The study of the stability of an astrophysically interesting nucleus ⁷³Rb was performed by searching its β⁺ and proton decay at the ISOLDE facility at CERN. Light rubidium isotopes were produced in a spallation reaction of a niobium target induced by a pulsed 1 GeV proton beam. The previously reported proton-unbound character of ⁷³Rb was confirmed and the upper limit for its production cross-section was reduced by more than one order of magnitude.