(ORDO NEWS) — NASA and Elon Musk dream of Mars, and manned deep space flights will soon become a reality. You will probably be surprised, but modern missiles fly a little faster than missiles of the past.
Fast spaceships are more convenient for a number of reasons, and the best way to accelerate is with nuclear powered rockets. Compared to conventional fuels or modern electric solar-powered rockets, they have many advantages, but over the past 40 years, the United States launched only eight nuclear-powered missiles.
However, last year, laws on nuclear space flights changed, and work on next-generation rockets has already begun.
At the first stage of any space flight, a booster rocket is needed – it launches the ship into orbit. These large engines run on combustible fuel – and usually, when it comes to launching missiles, they are in mind. In the near future they will not go anywhere – like gravity.
But when the ship goes into space, everything becomes more interesting. To overcome the force of gravity of the Earth and go into deep space, the ship needs additional acceleration. And then nuclear systems come into play. If astronauts want to explore something farther away from the Moon, much less Mars, they will have to hurry. Space is huge, and distances are rather big.
The reasons why fast rockets are better suited for long-distance space flights are two: safety and time.
On the way to Mars, astronauts face a very high level of radiation, fraught with serious health problems up to cancer and infertility. Radiation protection can help, but it is extremely difficult, and the longer the mission, the more powerful the shielding will be. Therefore, the best way to reduce the dose is to simply reach your destination faster.
But crew safety is not the only advantage. The longer flights we plan, the sooner we need data from unmanned missions. It took Voyager-2 (Voyager-2) 12 years to get to Neptune – and, flying by, he took some incredible pictures. If Voyager had a more powerful engine, astronomers would have had these photos and data much earlier.
So, speed is an advantage. But why are nuclear systems faster?
Having overcome the force of gravity, the ship must take into account three important aspects.
Thrust – what kind of acceleration the ship will receive.
Weight efficiency – how much traction the system can produce for a given amount of fuel.
Specific energy intensity – how much energy a given amount of fuel emits.
Today, the most common are chemical engines – that is, conventional flammable rockets and electric solar-powered rockets.
Chemical propulsion systems provide great traction, but are not particularly effective, and rocket fuel is not too energy intensive. The Saturn 5 rocket, which delivered astronauts to the moon, gave out 35 million Newtons of power during takeoff and carried 950 thousand gallons (4,318,787 liters) of fuel. Most of it went into putting a rocket into orbit, so the limitations are obvious: wherever you fly, you need a lot of heavy fuel.
Electric propulsion systems produce traction using electricity from solar panels. The most common way to achieve this is to use an electric field to accelerate ions, for example, as in a Hall thrust induction motor. These devices are used to power satellites, and their weight efficiency is five times higher than that of chemical systems. But they give traction much less – about 3 Newtons. This is only enough to disperse the car from 0 to 100 kilometers per hour in about two and a half hours. The sun is essentially a bottomless source of energy, but the farther the ship moves away from it, the less useless it is.
One of the reasons why nuclear missiles are particularly promising is their incredible energy intensity. Uranium fuel used in nuclear reactors has an energy intensity of 4 million times higher than that of hydrazine, a typical chemical rocket fuel. And it’s much easier to deliver a little uranium to space than hundreds of thousands of gallons of combustible fuel.
What about traction and weight efficiency?
Two nuclear options
For space flights, engineers developed two main types of nuclear systems.
The first is a thermonuclear engine. These systems are very powerful and very efficient. They use a small nuclear fission reactor – such as those placed on nuclear submarines – to heat gas (such as hydrogen). This gas is then accelerated through the nozzle of the rocket to provide traction. NASA engineers estimate that flying to Mars using a thermonuclear engine will be 20-25% faster than a chemical-powered rocket.
Thermonuclear engines are more than twice as effective as chemical ones. This means that they deliver twice as much traction with the same amount of fuel – up to 100,000 newtons of traction. This is enough to accelerate the car to a speed of 100 kilometers per hour in about a quarter of a second.
The second system is a nuclear electric rocket engine (YERD). None of these have yet been created, but the idea is to use a powerful fission reactor to generate electricity, which will then drive an electric propulsion system like a Hall engine. It would be very effective – about three times more effective than a thermonuclear engine. Since the power of the nuclear reactor is huge, several separate electric motors will be able to work simultaneously, and the thrust will be solid.
YaERD is perhaps the best choice for extremely long-range missions: they do not require solar energy, have very high efficiency and provide relatively high traction. But for all their prospects, the nuclear power engine still has many technical problems that will have to be solved before commissioning.
Why are there still no nuclear missiles?
Thermonuclear engines have been studied since the 1960s, but they have not yet flown into space.
According to the charter of the 1970s, each nuclear space project was considered separately and could not go further without the approval of a number of government agencies and the president himself. Coupled with a lack of funding for research into nuclear missile systems, this prevented the further development of nuclear reactors for use in space.
But that all changed in August 2019, when the Trump administration issued a presidential memorandum. Insisting on maximum safety of nuclear launches, the new directive nevertheless allows nuclear missions with a small amount of radioactive material without complex interagency approval. Enough confirmation from a sponsoring agency, such as NASA, that the mission meets security recommendations. Large nuclear missions go through the same procedures as before.
Along with this revision of the rules, NASA received $ 100 million from the 2019 budget for the development of fusion engines. The U.S. Department of Defense’s Advanced Research Projects Agency is also developing a fusion space engine for national security operations beyond Earth’s orbit.
After 60 years of stagnation, it is possible that a nuclear rocket will go into space for a decade. This incredible achievement will usher in a new era of space exploration. A man will go to Mars, and scientific experiments will lead to new discoveries throughout the solar system and beyond.
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