NASA's Kepler Telescope has sighted thousands of exoplanets – worlds outside our solar system – this year alone. These mysterious distant worlds are fascinating, with some offering tempting hopes to find alien life or habitable planets for future colonization. However, the ambitions to explore these planets are being thwarted because of the enormous distances involved. But those dreams of exploring interstellar space will one day be made if NASA's Princeton Satellite Systems builds its nuclear fusion space engine – which some experts believe is only a decade away.
Nuclear fusion is when you take two atoms and melt them to produce energy.
Our payload would be between 500-1,000 kg or more, which could help travel in the internal or external solar system
The process feeds the Sun, which can be understood as a large fusion reactor.
Replicating the fusion to harness its power unimaginable long ago is considered a dream, but Dr. Michael Paluszek, president of Princeton Satellite Systems, a NASA contractor, is confident that its direct fusion unit will soon supply interstellar space travel.
He told Express.co.uk: "The sun uses gravity to trigger fusion by compressing the atoms together.
"We use magnetic fields to provide confinement and we heat them externally with radiofrequency waves.
"And then you get the fusion, which can be used as an additional propellant, which is introduced into the chamber and exits a nozzle to produce momentum."
Nuclear fusion unit: a nuclear fusion engine will one day help us to explore interstellar space
Nuclear fusion unit: the Sun can be understood as a giant fusion reactor
It has been estimated that this fusion technology will reduce the travel time of a seven-year-old Saturn spacecraft to just two.
And a nine-year voyage to Pluto would take only five years, say researchers.
The direct fusion unit will be able to carry loads between 500-1,000 kg or more, which could help travel in the internal or external solar system.
Stephanie Thomas, vice president of the company, adds that the unit of direct fusion is not only useful for its speed.
She said: "Our cargo would be between 500-1,000 kg or more, which could help travel in the internal or external solar system.
"And the power available to these loads would be hundreds of kilowatts.
"You can do many different things with your cargo, including mining and drilling for asteroids.
"The nuclear fusion system can also be used to generate energy on the moon or on Mars.
"So it's not just where you can go, it's different, it's the mission you're bringing with you that is different."
Fusion technology could be used here on Earth in remote areas and in emergencies and the direct fusion unit could be able to generate 10 megawatts of power.
Nuclear fusion: Replicating the merger to harness its unimaginable power has been considered a dream
Nuclear power merger: a nine-year voyage to Pluto would take only five years
Nuclear fusion offers tempting benefits to other next-generation technologies being prepared to fuel deep space exploration such as solar sails and nuclear fission, Paluszek told Express.co.uk.
He said: "We know that solar sails work because I used to work on communication satellites and we had to deal with the solar pressure pushing our satellite around.
"Solar sails are a very significant technology, but they will only really be useful in the internal solar system.
"So if you want to travel to Neptune or Pluto, solar sails will not be very useful because you can not slow down.
"Another big disadvantage is building big enough big candles is really hard.
Merger of nuclear power: a journey to Saturn would be cut from seven years to just two
"And the payload you can put on a solar sail would have to be very small, between 50 and 100 kg."
One method to help spacecraft slow down is the "huge laser", but the technology is still theoretical.
Dr. Paluszek said: "The idea is to build a laser with a large aperture and the aperture has to be large because the diffraction limits are based on the aperture size and the smaller the aperture, the larger the aperture.
"So in order to get enough energy to get to Pluto, you would need a gap large enough that would allow the spacecraft to slow down."
Nuclear fission plants that generate electricity are other technologies of interest.
But there have been several attempts by NASA to build fission nuclear power plants capable of flying in space, but without much success.
Dr. Paluszek explained: "The problem you have with fission is that you have to fly with uranium or plutonium, which has safety problems.
"And a related issue is that a rocket would have to carry a lot of armor, which would be quite heavy.
"That means your power / weight ratio to travel within the solar system is actually very low – worse than using a solar sail."