Humans are very eagerly looking at the spacefrom the ancient time itself. Humans always want to explore to the outer spaceand find a place a where they can live.
Earth is the only planet that we knowwhich had provided the sufficientcondition for the existence of life. In our universe there are billions ofgalaxies and in each of them there where billions of planets are there. So thepossibility of existence of life on any of these planets is huge. But toexplore to another world we need to travel a huge distance.
Our nearest star isAlpha Centauri which is located at a distance of 4.4 light years from earth.Using our current propulsion technique we have achieved a maximum speed of170m/s for the Juno spacecraft. But using this speed exploration to another starwill take millions of years. So, the speed of the craft needs to be increased.
According to Dr. Robert Frisbee of NASA’s Jet Propulsion Laboratory, the fueltakes up almost 2/3rd of the craft’s mass and is stopping us from reachinghigher speeds. Inthe nearly 60 years of spaceflight we have achieved wonderful feats ofexploration that have shown the incredible spirit of the human drive to exploreand understand our universe. Yet in those 60 years we have just left our solarsystem with the Voyager 1 spacecraft launched in 1977 finally leaving the solarsystem after 37 years of flight at a speed of 17 km/s or less than 0.006% thespeed of light.
According to our current propulsion technology we are dependingon rockets which produces thrust by chemical reaction. Ifwe can find other alternatives for fuel, science fiction levels of speeds canbe attained. Utilization of the energy of light (Photonic propulsion)strangely proposes a good solution as it allows very little or no fuel to becarried along with the spacecraft. Photons do not have mass, but they haveenergy and momentum.
When they get reflected off an object, that momentum istransferred into a little push (thrust). The thrust depends only on power andnot wavelength. Clearly, these spacecrafts needs to be very small in size andcannot be used for manned missions.