. Assumption has been that nucleus was formed within the boundaries of existing cell with unaltered plasma membrane and these theories collectively were referred to as outside-in models.  Other theories are the endo-symbiotic theory which hypothesised that origin of nucleus and mitochondria has been consequence of repeated phagocytosis and endo symbiosis. This necessitates the presence of three partners- host, nucleus and mitochondria. Another was Syntropic consortium model wherein simultaneous fusion of cytoplasm, nucleus and mitochondria was envisaged. Endospore model suggested that nucleus evolved when cell enclosed its sister after cell division. In all of these models nucleus was derived from the internalised plasma membrane.

As against the reigning theories, Baum and Baum proposed a new model wherein Archae generated extracellular protrusions which led to development of eukaryotic cell and that eukaryotic architecture was formed by the extrusions. As expounded by the outside-in model, Archae are not known to undergo the process of endocytosis or phagocytosis. The new theory of inside-out has convincingly enunciated step by step process in the development of eukaryotic cell wherein the nuclear membrane, the oldest part of the cell is equivalent to the ancestral prokaryotic cell. Under this outer nuclear membrane, plasma membrane and cytoplasm are derived from the external protrusions or blebs and endoplasmic reticulum represents the gaps between the blebs. The process usually occurs during an intimate mutualistic association between an Archael host cell and a α-proteobacteria (containing a proto-mitochondrion). Initially mitochondria are trapped by the ER and it slowly penetrates and makes way into the cytoplasm. Eukaryogenesis (the process of development of eukaryotic cell) is sealed off by the formation of continuous plasma membrane and closing off the ER to the exterior. In this model prokaryote is termed as eocyte having a single lipid bilayer membrane and a simple cell wall rich (S-layer) in N-glycosylated proteins, cytoskeleton homologs of actin and tubulin and a membrane manipulating protein ESCRTIII.

The new theory is empirical and experimental evidence nearly validates the theory, firstly Archae are known to form protrusions to increase their surface to volume ratio. Formation of protrusions is facilitated the S-layer proteins and the cytoskeleton while positive curvature of the protrusions are stabilised by proteins containing seven blade beta propeller domains homologous to the Coat  Protein (COP II) that form outer ring of nuclear pore. Accordingly, the outer membrane of the nuclear pore complex (NPC) will be a highly conserved portion and it is found that most eukaryotes have most stable proteins in NPC. Recent data suggest that mitochondria are closely related to proteo-bacteria precisely to the Rickettsiales group of intracellular parasites of eukaryotes. These are known to enter the food-vacoule and then enter cytoplasm proper by lysing the vacuole. Since the external protrusions swelled beyond S-layer, osmoregulation is another feature which has to be accounted. It is known that Archael cells thrive in an environment containing high external osmolytes wherein the chances of bursting of cell due to thinning or loss of S-layer are negligible. Moreover, the expansion of the blebs pressed against each other generate a continuous network against each other is akin to the lumen of the nuclear envelope and ER of highly developed eukaryotes.

Three different kinds of evidence support the inside-out theory elucidated by authors. The first set of evidence support the characteristic features of the eukaryotes like existence of nuclear membrane without any internal membrane bound organelles, presence of double nuclear membrane with periplasmic space continuous with ER and why N-glycosylation is initiated in the nuclear envelope is explained parsimoniously by this model. The second set of evidence explains the unusual or quirky features of eukaryotes like the close connections between the ER and mitochondria and their prominent roles in lipid synthesis and provides logical explanation for the presence of phosphoinositides in the nucleus and their role in mRNA processing are convincingly detailed by the inside-out model. The third set of evidence draws parallels between the phylogenetic analyses of eukaryotic gene families. Phyogenetic analyses of the Ras GTPases superfamily propounds that secretion and exocytosis evolved before endocytosis. The inside-out clearly predicts similar phenomenon. Evidence identify that α-proteo-bacteria, (protomitochondrion) is a source of eukaryotic lipid biosynthesis and transport genes. This compelling evidence offers a plausible historical narrative for the origin of the Eukaryotes.

Evolutionary theories envisage the process of development that had occurred billions of years ago. Though the events are not testable, these hypotheses help us to understand and analyse the slow and steady process of development and the underlying biology.