From there, modules made Mir bigger and more capable. On April 12, 1987, the Kvant-1 docked to the core module, adding instruments to measure electromagnetic spectra and x-ray emissions of distant galaxies, quasars, and neutron stars to the growing station. This module also housed an attitude control system using gyrodines rather than propellant-fed reaction controls, making the whole station far more maneuverable. A second Kvant module, Kvant-2, brought a second set of gyrodines to Mir on December 6, 1989, as well as an airlock for simpler spacewalks, a jetpack akin to NASA’s Manned Maneuvering Unit, and a new life-support system capable of recycling water and generating breathable oxygen. With this module, the station started becoming truly self-reliant, or at least more than it had been to this point.