Low-Earth Orbit Flight Test of an Inflatable Decelerator (LOFTID)

NASA’s Low-Earth Orbit Flight Test of an Inflatable Decelerator (LOFTID), dedicated to the memory of Bernard Kutter – a manager of advanced programs at United Launch Alliance (ULA) who championed lower-cost access to space and technologies to make that a reality – is a partnership between NASA’s Space Technology Mission Directorate and ULA to demonstrate an inflatable aerodynamic decelerator, or aeroshell, technology that could one day help land humans on Mars.

Since NASA’s inception in 1958, the agency has relied heavily on rigid aeroshells (a protective shell composed of a heat shield and a back shell), parachutes, and retro-propulsion (rockets) to decelerate people, vehicles, and hardware during orbital entry, descent, and landing operations. The LOFTID demonstration is poised to revolutionize the way NASA and industry deliver payloads to planetary destinations with atmospheres.

After more than a decade of development of Hypersonic Inflatable Aerodynamic Decelerator (HIAD) technology, including two suborbital flight tests, the LOFTID orbital flight test is the next step. This return from orbit demonstration provides an entry environment relevant to many potential applications, paving the way for its use on future missions. The LOFTID re-entry vehicle, at 19.7 feet (6 meters) diameter, will be the largest blunt body aeroshell to ever go through atmospheric entry.

When a spacecraft enters an atmosphere, aerodynamic forces – like drag – act upon it, slowing it down and converting its kinetic energy into heat. Using atmospheric drag typically is the most mass-efficient method to slow down a spacecraft. Since HIAD technology is larger than traditional aeroshells, it creates more drag and starts the deceleration process in the upper reaches of the atmosphere, allowing not only heavier payloads, but also landing at higher altitudes. It could additionally be used to bring an unprecedented amount of mass back from low-Earth orbit, including items from the International Space Station. Another significant potential benefit is enabling the recovery of rocket assets for reuse which can reduce the overall cost of access to space.

The HIAD design consists of an inflatable structure that maintains its shape against the drag forces, and a protective flexible thermal protection system that withstands the heat of reentry. The inflatable structure is constructed with a stack of pressurized concentric rings, or tori, that are strapped together to form an exceptionally strong blunt cone-shaped structure.

The rings are made from braided synthetic fibers that are, by weight, 10 times stronger than steel. A flexible thermal protection system insulates the rings from the searing heat of atmospheric entry; LOFTID can withstand temperatures in excess of 2900°F (1600°C). It’s constructed with three layers: an exterior ceramic fiber cloth layer to maintain integrity of the surface, a middle layer of insulators to inhibit heat transmission, and an interior layer that prevents hot gas from reaching the inflatable structure. The flexible thermal protection system is also foldable, packable, deployable, and tailorable. Because it is flexible, it takes up less room in the rocket and allows the design to be scalable.