Spacelift

Ob branju tega članka (ki ni tako komercialno sponzoriran ) pa ugotoviš, da ta projekt še ni tako blizu, še posebej ker se z novim in novim razmišljanjem o teh dvigalih porajajo tudi možni problemi (kaj storiti proti pretrganju ponekod zelo tankega kabla), poleg tega pa nove raziskave kažejo, da vrv iz ogljikovih cevk le ni tako močna, kot so sprva domnevali.

Zanimiv pa se mi je zdel tudi tale opis dinamičnih vplivov pri pretrganju enega kabla v snopu kablov, za katerega zaenkrat ni rešitve:

It is not enough, however, that other fibers be able to take over the load of a failed strand — the system must also survive the immediate, dynamical effects of fiber failure, which generates projectiles aimed at the cable itself. For example, if the cable has a working stress of 50 GPa and a Young's modulus of 1000 GPa, its strain will be 0.05 and its stored elastic energy will be 1/2 × 0.05 × 50 GPa = 1.25×109 joules per cubic meter. Breaking a fiber will result in a pair of de-tensioning waves moving apart at the speed of sound in the fiber, with the fiber segments behind each wave moving at over 1,000 m/s (more than the muzzle velocity of an M16 rifle). Unless these fast-moving projectiles can be stopped safely, they will break yet other fibers, initiating a failure cascade capable of severing the cable. The challenge of preventing fiber breakage from initiating a catastrophic failure cascade seems to be unaddressed in the current (January, 2005) literature on terrestrial space elevators. Problems of this sort would be easier to solve in lower-tension applications (e.g., lunar elevators).

Bo pa to enkrat zaživelo v praksi, vendar bomo do takrat pokurili še veliko vodika, kerozina in podobnih sestavin pri izstreljevanju raket.