Zephyr 8 Comes Down After 64 Days in the Stratosphere

The idea that you could launch an unmanned aircraft and it could stay aloft for two months, unrefueled, as it roams between North and South America on a 30,000-mile sortie, is bananas.

But it just happened.

The Airbus Zephyr series is an ultra-lightweight (165 pounds) long-winged (82-foot wingspan, roughly the same as a PBY Catalina) that can still lift an OPAZ camera system capable of taking 18cm high-resolution images from 65,000 feet in the air and delivering them BLOS in real-time– covering a 20 km x 30 km swath at a time.

Now that’s persistent ISR.

HAPS Zephyr in preparation before take-off

Airbus feels the aircraft has serious uses for maritime security, convoy protection, land/coastal border protection, and SIGINT, and they aren’t wrong. 

One of the prototypes, Zephyr 8, just burned in after spending a record 64 days in the air. This smashed the aircraft’s 2018 test flight of 25 days, 23 hours, and 57 minutes endurance, without refueling.

From APNT/Space CFT at Redstone Arsenal:

HUNTSVILLE, Ala. – The Assured Positioning, Navigation and Timing/Space (APNT/Space) Cross-Functional Team (CFT) has concluded a 64-day stratospheric flight demonstration utilizing Airbus’s Zephyr 8 ultra-long endurance solar-powered unmanned air system (UAS).

Launched from Yuma Proving Ground (YPG) on June 15, the Zephyr 8 UAS ascended to over 60,000 feet into the stratosphere before executing its flight plan over the southern portion of the United States, into the Gulf of Mexico, and over South America. Once returning to airspace over YPG, the team conducted multiple assessments.

On August 18 around 2100 hours PDT, the prototype aircraft’s flight campaign ended when the Zephyr 8 UAS encountered events that led to its unexpected termination over YPG. These events are under investigation. No injuries or risks to personnel or other aircraft resulted from this incident. Further information will be released following the investigation.

“Our team is working hard to gather and analyze important data following the unexpected termination of this flight,” said Michael Monteleone, Director of the APNT/Space CFT. “Despite this event, the Army and its partners have gleaned invaluable data and increased knowledge on the endurance, efficiency, and station-keeping abilities of high-altitude UAS platforms. That knowledge will allow us to continue to advance requirements for reliable, modernized stratospheric capabilities to our Soldiers.”

This flight marked a number of firsts for Zephyr 8, including its departure from U.S. airspace, flight over water, flight in international airspace, data collection and direct downlink while outside of U.S. airspace, the longest continuous duration (7 days) utilizing satellite communications, and the demonstration of resilient satellite command and control from three different locations – Huntsville, AL; Yuma, AZ; and Farnborough, UK.

During this flight, Zephyr 8 more than doubled the previous UAS endurance record, just under 26 days, and flew in excess of 30,000 nautical miles – more than one lap around the Earth. The 1,500 flight hours beat all known unmanned aircraft endurance records, marking significant capability and informing future mission requirements.

This experimentation successfully demonstrated Zephyr’s energy storage capacity, flight endurance, station-keeping, and agile positioning abilities. Given the amount of data that was generated during the 64-day flight and the time required to analyze it, as well as the need to investigate the events that led to the termination, further flight demonstrations have been postponed until 2023.

This 64-day test flight was performed in conjunction with government and industry partners who support experimentation that continues to inform Army requirements.

One thing I wonder about is the type’s susceptibility to operating in a non-permissive environment. What is the radar signature of a “pseudo satellite” cruising around at low speed and extreme altitude and how easy would it be to shoot it down? 

Even older Warsaw Pact high-performance interceptors such as the MiG-25 Foxbat have an operational ceiling above 80,000 feet and today’s better fighters such as the Sukhoi Su-35 Flanker-E have a published operational ceiling of 59,000 feet but I’d bet could make it to 65K if they had to in a wartime scenario.

The RP-25 Smerch-A/Foxfire radar had an impressive )for the time) power rating of 600kw that reportedly could cook a rabbit alive at 2 meters. But could it pick up a Zephyr?

Vietnam-era SAMs such as the SA-2 can reach 60,000 feet but would be largely unguided at that height although that didn’t stop them from getting lucky if used in quantity– CIA pilot Gary Powers found that out in his U-2 over Russia in 1960 despite that aircraft’s high altitude (rumored to be about 68,000 feet when shot down by a volley of 17 SA-2s).

Could an S-400 SAM system, if cued by an AWACS, make a hit on Zephyr? We may find out…

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