It is believed to be this or a similar craft -
Airbus’ Zephyr S is the world’s leading solar-electric UAV that is conquering the stratosphere.
The new variant is intended for a variety of military, security and civil missions, including maritime surveillance, border patrol, intelligence, reconnaissance, navigation, satellite-like communications, missile detection, environmental surveillance, signals intelligence (SIGINT), in-theatre C4ISTAR relay, continuous photo capturing, and humanitarian and disaster relief.
The first production aircraft performed its maiden flight in July 2018 and achieved a flight endurance record of nearly 25 days. The aircraft is set to perform additional flights from the Wyndham airfield in Western Australia during the second half of 2018.
https://www.airforce-technology.com/projects/zephyr-s-high-altitude-pseudo-satellite-haps/