Over the last few posts I have discussed the many dangers in space that threaten our star mission – the asteroid belt, comets, meteoroids, meteors, meteorites, space dust and debris etc. We also have to protect our astronauts from solar radiation from our sun as we travel away from it and from our new star as we approach it.
To protect our spaceship we need to be certain of detecting and deflecting anything that is on our trajectory or to make adjustments to our course to avoid larger objects that could smash through our defences.
At the relatively low speeds through the solar system at the start of our mission we are less vulnerable. But when we accelerate to half the speed of light we will need advanced detection and a highly sophisticated deflection system – a variable force field. Not just to deflect objects flying through space but also to defend ourselves against the unknown aggressor. We have to generate a low level barrier or field around our starship and be able to rack this up to a directional defensive shield against a major threat.
Detection – Detecting large objects on a potential collision course with our spaceship will be, relatively, more easy to achieve. We already have sophisticated Earth based telescopes and spaced based satellites eg Hubble that can detect objects hundreds of light years away. We also have equipment looking out for asteroids that could come near Earth and recently one did pass between us and the Moon but we had been tracking this since February 2012. However we must not be complacent as we were taken completely by surprise by the Chelyabinsk meteor in Russia and that object was 20 metres wide and weighed 10,000 tonnes!
However by the end of this century we will have developed systems to detect dangerous objects hundreds of millions of kilometres ahead of our trajectory with incredible precision. We will have to because when we are travelling at half light speed [approx 150,000 kilometres per second] an object 14 million kilometres away will be reached in 100 seconds [and quicker than that if it is moving towards the spaceship].
English: A sketch of Earth’s magnetic field. Shows that Earth’s interior has a magnet with its south Pole under Earth’s magnetic North pole. Earth’s magnetic field is generated due to a dynamo which creates a large currents in its outer liquid iron core. (Photo credit: Wikipedia)
Force Field – The best example to explain the concept of a force field is our planet. Earth is mankind’s spaceship and we are hurtling through space at 100,000 kilometres per hour as we travel around the sun.
And space is a dangerous place as I have described over the last few posts with billions of objects on collision course with us. If we also add solar radiation to the equation we are being continuously bombarded with lethal rays that would turn our planet’s surface to dust with no life possible. But Earth has two force fields with which to defend itself. Its molten iron core creates a magnetic field which stretches tens of thousands of kilometres into space and this magnetosphere deflects the deadly solar wind around the planet. Earth also has an atmosphere – a shell of gas that burns up most, but not all, of the billions of objects raining down on the ionosphere, the upper region. And this is exactly what we need to protect our spaceship – a low level field to divert the radiation and a more powerful, variable field to deflect potential impacts and for defence against possible alien aggression.
Low level field – Here we must emulate Earth’s magnetosphere and create a similar field around our spaceship. This will be required soon for journeys to Mars could become reality during the next 10 years. Scientists in the past have doubted if a big enough magnet could be carried on a spaceship to produce the necessary field. However recent work at the Rutherford Laboratories, UK indicates that a field extending 30 metres or so around our spacecraft can be generated from a very small magnet. This is because there is an interaction between the solar wind particles and the generated magnetic field which multiplies the shielding effect. The following is an extract explaining this…
‘Because the solar wind is a plasma made up of charged particles, it too carries a magnetic field. When the solar wind’s field meets the rocks’ mini-magnetosphere, the two fields clash, exerting a force on each other. Something has to give. Because the solar wind’s field is created by free-moving particles, it is the one that yields, altering its orientation to minimise conflict with the mini-magnetosphere’s field.
Some parts of the solar wind shift more easily than others. The positively charged protons have nearly 2000 times the mass of the negatively charged electrons, so the latter are much more easily deflected. The electrons stay at the surface of the magnetic bubble, while the positive charges penetrate further in.
This separation of positive and negative charges generates intense electric fields up to a million times stronger than the magnetic fields that created them. Subsequent solar wind particles hit these electric fields and are strongly deflected. The result is a shielding effect far more powerful than the magnetic field alone might be expected to provide.’
This work has been proved in the laboratory but has not as yet been trialled in space. However the results are very encouraging and the British laboratory is in discussions with NASA. The article is reproduced in full in New Scientist.
This shield would protect our astronauts from radiation for short [Mars] and protracted [star] missions and I have no doubt that this or similar technology will become reality within the next decade.
High level shield – now we are in the realms of science fiction eg Star Wars where a powerful, variable field can be generated at the touch of a button or more likely a sophisticated computer assessing the threat and applying the necessary defensive field. But this is where we will need to be by the end of this century if we are to go to the stars in 2150.
It is difficult to imagine a large enough permanent magnet that could achieve this. The technology might be an electro magnet powered by the spaceship’s nuclear reactor. But we have to consider all the complex equipment and computer systems on board that could be fried by a huge magnetic surge – and of course our astronauts!
I consider that the shell of our spaceship could be the electro-magnet with its huge, variable field acting outwards and away from the interior. It would be managed by our artificial intelligence computer as situations would have to be assessed and acted upon in fractions of seconds. See how Zec does it in The Blue People of Cloud Planet.
I would like to hear your views on this.