"First, the main problem is one of energy. In the same way that a car needs gasoline, a time machine needs to have fabulous amounts of energy. One either has to harness the power of a star, or to find something called “exotic” matter (which falls up, rather than down) or find a source of negative energy. (Physicists once thought that negative energy was impossible. But tiny amounts of negative energy have been experimentally verified for something called the Casimir effect, i.e. the energy created by two parallel plates). All of these are exceedingly difficult to obtain in large quantities, at least for several more centuries!"
https://mkaku.org/home/articles/the-physics-of-time-travel/
Spaceship(Star)
"The US TR-3B nuclear-powered anti-gravity aircraft had entered the practical stage."
https://defenceview.in/the-worlds-first-nuclear-powered-fighter-jet-could-fly-for-15-years-without-landing/
Fusion(Power Of A Star)
China's Artificial Nuclear Sun
Feds confirm historic fusion ignition at Lawrence Livermore National Lab
"fusion is the process that powers the sun.
Two light hydrogen atoms, when they collide at very high speeds, fuse together into one heavier element, helium, releasing energy in the process."
https://phys.org/news/2022-12-nuclear-fusion-harnessing-power-stars.html
"a “Plasma Compression Fusion Device” in 2019, it was either a giant breakthrough – or mad science. According to the patent application, the miniature device could contain and sustain fusion reactions capable of generating power in the gigawatt (1 billion watts) to terawatt (1 trillion watts) range or more. A large coal plant or mid-size nuclear powered reactor by comparison produces energy in the 1–2 gigawatt range"
https://www.forbes.com/sites/arielcohen/2021/02/08/what-is-behind-the-us-navys-ufo-fusion-energy-patent/?sh=343c68d44733
Solar Winds(Fuel Of A Star)
"The vast majority of solar wind is made of ionized hydrogen (individual protons and electrons), followed by less than 10% ionized helium."
https://interestingengineering.com/science/solar-wind-sun-space-weather
"0.127 particles per cubic centimeter, or about 120 hydrogen atoms in a space the size of a quart of milk."
https://phys.org/news/2020-10-evidence-neighborhood-space-stuffed-hydrogen.html
"As the pilot and crew travel in space, outside the magnetic field of a world, water from a tank is electrically separated into oxygen and hydrogen. Waste carbon dioxide that isn't used for the onboard garden, and hydrogen (helium if the machine is using a fusion reactor) is slowly, constantly fed into the inside curves of both accelerators.
The high speed particles go out through straight lengths of pipe, charged like the loops and in speeding out into space, push the machine along."
https://nexusnewsfeed.com/article/science-futures/nikola-tesla-s-flying-saucer-electromagnetic-field-lift-experiments/