Short science fiction by Torn MacAlester



Why is fusion so important?

There are many answers.  One is that it enables many items from sci­ence fic­tion. Space explo­ration itself is rev­o­lu­tion­ized with many dif­fer­ent schemes for fusion engines. The ben­e­fits are main­ly about pow­er. For fusion, there is a lot of it.

In sci­ence, one can look at a peri­od­ic table of ele­ments.  You will notice the mass­es of a Hydro­gen is 1.00784 atom­ic mass units. The mass of Heli­um, the next heav­i­est ele­ment, is 4.002602 atom­ic mass units.  Four Hydro­gen atoms have a mass of  4.03136, a dif­fer­ence of 0.028754 atom­ic mass units. When fus­ing those 4 hydro­gen into heli­um, that extra mass is turned into ener­gy using Ein­stein’s famous for­mu­la E=mc^{2}. For this case, 0.028754 amu = 4.774716716e-29 kg gives 4.29e-12 Joules of ener­gy.  This ener­gy den­si­ty is about 10 mil­lion times greater than coal.

For space trav­el, the mass is your ene­my. Fusion pro­vides ener­gy den­si­ty far bet­ter than any oth­er source. And it has the advan­tage of con­tin­u­ing to work at dis­tances far from the Sun where solar pow­er becomes use­less.  It can run elec­tric dri­ves or even fusion pow­ered dri­ves.   Here are some inter­est­ing arti­cles on fusion.

In sci­ence fic­tion, fusion is assumed to be the nec­es­sary ener­gy source for a type I civ­i­liza­tion on the Kar­da­shev scale.  It seems to be the log­i­cal pro­gres­sion of Earth advanc­ing into a type I civ­i­liza­tion is the advent of nuclear fusion as a pow­er source. One could argue that even a type II civ­i­liza­tion is enabled by nuclear fusion.


Here is a nice sto­ry from 60 min­utes that was 60 years in the making.