Rank 12 documents Mars Pathfinder — the 264 kg lander and 11.5 kg Sojourner rover that touched Ares Vallis on 4 July 1997 after an innovative airbag landing demonstration. Tony Spear's Discovery Program team at JPL delivered the first Mars rover, the first airbag bounce landing success, and the first mission to drive public web traffic past every prior NASA event. Sojourner deployed the sol after landing and operated 83 sols, using APXS rock composition analysis and Imager for Mars panoramas that returned the rocky valley views defining 1990s Mars exploration. The low-cost demo paved the way for Spirit, Opportunity, and the MER era. Heritage Collector renders the tetrahedral lander hero, Sojourner at ramp foot, and ghost 1997 numeral exactly as the master PNG dictates.