Cosmic Background Explorer
The Cosmic Background Explorer (COBE KOH-bee), also referred to as Explorer 66, was a NASA satellite dedicated to cosmology, which operated from 1989 to 1993. Its goals were to investigate the cosmic microwave background radiation (CMB or CMBR) of the universe and provide measurements that would help shape the understanding of the cosmos.
Source: Wikipedia — Cosmic Background Explorer (CC BY-SA 4.0)