Ion Propulsion

Technically not upcoming, ion propulsion is already a reality. Since it propels a spacecraft one particle at a time (as opposed to chemical propulsion, which explodes, generally, out the back), this propellant is hugely efficient.

The trick is what’s known to physicists as “specific impulse”. When a chemically propelled vehicle propels, it causes an explosion out the back, pushing the object forward. After exiting the vehicle however, the explosion immediately spreads in all directions, meaning that much of the energy of the explosion is lost on direction other than the one the spacecraft wishes to move.

Ion propulsion takes a long time to build speed but is so efficient that NASA’s Dawn spacecraft, being an ion propelled machine, is the first to be able to orbit multiple things in the solar system.

With ion propellant, a spacecraft may be able to even generate enough speed to allow for interstellar space exploration (meaning it could enable us to leave the Solar System). Though speculative, the possibility is undeniable.Read & learn:http://www.nasa.gov/centers/glenn/technology/Ion_Propulsion1.html

Reference:http://dawn.jpl.nasa.gov/technology/

Image: Ion thruster operation via NASA