The Future of Space Travel

By Kaitlyn Kralick

What Is The Most Traveled Spacecraft of Today?

• Voyager 1 is our most travelled spacecraft to date, clocking up 12 billion km during its incredible journey to the edge of our Solar System. However, this long-haul trip has taken over 30 years to complete. What's more, even at speeds of over 35,000 mph, Voyager will take a further 20,000 years to reach the middle of the Oort Cloud, the hazy swarm of comets that surrounds the Solar System. Proxima Centauri, our nearest star, is twice this distance again. Clearly, if we want to explore further than our celestial doorstep, we must find new modes of space travel.

Some future technology for space of the

future…

Solar Sails…• Dreamt up at the beginning of last century,

solar sails are now moving a step closer to reality, as one of the most feasible ways of traveling into deep space. They are lightweight panels made from reflective material that act like the sails of a boat. Rather than using wind, the sails are actually propelled by light. Unbelievable as it may seem, the stream of light particles (called photons) emitted from the Sun are strong enough to push a mini-spacecraft right out of the Solar System and beyond into interstellar space.

Pros and Cons Of Solar Sails

• Initial acceleration is low, meaning that solar sails could only carry robotic probes. However, because they are so lightweight and have a continuous source of energy, they could eventually accelerate to speeds of around 90 km per second. At that speed they could travel from London to New York in just over a minute; that's over 10 times faster than the Space Shuttle. And unlike current spacecraft, they are also reusable and do not require costly refuelling for new missions.

Ion Engines

• Instead of burning chemical fuels, ion engines are electrically charged and work by ejecting positive ions from the back of the rocket, propelling the spacecraft forwards. The thrust is tiny; in fact it's comparable to the pressure of a piece of paper on your hand. However, the ion engine is extremely efficient, allowing the fuel to last far longer than in conventional rockets, making these spacecraft lighter and cheaper to launch.

What’s So Great About Ion Engines?

• Future missions for the ion engine could include comet sample returns, observations of the rings of Saturn and a landing on Jupiter's moon, Europa. Their light mass means that ion powered spacecraft can gradually accelerate to extremely high speeds. Conventional rockets would take nine years just to catch the comet, let alone return with the precious bounty.

Nuclear Power

• One of the most feasible, yet controversial, methods of powering spacecraft on long journeys is by using nuclear energy. Our current chemical engines produce relatively little power. They have to make use of planetary alignments, or 'launch windows', to provide an extra gravitational slingshot effect, helping to catapult them further out into space. Nuclear rockets would be more powerful and wouldn't need to take advantage of these chance planetary patterns.

Pros and Cons of Nuclear Power

• Rockets run by nuclear fission are more fuel efficient, and so much lighter, than chemical rockets. This means that, nuclear spaceships could travel twice as fast as our current chemical spacecraft. A nuclear powered craft could reach Saturn in as little a three years, rather than the current journey time of seven years. What's more, because the fuel lasts longer, the spacecraft would still have enough energy left to tour the Solar System for up to 15 years.

• The main problem with fission engines is the controversy over nuclear waste. The Earth's environment could be protected by launching these spacecraft with conventional chemical rockets. Only when the spaceship was well away from the Earth would the nuclear reactors fire up, ensuring that the radioactive waste wouldn't find its way back home. However, the production of radioactive waste would pose a problem for sending manned missions on nuclear spacecraft rather than robotic probes.

Antimatter Spacecraft

• In 1928, the physicist Paul Dirac suggested that particles might have alter egos called antiparticles, having the same mass but opposite charges. If these two particles were to meet, there would literally be fireworks. All of their mass would be converted into energy, according to Einstein's famous equation, E=mc2. This makes antimatter the most efficient fuel possible; just a small amount the size of an aspirin could power a spacecraft over distances of hundreds of light years. The Moon could be minutes away and Mars a matter of days.

What’s The Matter with Antimatter?

• The problem is that currently it takes more energy to make antimatter than it produces. Due to this, only 10 billionths of a gram is produced globally per year. This paltry amount isn't even enough to heat a cup of coffee, let alone travel to another planet. In addition to this, there's also the tricky problem of storage; how do you contain antimatter when it explodes as soon as it comes in contact with matter?

Flying Saucers

• Since the age of the 1950s B-movies, flying saucers have been the vehicle of choice for any discerning alien. Looking like a cross between a metal hubcap and a glow-in-the-dark frisbee, these strange spacecraft have fascinated us for decades. Whether you accept Area 51 or reject the Roswell Incident, there's still a chance you may see a flying saucer in the not too distant future. However, rather than carrying extra-terrestrials from other planets, the saucer could be transporting you round the Earth or even to the Moon.

Drawbacks

• Currently, the craft is very small and noisy, but NASA has drawn up a design plan for a 20m microwave-powered saucer, carrying up to 12 people to the Moon in just six hours. The power supply would be harvested by solar panels, housed on a lunar orbiting power station. After converting this solar energy into microwaves, these waves would be beamed straight to the Lightcraft to power its lunar trip. Once the saucer nears its destination, the crew would have to slow the ship down by steering through a series of ring-shaped electromagnets on the Moon, before touching down on the lunar surface.

Space Elevators

• Space tethers are strong, light cables that have been used since the 1960s to couple spacecraft together, or to transfer fuel between vehicles. More recently, scientists at NASA have set their sights even higher, envisioning a 40,000 km-high elevator extending into space.

Whats good about Space Elevators?

• Space elevators could slash the cost of jetting off into space. Currently sending a tourist (including baggage) on the Shuttle costs around £60,000. A trip on the space elevator could cost a mere £150.

Bibliography

• http://www.bbc.co.uk/science/space/exploration/futurespaceflight/spaceelevators.shtml