2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/35096Launched more than thirty years ago and now drifting in space with no further contact, the Pioneer 10 and 11 spacecraft are currently at the center of a small but developing concern: are they under the influence of an anomalous acceleration that reflects new, yet unknown physics, or merely experiencing some unexpected technical problem ? The proposals vary from basic engineering principles to extra spatial dimensions, but most probably an answer can only be obtained after a dedicated mission is underway.Talk presented by O.B. at the XIV Encontro Nacional de Astronomia e Astrof\'ısica, Angra do Hero\'ısmo, Açores, 22-23 July 2004. 9 pp. 3 figsGeneral Relativity and Quantum Cosmologytext