Space the Final Frontier, these are voyages of the blah blah blah...even if you hate science fiction at some point you will have probably heard those immortal lines!¹ However as its continuing popularity shows we love Star Trek and the idea of travelling to the stars and meeting distant alien cultures. Yet it all seems just a distant fantasy, most of us believe we will never see such flights of fantasy and probably neither will our grandchildren but in reality might we? Dr. Charles Pellegrino seems to think so. Pellegrino is a fascinating man, a scientist who has written books on subject ranging from Pompeii and Atlantis to the Sinking of the Titanic.² Working with scientists Jim Powell, Hiroshi Takahashi and vitally Pierre Noyes, Pellegrino has designed a space ship that he believes could have mankind leaving earth and visiting the stars by the year 2070.

Why go to the Effort?

The chance of there being life elsewhere in space is statistically quite probable and an equation known as the Drake Equation was created in 1961 to calculate the odds. If you just look at these figures for example you can see the likelihood of there being extraterrestrial life somewhere,

Say that only 0.01% of stars in our galaxy contain a planet with similar conditions to earth. There are somewhere between 3 to 100 billion stars in our galaxy so using these figures we have some 30,000 million earth like planets in our galaxy alone! Now say that life will only appear on 0.001% of these earth like planets, this means there could still be some 3 million planets with life evolving on it...in our galaxy alone! So the odds are good so far now add in this fact there are an estimated 600 billion stars in the nearest galaxy to our own, Andromeda, and it becomes even more likely. Finally factor in the estimated 300 billion galaxies in the visible universe. The bare statistics mean we are probably not alone in the universe!

Einstein’s famous theory means that we are unable to travel faster than the speed of light, in fact it would actually be impossible for an object of with 'normal' mass to achieve the speed of light so until we discover the real version of the Warp Drive used in science fiction we have to play within the confines of real physics. However that doesn’t mean we cannot travel at unbelievably high speeds which are still below light speed. In fact the spaceship that Dr.Pellgrino has designed is believed to be capable of achieving a maximum cruising speed of 92% of c⁴ or some 992,912,611 kph!⁵ At these sorts of velocities according to relativity time would slow by a third. This means that 6 years would pass on earth for every two years on board ship, although we’d never be able to explore the far reaches of the galaxy which are hundreds of light years away we could explore our corner of the galaxy. Alpha Centuri are next door neighbour for example is ‘only’ four-and-a-half light years away, travelling at maximum speed and taking the time dilation into account the crew will be experience travel times of a similar duration to other great explorers such as Columbus or Cook.

Valkyrie

The basic concept of Dr.Pellgrino's Valkyrie ship design is not new, however it has many subtle changes which overcome many of the previous designs problems. Up till now most spacecraft designs used a large thruster rocket at the base of the ship and therefore all the necessary support structure to hold the thruster. Valkyrie does away with all this sturcture as it is heavy, in spacecraft design weight is bad because it starts a downward spiral. Extra weight needs extra fuel to provide enough power to move the craft along, however the extra fuel itself generates weight and therefore requires still more fuel. This spiral continues until a spaceships total weight could easily become almost 99.7% fuel. In fact the scientists Donald Goldsmith and Tobias Owen calculated that a ship designed along the old methods would weigh some 400 million tonnes to be able to have the range to fly to the nearest stars, Valkyrie in comparison weighs a mere 200 tonnes with only half that mass being fuel. Alternative designs such as the Bussard Ramjet have worked around this problem, whereas the Valkyrie concept has simply scaled it down. The ship really only consists of an anti-matter containment pod feeding a reactor chamber. This is attached to a large magnetic coil and together they act as the engines, tethered to the power unit on a large cable is the crew/living quarters being towed some 10 kilometres behind. This in turn is towing another reactor, magnetic coil and containment pod on a similar cable 10km behind it, more on this second engine later. The whole arrangement is more like a water skier⁶ being towed by a speed boat⁷ compared to an ocean liner!

Matter/Antimatter Fuel.

This really does sound like science fiction but anti-matter does exist. Scientist all over the world have been creating small amounts of anti-protons in their atom smashers and particle accelerators for years. In fact in these colliders anti-protons are collected in magnetic ‘bottles’ called Penning Traps for future use. This is achieved by combining the anti-proton with an anti-electron or positron to form an atom of the element hydrogen however instead of becoming normal hydrogen this becomes an atom of anti-hydrogen. In the Valkyrie large amounts of anti-hydrogen are stored at -272 degrees Centigrade one degree above absolute zero in the magnetic bottles. At this temperature the anti-hydrogen forms into solid ‘white flakes’ that can be conveniently stored as fuel pellets. The engine operates by controlling the temperature of the anti-hydrogen so that it evaporates at a controllable and constant rate. This evapourated anti-hydrogen enters an atomic accelerator where it is accelerated to around 750km per second and thewn fired at a target containing normal hydrogen . Here the matter target and anti-matter stream crash into one another and almost all the mass is turned into energy as shown by the famous E=mc² equation⁸

So how is the Thrust generated?

