One Step Beyond...
• Nathan Davies

Space has, since long before Gene Roddenberry coined the phrase for Star Trek, been thought of as the ‘final frontier’. It represents the ultimate practical limits to which mankind can aspire and expand. It is a breach into the unknown, and more importantly, it is a place that has remained beyond the reach of the vast majority. However, standing at the dawn of a new millennium – in the year 2001 no less – all of that has slowly begun to change.

The most prolific of these changes is now not even a thing of the future, but rather something of a milestone in the history of space flight. On the 28th April this year, Dennis Tito became the first man to leave the earth aboard a spacecraft in a non-operational capacity. Having reportedly paid a sum of $20 million (approximately £14 million) to the Russian Space Agency for the privilege, the Californian millionaire became the first ever ‘space tourist’. At least from this planet.

Although prohibitively expensive for most of us at the moment, Tito’s ‘mission’ has set the rather controversial precedent for more extra-terrestrial excursions. Another mission is set for as early as October, should all the nations involved with the international space station consent to having another paying guest stop by. There are also rumours that another wealthy would-be astronaut has signed up with Space Adventures, the American company that arranged for Tito’s flight, but whoever it is will have to wait. Not only is it imperative that the tourists spend a minimum of six months of intensive astronaut/cosmonaut training after completing a thorough medical examination, and learn Russian, but there is only one available seat in each cramped Soyuz capsule used in these supply missions. Even if you have the money, getting into space is still not easy, but that need not always be the case. As scientists and engineers the world over are designing new ways to get us up there.

One such revolutionary design is the Alchemist system being developed by a team from Andrews Space and Technology in California. Instead of burning petro-chemical rocket fuels in an extended, explosive ‘blast-off’, Alchemist would involve a two-stage take-off utilising at least three forms of engine. Although it sounds a lot more complicated than the existing shuttle it is actually lighter, safer (potentially cheaper) and more efficient design that is even capable of departing from a regular commercial airport.

The secret is in using liquid oxygen as a propellant. There’s lots of it (albeit in gas rather than liquid form) and it’s free, but the biggest advantage is that it does not have to be loaded aboard on the ground. Instead, Alchemist harvests oxygen by flying around in the atmosphere for a few hours, storing and condensing it into liquid form aboard a carrier plane the size of a regular Boeing 777. When the tanks are full the liquid oxygen is mixed with liquid hydrogen already on-board and used to blast off for the upper reaches of the atmosphere. There the orbiter, a smaller vehicle sat atop the carrier, detaches and safely escapes into, well, orbit.

Because the liquid oxygen is added in-flight, the plane’s total weight at take off would be reduced by roughly a half allowing it to fly in the fashion of a regular plane. Also, with the fuel isolated in two parts, the risk of explosion is greatly reduced, making it possible to take-off from conventional airports, and by moving the bulk of the engines and fuel to a carrier there would be more space in the orbiter for cargo, or passengers. While not actually developed with ‘space tourism’ in mind, this proposed replacement for the shuttle could yet become the astronautical equivalent of the chartered flight. Chris Hoeft, a spokesman for Andrews, claims that should Alchemist or a similar system be picked up, the cost for space flight could drop low enough to make space tourism a common occurrence in around 15 to 20 years.

Taking a longer-term view of near-space travel, there are some even more outlandish ideas, the theories and models for many of which have already been proven. Most notable among these is the ‘space elevator’ concept that was the centrepiece for Arthur C. Clarke’s novel The Fountains of Paradise; a form of cable-car that would ride a tapered vertical wire between Earth and a space station in geo-synchronous orbit. Most the science and technology for this strange but apparently feasible mode of transport is already in place or in development, all that really stands in the way of practical tests is producing a form of carbon (nanotubes, or perhaps their successors) that could function as the wire itself. This being the case, don’t expect to take the express lift into orbit for another hundred years or so. We should not, however, have to wait that long for new missions (both manned and robotic) that will go a lot further afield.

The Space Elevator -- arriving sooner than we think? Image courtesy NASA http://flightprojects.msfc.nasa.gov/fd02_elev.html

One such project involves another favourite of science fiction, the solar sail; a device developed to catch photons emanating from the sun and therefore ride the solar wind. In the past this form of space travel has always been considered a lost cause because, despite being able to accelerate to incredible speeds, it takes time. Too long for what most space faring agencies want or need, even if given a starting push with microwaves or laser beams. But that was the past. Although we aren’t yet at a stage where technology has advanced to allow for smaller sails fast enough to get a manned mission to Mars in an acceptable time, advances in parachute and airship materials are putting the solar sail back in the (space) race. In fact, a team being lead by Nersi Razavi of the Airship Industries Group is already putting the finishing touches on their first test sail and plan to launch it before the end of 2002. Measuring only 400 metres the sail is likely to take a whole month to travel from its cargo rocket to a pre-designated spot in safe orbit, but it will allow Razavi’s team (backed by both the combined European Space Agency and the German Space Agency) to test the deployment system, and see how bright it will be from Earth.

If all goes well a larger sail (the dimensions of which will be determined by next years test) will be launched by 2005. This could potentially pave the way for more missions involving the technology where size or weight is an issue but where time might not be, such as, investigating asteroids, unmanned missions to Mars and even quick trips to Pluto. We could even rig a sail to accelerate out beyond the edges of our solar system. Razavi also hopes that the ‘Star of Tolerance’, as he is calling the project, will become a symbol of peace and co-operation that we will all be able to see from Earth, as well as inspire races and regattas between the Earth and the moon.

So, more people are going into space and exploding the elitist myth surrounding the so-called ‘final frontier’. We are now able to explore space more fully, push back that frontier to the very limits of our solar system and make faster trips around it. But what are we going to do with all this space? The same thing that we have done with space here on Earth; move in.

Colonising isn’t as far-fetched as it sounds; after all, we have already got a foothold in space in the form of the international space station. Going to other planets, however, has always been a problem. It’s expensive and wasteful and our only success, the Moon, isn’t even another planet, but Mars could finally be within our reach. According to astronaut/physicist Franklin Ramon Chang-Diaz, a manned team to the red planet could leave as early as 2018 and might only take 115 days in-flight (approximately half the time of conventional estimates). The secret to this early launch and the short flight time is Vasimir, a Variable Specific Impulse Magnetoplasma Rocket.

Instead of using standard rocket fuels, Vasimir will be propelled by a controlled burst of ionised gas (plasma) that will burn for the whole journey at about 1 million degrees centigrade. Allowing the engine to fire continuously means that the ship can continue to accelerate, thereby making the journey a lot quicker. The problem is burning plasma, the stuff that the sun is made of, at that temperature is that it would vaporise all of the engine components. To get around this, Vasimir will use a series of magnetic fields to contain it and manipulate it through the various converters and out of the exhaust. Chang-Diaz’s team already has a working prototype here on Earth, and is hoping to launch a test flight of a more powerful version within the next five years. After that it may just be a case of increasing the power supply and building a version big enough to contain it. With the next optimum launch window in less than 20 years time, Mars could be just around the corner.

And after Mars, who knows? Once the technologies are in place the possibilities are almost endless, at least in theory. Faster, tougher, smarter ships are only half the battle. Mankind still has to deal with the rigours of space, and its constraints. You can’t change your room because it’s not to your liking in orbit, and there are serious implications for ones health if you spend too long in zero or micro-gravity. But these things will undoubtedly be solved in time, we will just have to be patient. After all, what's the rush? Space may no longer be the ‘final’ frontier, but its a big one with plenty of, well, space, to go around, and no one has tried to jump our claims. Yet.

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