This important measurement was made using Cassini's INMS instrument, which detects gases with the goal of determining their composition. INMS was designed to sample the upper atmosphere of Saturn's large, smoggy moon Titan. However, after Cassini's surprising discovery of a tall plume if icy spray erupting from cracks on Enceladus in 2005, planetary scientists turned its detectors to that small moon.
Scientists, seekers of truth by definition, would approach the subject from the null point of view, attempting to prove, in this case, that NASA DID go to the moon. Because the hoax theorists are taking the opposite tack, and because they stretch their case based solely on the photographic evidence, one must suspect both their academic pedigree and their intentions.
On March 27, 2012, Cassini made its closest flyby yet over Enceladus's "tiger stripes". In a string of enticingly close passes over the dazzling moon, the spacecraft saw more hints that watery jets may be shooting out into Space from an immense subsurface sea. The jets, tearing through cracks in the moon's icy crust, could lead back to a zone harboring living tidbits.