Rank 1 opens the NASA Heritage catalog with Explorer 1 — the 13.37 kg JPL payload that ended the Army–Navy satellite rivalry and proved the United States could place science in orbit after Sputnik 1. Launched 31 January 1958 atop a Jupiter-C / Juno I from Cape Canaveral LC-26, the spacecraft carried a Geiger counter and micrometeorite detector that revealed the Van Allen radiation belts — a discovery that reframed human spaceflight as a physics problem, not merely a propaganda race. William Pickering's JPL team and James Van Allen's instrument package turned a slim four-antenna satellite into the founding specimen of US space science. Heritage Collector renders the stippled hero, vertical title spine, and JPL footer exactly as the master PNG dictates.