The Genius Behind The First Active Deflector Shield

on August 4th of 1972 a coronal mass ejection exploded out of the Sun at 2,800 km/s the solar wind and particle bombardment that traveled out across the solar system was so intense that it swept aside cosmic rays that usually ared from outside of the Galaxy and temporarily shredded half of the northern hemisphere's ozone laay geomagnetic storms ravaged hydroelectric plants nuclear detonation satellites fired false alarms and dozens of American magnetic sea mines off the coast of Vietnam spontaneously detonated but for any astronaut caught in the cosmic blast the radiation levels alone would have likely been a death sentence if our ambition as a species is to travel Out Among the Stars how do we replicate the magnetic Shield of Earth to protect ourselves from the cosmic radiation storms capable of pulling apart our DNA at the seams can we really build an effective deflector Shield I love finding places where sci-fi meets reality and understanding just how feasible actually engineering these systems might be it turns out we've actually been exploring the concept since the early 1960s and today we are very close to working out a scale down version of a system there are two types that I want to talk about today magnetic and electrostatic deflection systems and now as always I like to start simple so today is particle physics explain particle physics to a particle there are two primary sources forces of radiation out in the vacuum of space the first is solar particle events or spes that primarily contain protons with energies typically ranging from a few megga electron volts to a few hundred megga electron volts these are emitted during phenomena like solar flares or coronal mass ejections that we've covered in previous videos like how one day they might destroy the internet the unit of Interest here is the electron volt and it's a measure of the kinetic energy gained by an electron when accelerated by electrod with one volt potential difference between them now protons are more massive but still gain one electron volt of energy between these two electrons they just move slower as kinetic energy is masstimes the velocity squared a proton with one Mega electron volt of kinetic energy has a speed of about 13.8 million m/s or about 4% the speed of light a proton with 100 megga electron volts though of kinetic energy has a speed of about 129 million m/s or 43% speed of light if we want to stop a particle with 100 Mega electron volts in its tracks we need to absorb that energy by applying a massive decelerating force and actually although 43% of the speed of light sounds fast these particles are comparatively when it comes to Grand space terms low energy but they do come in very large numbers during things like solar particle events as a result astronauts typically avoid them either by shielding using materials that can absorb or deflect incoming radiation such as in spacecraft holes or or just by timings planning missions to minimize exposure such as avoiding solar maximum periods when SES are more frequent the second major type of dangerous particles are Galactic cosmic rays or gcrs these are high energy particles originating from outside of our solar system believed to be produced by Supernova active Galactic nuclei and neutron stars Galactic cosmic rays consist of a mixture of high energy protons about 85% alpha particles about 14% and a small fraction of heavier nuclei including things like iron these are collectively known as HZ e ions for high H charge Zed just to confuse you and E for energy nuclei the energy ranges of these gcrs are extremely broad extending from about 100 Mega electron volts to over 3 XA electron volts for the all my God Particle detected in 1991 the all my God Particle was assumed to be a proton and it was calculated that it had the same kinetic energy as a baseball traveling at a 100 kmph but as the oh my God Particle was a fundamental particle a proton it was smaller and less massive than a baseball meaning that it had to have velocity significantly faster to have the same kinetic energy it was calculated that it was moving at about 99.99 99999999999999999 times the speed of light at the speeds these particles are moving they can pretty much punch through anything in their way and they do considerable damage when they do so counterintuitively using conventional shielding approaches to try and stop them actually makes them even more dangerous it breaks a single Ultra highspeed particle into many very high-speed particles that spray out like a shotgun blast of radiation as a result a different approach to protecting deep space Travelers is needed and as of the 1960s NASA started to explore multiple approaches to what it refers to as active shielding Concepts a force field capable of shielding spacecraft and their inhabitants from the violent particle storms of space the basic principle behind an active shield for protecting spacecraft and astronauts from space radiation starts with the observation that a large majority of high-speed particles are charged and as a result if these particles encounter a magnetic or electrostatic barrier as they hurtle their way through space these fields will apply a repulsive or deflecting force to these particles and so reduce their potential for harmful impact on humans and sensitive equipment we said before if we want to stop a particle in its tracks we need to remove its kinetic energy taking electrostatic approach this would mean that to stop a proton flying through the Galaxy with an energy of 200 Mega electron volts we would need two electrodes with 200 Mega volts between them to put that in context 200 million volts is comparable to the voltage delivered in lightning and at the moment that's far beyond what we can actually produce even with things like old school atom smashes the record achieved was about 30 2 megga volts because of this most scientific teams were quick to write off electrostatic approaches due to the exceptionally high voltage requirements for these systems so as a result magnetic deflection mechanisms became the primary focus of spaceflight