Sierra Space Drop Tests Ghost Hypersonic Decelerator

Sierra Space’s Ghost system recently completed drop tests in Florida.

Credit: Sierra Space

Sierra Space has begun initial drop tests of Ghost, a deployable decelerator designed to protect a pre-staged payload during reentry from storage in orbit to any location around the world within 90 min. of call-up.

Developed by Axelerator, Sierra’s newly launched innovations incubator group, the system forms part of the company’s plans to expand its defense technologies portfolio along with other ventures including Spectre, a satellite designed for precision rendezvous and proximity operations, and Sierra Black OS, an AI-enabled operating system for autonomous space operations.

Sierra’s vision is for the Ghost is to remain in standby mode on-orbit for up to five years with each spacecraft outfitted with pre-determined supplies such as a survival kit, an inflatable boat, rations and weaponry. Once activated the system is designed to re-orient the decelerator heat shield for re-entry while a deorbit motor slows the spacecraft to 7,000 m/sec.  (22,966 ft./sec.).

The thermal protection system, which Sierra says could “cloak” the payload during storage in orbit to conceal it from adversaries, will protect the payload from temperatures up to 2,000F during reentry. Once through the atmosphere, the shield will be discarded at a lower altitude to allow the payload to descend on a Joint Precision Airdrop System-like parafoil system to within 100 m of the target.

Drop tests were conducted at the Shuttle Landing Facility (SLF), Kennedy Space Center, Florida, on Feb 1, to evaluate the performance of the system over “the last mile” from an altitude of around 5,000 ft. Three drops were performed from a Sikorsky S-76C owned by Florida-based Operator Solutions beginning with a terminal drop with no parachute to assess the effect of the impact on the payload.

The second test article was dropped from 4,000 ft. and configured with a parachute that deployed at 2,000 ft. before landing successfully next to the SLF. The third test saw the shield portion separate from the spacecraft satellite bus before the payload descended on the parachute.

Guy Norris

Guy is a Senior Editor for Aviation Week, covering technology and propulsion. He is based in Colorado Springs.