The speed of photons is the speed of light, and α particles travel at only about 5% of the speed of light; to use them to propel a spaceship of several thousand or ten thousand tons within a certain period of time is beyond human capability.
That is why Zhao Zongyao wrote it as an "overview"—he himself felt it was impossible to achieve in his lifetime...
For the base, the situation was even more so. Lin Ju's newly assigned task was to research a fusion radiation thruster with a thrust of 1000 tons. Tentatively throwing in ten million, the progress was still zero, not even reaching the lowest threshold of 0.1%, far exceeding the current world's capabilities.
However, this at least showed that radiation propulsion was feasible, especially since the base currently had no strength to conduct research on it.
Even laser-constrained inertial plasma fusion, the third-generation fusion technology achieved in that parallel world, was technically so challenging that it was beyond reach.
