The older Jaegers are powered by fission reactors, which we have had since the early 1950s

The first fission reactor to produce electricity was started in December 1951 in Idaho USA, operated by Argonne National Laboratory [1]

Considering that humanity had roughly 75 years to refine fission reactors to be more powerful and portable, and lots of funding to do so -- giant monsters help with that -- it is a realistic use of fission reactors

• Drone Jaegers are controlled remotely by a single pilot, and the pilot does not need to be drift-compatible, as the drone’s AI handles the Jaeger’s complex processes as if it was a copilot.

• Shao Industries (a major Chinese tech company) is the designer and producer of the newly revealed Drone Jaegers

• The drones are highly controversial, as supporters of the traditional Jaeger program as well as Kaiju worshippers (of course they exist) oppose their deployment, with the manned Jaeger supporters claiming the drones are not as reliable as crewed systems.

• To the surprise of absolutely nobody, the drones turn evil immediately, as Newton Geiszler was actually working for the Kaiju the whole time and somehow implanted living Kaiju tissue into their computer cores without anybody noticing.

• Currently, drones do exist, though not at the scale that the movie has them in (plus they don't have the flesh of monsters from another dimension in them most of the time)

• As of 2019, in the United States alone there were roughly 1.5 million commercial and hobbyist drones [2]

• Again, considering that humanity would have had another 15 years from current technology to refine drones, it is again a realistic portrayal of drone technology

Newer Jaegers are powered by portable fusion reactors, which currently is still in research, and constantly "ten" years away from being created

Furthermore, a fusion reactor that outputs enough energy to move an entire Jaeger and be portable is still quite far away from being completed

Currently, two main fusion reactors are in the process of being created

• One reactor is named Sparc and is being developed by researchers at MIT and is expected to be finished in 2023-2024 [3]

• The other main reactor is a multinational effort in France called ITER (International Thermonuclear Experimental Reactor) and has been under construction since 2013, and is expected to produce a fusion reaction by 2035 [3]

As the movie is set in 2035, it's very possible with the increased funding that fusion reactors developed faster than predicted, but it's slightly less realistic

The Drift is an unexplained neural interface between the two Jaeger pilots

• The pilots had to be compatible with a close bond (either emotional or familial)

• If one pilot is incapacitated, controlling the Jaeger will be almost impossible for the other one, and will potentially cause severe neural damage

• Small Jaegers may only need one pilot

• This technology is currently being researched in real life. According to an interview with a Queensland Brain Institute PhD student, a close relationship between the pilots would probably improve their performance, as real-life Brain Machine Interface (BMI) setups have shown that two monkeys using their combined brain activity to control a robotic arm performed better when their brain activity was more correlated [4]

• Additionally, current BMI technology is highly accurate with an invasive array of electrodes implanted in the brain, but with non-invasive technology (the movie had a helmet that went over the pilots' heads), currently we can only detect whether the person is moving their left or right hand within about three seconds, then translate that into an action [4]

• This is somewhat realistic as BMI technology has continued to improve over the last couple decades and will most likely continue to do so, possibly reaching the level of The Drift by 2035

• It is currently impossible to make humanoid-like machines anywhere that big, mostly due to the square-cube law

• The square-cube law states that if something doubles in size, the volume/mass increase by a factor of eight, but the cross-sectional area of the legs only increases by four times

• This means that the Jaegers would have to be made out of incredibly strong, futuristic materials in order to not break apart under the strain

• This is also somewhat realistic, as another 15 years of well funded research could lead to stronger and improved materials

• Liwen states that quantum data cores allow for remote control of the Jaegers, and that only one pilot would be required, as the quantum data core could handle the Jaeger’s complex processes as if it was a copilot

• This is a classic movie trope, which is putting the word "quantum" in front of some techy thing to make it seem more powerful and mysterious

• In reality, quantum computers are still very early in the works, but they are getting better and better

• Google currently has a 53 qubit (quantum bit) computer and plans to build a million-qubit computer within 10 years [5]

• The portrayal of quantum computing in the movie is realistic in that we will most likely have quantum computers that are powerful enough to be useful by then, but an unrealistic part is that what the "data core" actually is is never actually explained -- perhaps some mix of a CPU and disk