groups around the world the active radiation shield for space exploration missions which if you say with an American accent sounds like awesome but if you say with a British accent sounds like awm this approach was established in 2002 by the European Space Agency so I think they were intending on the latter pronunciation with the help of CERN in their proposal they wanted to develop on cern's expertise in high power superconducting magnetic field creation to produce a device capable of shielding deep space missions their ideal design looked a lot like a miniature version of the atlas experiment which sets the record for the largest magnet in the world at 26 M long and 20 m in diameter for the four superconducting coil assemblies with an internal volume through which usually passes a high energy particle beam Collision experiment but in their proposed designs would house instead a deep space exploration team potentially for many years at a time this exceptionally High magnetic field produced by the device would divert incoming high-speed particles protecting the crew aboard some studies and simulations that I found suggest that magnetic shielding could reduce exposure to Galactic cosmic rays by approximately 30 to 50% for Missions outside of Earth's magnetosphere such as trips to Mars but with this came a few problems as most people that have been on the internet for the past couple of years are aware superconductors are actually quite hard to work with they usually work at very low temperatures which is why each time someone announces they have come up with a room temperature superc conductor everyone on the internet loses their mind one of the big problems of superconductors in space is that most require active and continuous cooling usually in the form of something like evaporative liquid helium which requires periodic resupplies of that helium to continue working which isn't an easy problem to solve if you are sending a probe into deep space the other problem is power draw even with these superconductors these systems draw huge power requirements for Atlas tens of thousands of amps flowing through the coils which at the moment we aren't very good at dealing with in space as most systems rely on either solar panels or nuclear thermal batteries though we did look quite recently at teams looking to put micronuclear reactors on the moon in the next decade alternative materials like rebco a high temperature superconductor are capable of Opera ating at liquid nitrogen boiling temperatures rather than helium and as a result are much easier to work with building on this idea the European Space Agency developed the even larger sr2s the space radiation superconducting Shield which sadly followed a similar fate as it predecessor but focused on the design and testing of superconducting coils capable of generating the magnetic field required for effective radiation deflection the magnets that they required needed to be lightweight energy efficient and capable of operating in the harsh conditions of space the end result that they proposed looked something like this a pidal magnet protecting a small Human Habitat with proportion systems in the rear the magnetic force it could produce was calculated to be around 12 Tesla per meter but to support the system heavy structural beams were required weighing in about 100 tons of material in total these supports would not be entirely protected by the magnetic fields which brings us to a problem we talked about earlier as a result if high energy particles hit these structures they produce a Cascade of secondary particles turning one damaging particle into a shotgun blast of radiation the conclusion of this proposal was that increasing shielding power alone was one thing but it was useless if it wasn't coupled with an appropriate choice of material and structural design in order to limit the generation of secondary particles so the aim changed to produce a design that minimized support structures weights and chances of secondary Decay the final design of the sr2s was the pumpk which involved arranging superconducting coils in a way that creates a toroidal or donut-shaped magnetic field around the spacecraft this design allowed it to provide a uniform and adequate magnetic field coverage around the inhabited areas and null or minimal at least magnetic field inside the habitat so it didn't damage the sensitive equipment the term for a design that achieved very low secondary particle generation was radiation transparent and this was a very good approach to initial designs but it still remained four to six times the mass of the rest of the module and that would require multiple launches and then assembly in orbit and ultimately an appropriate cooling system was never actually identified so it still remained an untested design on the drawing boards it wasn't until 2022 that we saw the lowest weight version of superc conducting rings in the cosmic radiation extended warding halbach Taurus or the crew hat as if that name makes more sense the halbach array is a special arrangement of magnets that amplifies the field on one side of the array while canceling it out on the other side and it's often used in conjunction with superconducting magnets this property makes hbac arrays particularly useful in applications where a concentrated magnetic field is required in a specific area or Direction like on magnetic levitation trains each semi-elliptical array faced either directly outwards or perpendicular to the crew quarters producing an enhanced external magnetic field that diverts Cosmic radiation particles while producing close to no magnetic field components in the AST habitat simulations shows that it was capable of diverting about 50% of cosmic rays below one giga electron volt in energy and according to NASA this is sufficient to reduce radiation dose absorbed by astronauts to a level that is less than 5% of the lifetime excess risk of cancer mortality levels if this system was then combined with conventional passive shielding it could offer a total shielding of about 70% to Galactic cosmic rays and the design was one of the lightest ever proposed