controlled local annealing would solve a great deal of the problem.
Basically, the heating from the sunlight hitting the craft, (and extreme cold on the dark side, with the object rotating), coupled with high exposure to energetic electrons and other charged particles, makes the material behave very strangely at the molecular and atomic levels. Crystals continue to grow, crystal boundries push against each other, and microfractures form in previously homogeneous materials.
Imagine a sphere made of an alloy that is carefully chilled from its amorphous, fluid state into a glassy solid. Such metallic glasses exist, and are very useful.
https://en.wikipedia.org/wiki/Amorphous_metalNow, we subject this sphere to the conditions found in space. The atoms in the glass begin to migrate into locally divergent concentrated populations, and away from the perfectly homogeneous distribution of the glass. Spontaneous
self-assembly into crystalline structures occurs. Some parts of the sphere are higher in concentration of one population of atom than another, resulting in different crystal morphologies. Differences in mechanical stresses causes crystals to favor growth in certain directions over others. This all results in the previously very strong, very durable and robust sphere of metallic glass, becoming a hodge-podge of crystals, with shear boundries between them, and mechanical compression/expansion forces being exerted against those boundries from the persistent heating and cooling of the material.
Ultimately, these combined forces and processes are sufficient to pop the sphere apart along those newly formed boundries.
This is how the structural integrity of steels and other structural components of long lived orbital craft degrades over time. There IS a way to combat this process, however.
Much like the process used to initially produce the ball of metallic glass we used in this hypothetical example-- Molten homogeneous mixture is rapidly chilled before any speciation and assembly can occur, creating an amorphous solid-- localized annealing and tempering systems installed through-out the vehicle could recondition the raw materials the vessel is made from, by heating the materials above the crystallization point-- Annealing-- then rapidly cooling them again, to either cause very small, disorganized crystals (normal tempering) or complete loss of crystal structure (glassification). Combined with structural redundancy (each girder in the structure is able to have 100% of its load borne by other girders, meaning it can effectively be taken out of service while the annealing refresh is performed, without the structure flying apart) the vehicle can retain its structural integrity as long as there is sufficient capacities for energy generation, delivery, and removal to keep pace with crystal growth in the materials.
I believe we have the necessary technologies to accomplish this. The problem is that redundant superstructure based constructions require sending more than the barest minimums to hold a craft together, INTO ORBIT.
That is hella expensive. The issue is not therefor possibility-- it is cost.
Author
Topic: AmeriPol thread (Read 4452289 times)