Hypersonic Inflatable Aerodynamic Decelerators Technology Development Overview

Recent success of the Inflatable Reentry Vehicle Experiment (IRVE)-II flight experiment has generated
significant interest in Hypersonic Inflatable Aerodynamic Decelerator (HIAD) technology. This technology
development effort, initially pursued by NASA?s Fundamental Aerodynamics Program (FAP), includes both
flight and ground test elements. Due to budgetary constraints, the FAP development schedule was largely
serial, and precluded consideration of HIADs in near-term mission applications. Since the launch of IRVE-II,
a number of potential applications have been identified, along with the required technical development to
make such applications feasible. Through the studies, a common thread of desired accelerated
development has been identified. NASA?s Office of Chief Technologist (OCT) successfully advocated for
funds to initiate an accelerated HIAD development effort.

This paper provides an overview of a multi-year HIAD technology development effort that has been
proposed to OCT. There are four ground test elements. The Flexible Thermal Protection System (TPS)
element will investigate high temperature materials, coatings, and additives for use in the bladder,
insulator, and heat shield layers. The Inflatable Structures element will include manufacture and testing
(laboratory and wind tunnel) of articles up to 15 m in diameter. The Advanced Concepts element will
investigate alternate means of generating lift, G&C algorithms to utilize that lift, and advanced inflation
systems. The Mission Applications element will develop concepts (including payload interfaces) for missions
at multiple destinations.

Flight projects in the proposed development are to be conducted in parallel, rather than sequentially, in an
effort to compress the overall schedule. There are three flight test elements. IRVE-3, scheduled to launch in
Spring 2012, will experience an order of magnitude more heating than IRVE-II, and will demonstrate the
effectiveness of using a movable radial cg shift to produce a lift vector with HIAD. IRVE-4, proposed for
launch in 2013, will investigate controllability of a HIAD to improve targeting and reduced peak
deceleration. The Orbital Flight Test (OFT), proposed to launch in 2014, will demonstrate relevant scale in
relevant environments via a large-scale aeroshell (~8m) entering at orbital velocity (~7km/sec) with a
relevant payload mass (~2.5MT).