Valkyrie uses two methods to achieve its thrust. The first is to use the energy of the matter/antimatter collison to trigger nuclear fusion within the extra hydrogen that makes up the target. The engine effectively becomes an anti-matter controlled fusion reaction. By controlling the rate of the evaporation the amount of fusion can be controlled and fine tuned. The thrust is created by directing a spray of 'heavy elements'⁹ created as a byproduct of the fusion reaction. These heavy elements leave the reaction travelling between 12 to 20 percent of light speed, they are then captured by a magnetic coil and forced into leaving the craft in the same direction thus providing thrust. This nuclear fusion based thrust is similar to earlier designs such as the Orion Project and the more sophisticated Daedalus project. However unlike these two designs which where more like strapping the spaceship to a large nuclear bomb Valkyries thrust is more like a nuclear power station, it is controllable reaction rather than a powerful violent uncontrolled one.

However the sharp eyed reader will have noticed that this first stage of thrust is still far from the claimed top speed of 92% of c. As the ship starts to approach 12 to 20% of light speed the fusion reaction is starting to run out of force, basic Newtonian physics states that if the exiting particles are travelling 12 to 20% we cannot move faster than this. However by increasing the rate of evapouration more anti-hydrogen meets hydrogen. There will be less free hydrogen for the fusion reaction but more fuel for the matter/anti-matter reaction. Eventually the fusion reaction will slow and then stop altogether as the only reaction occurring is the matter/anti-matter one. A lot of complicated physics takes place during these matter/antimatter reactions because instead of totally annhilating each other to form pure energy the matter and anti-matter also produce a particle called a meson. The mesons decay very swiftly but as they exit the ship they are electrically charged and are travelling close to the speed of light. This enables the magnetic coils to capture the force they generate and propel the ship up to its top speed. Confused you probably will be unless you’re a physicist but apparently the science is all correct!

By using the first stage of 'heavy' but slow moving particles the Valkyrie is accelerated up to 20% of light speed. Then by switching over to the 'light' but high speed particles Valkyrie is able to reach its claimed top speed. This is what makes the engine design on Valkyrie so new, the ships engine changes its thrust characteristics to suit the situation and it achieves this without using huge fuel reserves.

The Tether System

As mentioned earlier the Valkyrie ship consists of the reactor, magnetic coils and containment bottles towing a long cable that is attached to the small crew compartment. The reason for this is that the engine produces large amounts of gamma radiation. By towing the crew compartment 10km behind the engine you save on the effects of the radiation this can also be helped by placing a 20cm thick tungsten shield on this tether about 100 meters behind the matter/antimatter reactor. This shield acts like an umbrella creating a large shadow like area free from the dangerous gamma rays. The other advantage of this tether system is the second engine. When you wish to slow down to a stop it is simply a case of shutting off the first engine that is pulling you and switching on the second engine. This engine, which has been redundant up till now, fires in the opposite direction and can be used to slow the craft down. In fact if necessary as the the first engine is now longer needed it can be jettisoned thus shedding its extra mass and making the second engine more efficient.

Collision Avoidance.

As Han Solo once said,

Okay so the Valkyrie isn’t going to be travelling faster than light but even at our non-relativistic 92% of light speed a single piece of space dust could tear through the hull of the ship like a hot knife through butter. In fact a stationary piece of dust weighing 1 gram if struck by the ship travelling at 92% of lightspeed will impact with the same force as a 1 ton car travelling at 992kph¹⁰, and remember most space dust is not stationary! However Jim Powell and Dr. Pellegrino have solved this problem and worked out how to shed any excess heat the engine creates at the same time. First by pumping the heat into a tank of an organic fluid mixed with metal particles the heat can be transferred to the liquid, if this liquid is subsequently sprayed out in front of the ship as a fine mist that heat will be lost through radiation into space. As there are the metal particles embedded within the fluid droplets magnetic collectors can be used to continually recollect the spray for re-use as the ship accelerates into the mist cloud. This cloud is also what will protect from dust and meteorite impact. When the interstellar dust impacts into this field it's constituent particles will break up¹¹ and ultimately be recycled in the spray. The other advantage of the spray shield is that unlike a solid ablative shield it is continually replacing itself.

Far Flung Worlds.

So there we have it, a design of a machine which, in concept at least, could enable us to travel at 0.92% of light speed. Coupled with the recent breakthrough's in quantum teleportation for possible communications and perhaps we are already a step closer to the universe as imagined by science fiction writers already. The Valkyrie design could see within a generation or two the kind of exploration we have up till now only dreamt of. This generation's great-grandchildren could one day be staring down on to the surface of a planet in another star system. The future is out there, just waiting for us to grasp hold of it...

Acknowledgements.

Of course the Valkyrie design is a lot more complicated and goes into more detail than can be covered in this short article, if you are interested more about it can be read in Charles Pellegrino’s article about the ship here,
Project Valkyrie.
This single article has been the inspiration for this entry and as such any similarities are a coincidence of writing about the same subject matter. Dr.Pellegrinos article will always be the original item.