Now- a -days our technology has improved tremendously particularly in the field of astronomy. Recently several government and private sectors invested lot of bucks in the space race who will be the first one to colonize the red planet Mars.
In the beginning of space age, countries spend a huge amount of money for every rocket launch since 1900’s. Liquid and chemical propellants causes the price of rockets to soar up. But, now the cost of rockets has been dramatically reduced to minimum by reusable rockets. ISRO and Space X have successfully reduced the cost of Rockets. Whatever the cost maybe, every rockets we use is still chemical propelled which is not cost efficient.
So, we need to design an alternate way to space travel unlike chemical propelled rockets, scientist’s developed a new rocket engine known as Ion thruster or propulsion engine which is more efficient in space travel and cost. This new ion thruster could ferry supplies to Mars using 100 million times less fuel.
A chemical rocket tops out at around five kilometers per second (1.86 miles/sec), while a Ion or Hall thruster can reach speeds of up to 40 kilometers per second (25 miles/sec).
Ion thruster history
NASA first began researching ion propulsion in the 1950’s. In 1998, ion propulsion was successfully used as the main propulsion system on a spacecraft, powering the Deep Space 1 (DS1) on its mission to the asteroid 9969 Braille and Comet Borrelly. DS1 was designed not only to visit an asteroid and a comet, but to test twelve advanced, high-risk technologies, chief among them the ion propulsion system itself.
How Ion Drive Works
An ion thruster or ion drive is a form of electric propulsion used for spacecraft propulsion. It creates thrust by accelerating ions with electricity.
Ion drives strength lies in continuing to generate thrust over time. This means that they can achieve very high top speeds. Ion thrusters can propel spacecraft to speeds over 320,000 kp/h (200,000 mph), but they must be in operation for a long time to achieve that speed.
An ion is an atom or a molecule that has either lost or gained an electron, and therefore has an electrical charge. So ionization is the process of giving a charge to an atom or a molecule, by adding or removing electrons. Once charged, an ion will want to move in relation to a magnetic field. That’s at the heart of ion drives. But certain atoms are better suited for this. NASA’s ion drives typically use xenon, an inert gas, because there’s no risk of explosion.
In an ion drive, the xenon isn’t a fuel. It isn’t combusted, and it has no inherent properties that make it useful as a fuel. The energy source for an ion drive has to come from somewhere else. This source can be electricity from solar cells, or electricity generated from decay heat from a nuclear material.
Ions are created by bombarding the xenon gas with high energy electrons. Once charged, these ions are drawn through a pair of electrostatic grids—called lenses—by their charges, and are expelled out of the chamber, producing thrust. This discharge is called the ion beam, and it is again injected with electrons, to neutralize its charge.
Unlike a traditional chemical rocket, where it’s thrust is limited by how much fuel it can carry and burn, the thrust generated by an ion drive is only limited by the strength of its electrical source.
The amount of propellant a craft can carry, in this case xenon, is a secondary concern. NASA’s Dawn spacecraft used only 10 ounces of xenon propellant—that’s less than a soda can—for 27 hours of operation.
In theory, there is no limit to the strength of the electrical source powering the drive, and work is being done to develop even more powerful ion thrusters than we currently have.
In 2012, NASA’s Evolutionary Xenon Thruster (NEXT) operated at 7000w for over 43,000 hours, in comparison to the ion drive on DS1 that used only 2100w. NEXT, and designs that will surpass it in the future, will allow spacecraft to go on extended missions to multiple asteroids, comets, the outer planets, and their moons.
Missions using ion propulsion include NASA’s Dawn mission, the Japanese Hayabusa mission to asteroid 25143 Itokawa, and the upcoming ESA missions Bepicolombo, which will head to Mercury in 2017, and LISA Pathfinder, which will study low frequency gravitational waves.
NASA’s New X3 Ion Thruster Breaks Record
NASA’s new X3 thruster, which is being developed by researchers at the University of Michigan in collaboration with the agency and the US Air Force, has broken records in recent test. It’s hoped that the technology could be used to ferry humans to Mars.
The X3 is a type of Hall thruster, a design that uses a stream of ions to propel a spacecraft. Plasma is expelled to generate thrust, producing far greater speeds than are possible with chemical propulsion rockets, according to NASA.
A chemical rocket tops out at around five kilometers per second (1.86 miles/sec), while a Hall thruster can reach speeds of up to 40 kilometers per second (25 miles/sec). This kind of increase is particularly relevant to long-distance space travel, like a prospective voyage to Mars. In fact, project team leaders project that ion propulsion technology such as this could take humans to the Red Planet within the next 20 years.
NASA’s X3 thruster on action:
Recent tests demonstrated that the X3 thruster can operate at over 100kW of power, generating 5.4 Newtons of thrust — the highest of any ionic plasma thruster to date. It also broke records for maximum power output and operating current.
In 2018, the team will continue to put the X3 through its paces with a test that will see it run continuously for 100 hours. A shielding system is also being developed that would prevent plasma from damaging the walls of the thruster, allowing it to operate for even longer, perhaps even several years at a time.