SORRY TO BE NEGATIVE HERE! Do you mean like blowing up 2 or more space shuttles and a 3rd (at least) in orbit now TODAY wondering if it will land safely or explode on re-entry?

For the shuttle program they threw the rocket scientists out of upper- and much of middle-management.  The MBAs they substituted ashcanned the old "belt and suspenders" approach, substituting "design for success" (i.e. assuming everything works, not that Murphy's law rules) to save money.

Have your mother read through that site if it is too difficult for you.

(So make it 23% bigger in each dimension and get more power than a darrieus could without the materials and metal fatigue issues.  Savonius rotors are strong and can be made out of sheet material - flat and bended - which is inexpensive and easy to form and join.)

Yes they did a bunch of work with the eggbeater-style darrieus, and didn't get to a really practical design.  But the latter is not too surprising:  Darrieus style mills have forces that change direction radically every rotation.   You also have turbulence when the blades are downwind of other blades or the hub.  And NASA did a bunch of work on the blade profile so it would stall-furl and produce a flat power output (at the design power for the genny/transmission) for a range of wind speeds, which throws a bunch MORE turbulence at the downwind blades - a price worth paying to keep the high TSR blades from trying to go supersonic in a storm.

With thin blades and strong oscillating forces you flex the metal.  NASA decided to build it out of aluminum to keep the weight down.  But aluminum has terrible problems with metal fatigue when it flexes, stress-hardening at a small fraction of its yield strength.  So a design like theirs, as with an aluminum-frame aircraft, has a strictly limited life - and if you don't disassemble it once it gets elderly it will do it for you.