Theoretically, it could have easily returned to Earth with the Space Shuttle, assuming another vehicle could rendezvous and transport it to LEO.

The Ascent State was 2.8 x 4.2 x 4.04m with a dry mass of 2150 kg.

The Shuttle's cargo bay was 18 x 4.6 x 4.6m (at least...can't find a depth weirdly) with a return-to-Earth payload capacity of 14,400 kg.