Sierra Nevada Corporation announced that two Contractor-Owned Contractor-Operated ATHENA-S jets finished testing and are now operational in support of the U.S. Army’s Aerial-ISR mission. Sierra Nevada Corporation (SNC) has announced on Apr. 15, 2026, that both contractor and government testing of the Army Theater level High Altitude Expeditionary Next Airborne ISR-Signals Intelligence (ATHENA-S)…