Stratospheric airship reaches near-space altitude during demonstration flight

A team led by Southwest Research Institute (SwRI) successfully demonstrated powered flight of the HiSentinel stratospheric airship at an altitude of 74,000 feet. The development team of Aerostar International, the Air Force Research Laboratory (AFRL) and SwRI launched the airship from Roswell, N.M., for a five-hour technology demonstration flight. The 146-foot-long airship carried a 60-pound equipment pod and propulsion system when it became only the second airship in history to achieve powered flight in the stratosphere.

Designed for launch from remote sites, these airships will not require large hangars or special facilities. Unlike most stratospheric airship concepts, HiSentinel is launched flaccid with the hull only partially inflated with helium. As the airship rises, the helium expands until it completely inflates the hull to the rigid aerodynamic shape required for operation.

Sponsored by the U.S. Army Space and Missile Defense Command, the flight was the culmination of a six-month preparation effort.

"There are a number of stratospheric airship programs being promoted around the world, but this is the first of these programs to successfully fly a real airship in near-space," says William Perry, assistant director of Space Systems in the SwRI Space Science and Engineering Division.

SwRI designed the airship and provided the telemetry, flight control, power and propulsion systems. Aerostar International fabricated the hull and participated in the integration and test flight. AFRL developed the innovative launch system, provided facilities, and supported the launch and recovery. Each of the four organizations contributed funding, manpower, equipment and facilities for the collaborative effort.

HiSentinel is the first airship developed under the Composite Hull High Altitude Powered Platform (CHHAPP) program. CHHAPP is a spiral development program for a family of long-endurance autonomous solar-electric, stratospheric airships. These low-cost systems will be capable of lifting small- to medium-payloads (20 to 200 pounds) to near-space altitudes for durations of longer than 30 days for communications, military and science applications.

The project, titled HiSentinel, is focused on developing small near-space airships for inexpensive tactical communications and Intelligence Surveillance and Reconnaissance (ISR) applications. The relatively inexpensive nature of the Hi Sentinel system will allow several test flights per year to take place, Raven President and CEO Ronald M. Moquist said. Future test flights will include multi-day missions with solar power and demonstration of the SwRI autonomous station-keeping autopilot. Once operational, the system may be deployable by local commanders in theater operations. HiSentinel is part of Aerostar's ongoing technology roadmap in developing inexpensive stratospheric LTA (Lighter Than Air) platforms for military and commercial use.