This is another name for the temperature of the cosmic background radiation which has a temperature of 2.7 K. No object in the universe can, for long, have a temperature lower than this unless it is done artificially in some small laboratory using a specially-shielded cryostat. This is, however, not the temperature of space itself, but only the primordial fireball radiation left over from the Big Bang which contributes about 400 photons per cubic centimeter of space...everywhere.