Fusion Rockets - The Real Mars Express

2044 the first somewhat unusual rocket engine is being tested its mission reach mars in record time consuming the least amount of fuel something that is only possible with the power of fusion the most powerful reaction within human reach when two nuclei smash against each other at incredible speeds and temperatures it fuses becoming a more massive one releasing an enormous amount of energy one gram of deuterium tritium fusing releases 845 billion joules of energy that is enough to power almost 7 800 homes for one day or 21 homes for an entire year to realize the same thing with conventional methods of energy production you would need 88 tons of coal or 0.7 kilometers square of solar panels while fusion is a problem on its own using the energy in a controlled way to steer a spaceship is another extreme fortunately there are proven ways to do this and when it becomes available it will dramatically accelerate not only mass colonization but the entire solar system colonizing mars depends entirely on how fast we can get there and how much resources can be transported chemical propulsion technology limits that to a tiny amount about 1.2 percent of the total rocket weight is dedicated to resources that can be sent directly to mars from earth's surface with current technology it would take decades to settle just 100 people on mars living comfortably not because it takes months to get there but more as each launch costs millions of dollars without any return of investment in the near future the only way to decrease the cost of space travel would be with newer more efficient engines that can transport larger payloads several technologies are on the horizon but none of them will ever be as efficient or as fast as fusion driven rockets [Music] hello everyone subject zero here established rocket technology is limited by the total amount of energy available in chemical reactions hydrogen which holds the highest heat of combustion energy at 141.8 million joules per kilogram provides the best specific impulse to visualize how efficiently a reaction mass engine creates thrust scientists like to use specific impulse abbreviated as isp which gives us a more simplistic view on how efficient a given engine is in terms of how it uses the mass of the propellant it can be expressed as the exhaust velocity divided by the gravity standard which gives us specific impulse expressed in seconds since the gravity standard is always the same specific impulse is directly proportional to the effective exhaust velocity these in turns translate to the mass flow rate of the exhaust which further translates into payload capacity in theory the maximal isp for a hydrogen chemical reaction is 502 seconds the space shuttle orbiter with one of the most efficient engines ever used reached 453 in vacuum with an average mass flow rate of 1 ton per second falcon 9 first stage with its specific impulse of 311 seconds has 2.5 times the mass flow rate these engines are powerful but they need exorbitant amounts of fuel to transport things falcon heavy can send about 16.8 tons of payload straight to mars sounds like a lot of stuff but food alone for the astronauts for the entirety of the trip would amount to almost 9 tons or more than half the capacity if we consider 100 people it would require almost 9 falcon heavy launches with a cost at the lowest of 800 million dollars adding other things such as habitat vehicles oxygen water and so on will probably double or even triple the final cost the problem is that the payload to mars is only 1.2 percent of the total mass of the rocket cutting expenditures is key for future space endeavors and fusion propulsion promises exactly that the proposed and most plausible system that is being researched by nasa is called electromagnetically driven fusion propulsion this engine uses electromagnetic fields to achieve fusion and control the exhaust energy at its simplest it's broken into a few parts a shadow shield a plasmon injector shark absorbers propellant injector electromagnetic coil and a magnetically insulated expander to achieve fusion this engine creates a plasmoid or a structure of plasma that is contained by the magnetic field think of it as a magnetic soap bubble when the field is disturbed a smaller bubble detaches itself from the bigger one inside this magnetic bubble elements for fusion such as deuterium and tritium are contained the only caveat here is that this bubble can be manipulated with the extreme magnetic field the plasmoid goes through a series of magnets compressing the plasma right around the converging shell section the plasmoid is compressed to levels where fusion is achieved with an expected gain of 200. this energy is released in the form of neutrons and helium-4 most of the energy from neutrons are lost in this reaction and the remaining energy from helium is transferred to the magnetic field in the form of a violent explosion to dampen this shock absorbers work to counter the extreme acceleration the main complication of this method of propulsion is that the divergent magnetic nozzle poses a problem to the newly ionized plasma created by the reaction neutrons are scattered in every direction damaging everything while helium is trapped in the magnetic field generating negative trust to solve this problem a proposed metal liner is used to shield the plasmoid this liner will most likely be made out of lithium that helps the system in two ways first it serves as a shield that absorbs the energetic neutrons and second it works as a magnetic blanket that after the explosion its atoms ionizes and the plasma expands inside the divergent nozzle this makes it easier for the magnetic field to interact with the product and transform the energy of the plasma into a directed propulsive trust this interaction protects the chamber wall from the extreme heat generated almost eliminating entirely the need of a radiator according to initial projections this engine creates a jet power of 36 megawatts with a 5 000 second specific impulse all of this translates to a mission that would take only 90 days of traveling with a 30-day stay totaling 210 days this is important for multiple reasons first it cuts dramatically the acceptable levels of radiation dosage that each astronaut will receive .66 seavers is the expected dose of radiation for current chemical rocket space missions this is equivalent to [Music] 2.65 million airport security screenings working as a flight attendant for 440 years 22 full-body ct scans or living on board the iss for four years straight when sievert is the maximum dose allowed by nasa for astronauts during their entire career anything more the damage is irreversible 5 sieverts and you're dead using fusion propulsion the proposed mission time will bring that number down to less than point 15 sieverts allowing astronauts to maybe work multiple missions it is estimated that the entire trip will require about 69 terajoules of energy that is equivalent to the same energy as little boy bomb dropped in hiroshima with fusion we would only need about 120 grams of tritium and 80 grams of deuterium a larger quantity of lithium propellant will be required amount to about 42 of the total ship weight with an incredible isp of 5 000 seconds it means that almost 50 percent of the ship will be dedicated to crew habitat almost the size of the space shuttle orbiter among other technologies required to land and survive this is a long shot in comparison to other methods such as chemical rockets and nuclear with 450 and 1000 isp respectively so what's holding this technology back well the answer is quite simple the liner drive achieving fusion with the system described here though more research is needed is already well understood and proven now focusing liners to envelop the plasmoin technology is still under research ongoing studies at the university of washington have succeeded in manipulating liners but nothing in terms of fusion yet currently they use aluminum liners to study the magnetic field and how much neutrons can be filtered by such arrangement though liner compression by magnetic fields is an evolving pitch the good news is that obtaining fusion through this method has been demonstrated and is well understood at least fusion isn't the problem for this technology and it's not 30 years away maybe 23. alright folks that's it we're done here [Music] you

Channel: Subject Zero Science

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Keywords: Subject Zero Science, graphene, space travel, nuclear propulsion, mars travel, nuclear power, nuclear rockets, what if, elon musk, elon musk snl, what if marvel, space travel sleep, what happens if you dont sleep

Id: STtXdpD8LtM

Length: 10min 54sec (654 seconds)

Published: Thu Jun 03 2021