weighing in at a mere 25 5 tons however with all close approximations come catches the energy to power this system would have equated to the full power supply capability of the ISS around 60 KW which just can't be supported by current spacecraft so this design Still Remains difficult to deploy on missions this felt frustratingly like the final dead end but recently a fundamentally different approach has started to shine one previously written off long [Music] ago as cosmic rays tend to be protons which have positive charge they can be deflected by other charged objects we started this conversation with the idea of the electron volt as the kinetic energy gained by an electron or proton when accelerated by electrodes with one volt of potential difference and that for highspeed charge particles stopping them with electrostatics was impossible because of the voltages required but if we just want to divert a particle this requires significantly less energy this was the view of stojan M zov's team at JPL and Dan Fry's team at NASA's Johnson Space Center for them previous attempts gave up too early without any conclusive tests instead they were going to tackle the issues head on to get closer to an answer the simplest shielding setup possible would be a dipole with a positively and negatively charged electrode this is the starting point the research team began with for their particle deflection equivalent of a wind tunnel experiment they built a system capable of scanning a beam of protons past an electrode pair that would then strike a phosphor screen that could record the impact point of the beam when no voltage was applied to the system only the Shadows of the electrodes are visible but as the voltage was increased the charged protons began to be deflected from passing between the electrodes creating a shield of protection for in this case any teeny tiny astronauts behind the array munov and Fry knew they needed to make an assessment of thousands of possible designs so they wrote an entire code package called the active shielding particle Pusher designed to use modern gpus to their limits which let them simulate over 10,000 designs over a 2-year period of research they found that grid-shaped structures were particularly promising and reasonably underexplored and offered the tantalizing possibility of using far lower voltages to provide shielding effects if these designs could be scaled up and tiled to form a large mesh cage enclosing the entire spacecraft then cosmic rays would be deflected in a somewhat reminiscent version of a faraday cage simulation is one thing though experimental testing was still required particularly as complex effects such as plasma interactions are possible with high electric Fields the best way to test this setup might have been to build a shielding system and lower it into a beam line at somewhere like the large hyron collider to measure its particle deflection capabilities however as particle accelerators require a near perfect vacuum to accelerate particles and vacuum Chambers and particle beams just don't come in the dimensions sufficiently large for testing a fullsize model of this approach isn't feasible instead scale down models would be needed which sounds simple until you remember that physics often doesn't like to scale and that's true yes of quantum into general relativity and they don't play nicely with each other but it's also relevant for simpler physics a human-sized ant would be so heavy its legs simply couldn't support it and that's because volume increases by the third power but cross-section increases by the squared power once the fundamentals of the system were understood a stacked C like version of the design was constructed with negative electrodes at the corners and positive electrodes in the center this was placed into a larger vacuum system with a particle accelerator firing two Mega electron volt protons by charging the system to just 50 Kilts it gave a detected shadow on the phosphor screen that looked like this we can use the shadowed areas in this image as a proxy for shielding efficacy kind of like chain mail shielding we aren't looking at perfect uniform coverage but about 50% % blocking capability and although these experiments were performed with lower energy 2 Mega electron protons the scaling work conducted by the team confirms it should be possible to block 50% of 200 Mega electron volt protons with a comparatively low 1 megga volt Beyond this initial result two layers of this system could then be stacked and offset to improve the shielding capabilities of the system and plug the gaps but even with this design as it stands a 50% reduction in high-speed cosmic rays means that missions that are radiation exposure time limited can be extended to twice their operational lifetime essential for future Mars and deep space missions also this approach doesn't require superconducting level cooling for magnetic approaches or the heavy structural members to support the powerful magnetic fields generated this as a result removes the majority of the weight launch costs and probability of secondary radiation Cascades that limited the magnetic field approach but the biggest breakthrough here is that it conclusively demonstrates that high energy particles can be deflected at relatively low voltages transforming electrostatic deflection from an abandoned Fringe approach into a potential front runner in this field the next steps for this team are to continue to optimize simulate and test their 3D designs it'll be an exciting field to watch for the next few years and we may sooner than expected be capable of venturing Out Among the Stars protected by a deflection Shield pulled straight out of Science Fiction if you enjoyed this video I have a deeper dive on the most powerful particle ever measured the oh my God particle and its recently discovered cousin which you can find here or wherever I left it check it out thank you very much for watching I'll see you next week goodbye

Channel: Dr Ben Miles

Views: 210,579

Keywords: science, future, breakthrough

Id: ApYGMzPgzuo

Length: 17min 48sec (1068 seconds)

Published: Sun Apr 07 2024