What Next For Space Travel?

What Are the Options for Future Space Travel?

The human race has long looked up to the stars in search of inspiration, enlightenment or excitement. And, in the 20th century, we made huge strides out into the Great Beyond of space. The first satellites were launched in the 1950s; then came the Apollo 11 moon landing in 1969; and then the start of the International Space Station in 1998. Today, our sights are set further still, and our ambitions are even higher.

Given the growing concerns over global warming and climate change, it’s perhaps easy to see why NASA, SpaceX, Boeing and various others are aiming to escape our atmosphere, to jet off to someplace else. Missions to Mars and commercial space-flights finally seem to be a near-future reality. But, exactly how is the technology progressing? And how must it evolve to achieve the starry dreams of mankind?

The biggest (and probably most obvious) hurdle we need to overcome is the time it takes to actually get anywhere in space. You can reach the moon within a week, but travelling to Mars takes months. So, shortening the cosmic commute is something we desperately need to accomplish. With this in mind, the chemical rockets of old are outdated and ineffective – requiring up to ten-to-fifteen times their own weight in fuel just to enter into Earth’s orbit. In general, there’s a dire need for an updated and reliable propulsion system, achieving more speed on less fuel – or else creating fuel on the go. This would also allow us to ditch ‘launch windows’, which currently dictate when we should (and shouldn’t) jet off to certain places. With Mars, the current launch window only comes around every two years, or so – when our orbits best align. Remove these windows, though, and we could be launching manned rockets or supply ships weekly, daily, or even hourly.

Solar sails are one of the more eye-catching options for actually achieving power. And they work pretty much as their name would suggest. They are enormous sails made of special mirrors, which allow ships to navigate using solar winds. And, as outlandish as it sounds, they’ve already been implemented and proven to work on Japan’s IKAROS probe – which flew by Venus in 2010. Solar sailing does have some downsides, though, namely that, as the craft gets further from the sun, it’s power decreases. If the end goal is to bust out of our Solar System entirely, then solar sails can only take us so far.

Nuclear pulse propulsion is another option, but also a much more destructive method of creating thrust. Detonating nuclear devices in space has been banned under the Partial Nuclear Test Ban Treaty since 1963, but advocates still argue that a spacecraft which moves by effectively dropping nuclear bombs behind it (and riding the force of those explosions) could travel as fast as 12% the speed of light. Clearly, though, this method is not without serious, serious risk. Filling a spacecraft with nuclear warheads obviously adds untold danger to any mission… but, even if the idea was safely realised, the g-force it’d create could kill anybody on board.

For a ship with significantly lower fuel demands, nuclear fusion engines and ion thrusters are almost certainly the way to go. Both have relatively low fuel requirements, but can power a ship over long distances with relatively little thrust. This means that, while they’re nowhere near as fast as nuclear pulse propulsion techniques, they are much safer. The technology behind fusion engines is still in development, but NASA has been experimenting with ion thrusters for years. The Deep Space 1 probe – launched in 1998 as part of the Agency’s “New Millennium Program” – used a gas ion engine for its journey. And, because this system is electrically powered, there’s no need to carry tons of fuel.

Once you’re off the ground and into orbit, solar energy is probably the most obvious way to generate power in outer space – where solar panels could be even more efficient, thanks to the lack of atmosphere (and the possible closer proximity of the sun). However, with solar energy comes solar radiation, which could damage ships – especially if they’re exposed to it over a long period of time.

Elsewhere, NASA are also developing new types of batteries for a future mission to Europa – one of Jupiter’s many moons. These super-powerful packs are able to work in extreme temperatures and radioactive conditions. Finally, there are Radioisotope Thermoelectric Generators, or RTGs, which use decaying plutonium to create heat and power that can reportedly last for decades. Again, RTGs do have their fans, but their use raises similar concerns to those surrounding nuclear pulse propulsion – namely that an RTG could prove a deadly cargo if it became damaged in any way.

So, say the space experts develop an ultra-efficient propulsion system, and a sure-fire way of fuelling the ship: What then? Having the ability to cover greater distances in shorter times (and at quicker speeds) would likely uncover all new problems.

Even with Mars, our nearest planetary neighbour, there are significant communication delays between it and the all-important mission control, back here on Earth. Currently, at its lowest, the time gap between sending and receiving radio signals is around three minutes – a fairly manageable inconvenience, unless there’s an especially fast-moving emergency. But, that delay can climb towards 24 minutes – depending on conditions. Given that these gaps will only widen when we try to journey elsewhere, it’s an area for improvement.

Some of the most creative solutions include building a large, space-based version of the internet; using the sun to boost our standard transmissions; building an enormous array of satellites throughout the Solar System; or employing “neutrinophones” – devices which have the distinct disadvantage of being largely fictional (at this point in time).

There is, of course, one sci-fi concept which, if turned into a reality, would sidestep almost all communication issues; teleportation. In 2017, the first ever teleportation of a particle from Earth into orbit was successfully carried out, so there has been some genuine progress made. True, we humans would definitely die should our atoms be somehow broken down and relocated, but if – in the far future – teleporting was a routine procedure, then we’d only ever need to traditionally ‘travel’ to other planets in order to build teleporters there. After that, we could beam to and from Earth in the blink of an eye... But, we’ve clearly still got a long way to go on that one.

One final problem, that we definitely can seek to solve, even here on plain ol’ planet Earth, is the physical preparedness of the people manning the ships; the astronauts of the future. NASA, and other space agencies, have already held various investigations, looking into the effects of long-term isolation on individual travellers, as well as the group dynamics within a small team. Any long-haul astronaut would likely be set a strict routine, designed to benefit their physical and mental health, combatting potential muscle wastage, sickness or loneliness. That said, right now the longest continuous stay in space is just 437 days – so it’s highly likely that the first long-distance traveller will encounter some unexpected health issues. There have already been steps made toward lessening the risk, though, with the development of sci-fi-style bio-monitor watches – which work like the ever-popular fitness trackers, but carry lots more information.

Of course, AI in general is sure to play a central role in any future space mission. Quite apart from the wearable tech that astronauts will no doubt rely on, artificial intelligence in the form of onboard robots will be (and already is) indispensable. Capable of monitoring systems and people, an advanced supercomputer could also solve the communication issues – because it would cater for every possible scenario, therefore lessening the need for a traditional ‘mission control’. Even today, we send probes and rovers to planets before ourselves, and we utilise robots on board the ISS to carry out tasks we couldn’t otherwise do. When it comes to space, AI is all about risk reduction – whether we’re wearing it around our wrists, or speaking to it via a screen.

All of which just leaves one final question; Where are we going to go? With various corporations currently engaged in a race to put people on Mars, it’s easy to forget that there are other places we could explore eventually – or even first. Some say it’d be wisest to test-run an enclosed colony a little closer to home before heading to the Red planet, by setting up on the Moon, instead. But others are already looking further afield, toward the various moons of Jupiter and Saturn – including Io and Titan – or even at Venus, our next-closest planet after Mars.

Clearly, the technology still has a long way to advance before such far-flung dreams can even be partly satisfied, but our brightest minds are definitely determined to make some mighty inroads into outer space. Next generation spaceships will launch unlike anything we’ve ever seen, travel further on less fuel, and offer an all-encompassing, ‘out of this world’ experience to anyone fortunate enough to fly in them. Whether it’s Mars, the Moon, or thousands of miles in another direction entirely, we’re making machines to take us there.