Keith Peterson

Adaptive Deployable Entry and Placement Technology (ADEPT): A Feasibility Study for Human Missions to Mars

The present paper describes an innovative, semi-rigid, mechanically deployable hypersonic decelerator system for human missions to Mars. The approach taken in the present work builds upon previous architecture studies performed at NASA, and uses those findings as the foundation to perform analysis and trade studies. The broad objectives of the present work are: (i) to assess the viability of the concept for a heavy mass (landed mass ≈40 mT) Mars mission through system architecture studies; (ii) to contrast it with system studies previously performed by NASA; and (iii) to make the case for a Transformable Entry System Technology. The mechanically deployable concept at the heart of the proposed transformable architecture is akin to an umbrella, which in a stowed configuration meets launch requirements by conforming to the payload envelope in the launch shroud, and when deployed in earth orbit forms a large aerosurface designed to provide the necessary aerodynamic forces upon entry into the Martian atmosphere. The aerosurface is a thin skin draped over high-strength ribs; the thin skin or fabric with flexible material serves as the thermal protection system, and the ribs serve as the structure. A four-bar linkage mechanism allows for a reorientation of the aerosurface during aerocapture or during the entry and descent phases of atmospheric flight, thus providing a capability to navigate and control the vehicle and make possible precision landing. The actuators and mechanisms that are used to deploy the aerosurface are multi-functional in that they also allow for reorienting the

Small Probe Reentry Investigation for TPS Engineering (SPRITE)

Small Probe Reentry Investigation for TPS Engineering (SPRITE) is a novel concept for a comparatively low-cost means of certifying thermal protection system (TPS) materials for spaceflight. By developing a fully instrumented small-scale test platform that can be tested both in arc-jet facilities and in flight, SPRITE promises to improve the ground-to-flight traceability of TPS qualification programs by implementing the NASA “test-like-you-fly” policy. This paper discusses the design and manufacture of the proof-of-concept SPRITE test articles, development and capabilities of the SPRITE flight-like data acquisition system, and fidelity of the design tools used in the effort. With the successful completion of this stage of the SPRITE project, the next test article to be built will have a hemispherical backshell as originally designed for flight stability. Unlike the initial proof-of-concept probes, TPS for the next test article will be scaled according to current margins policies for arc-jet testing at relevant flight-like aerothermal environments. At the conclusion of the ground test campaign, SPRITE probes will be ready for flight testing and, ultimately, acceptance into future mission planning where they will contribute to more affordable access to space for both large and small science payloads.

Thermal and Structural Performance of Woven Carbon Cloth For Adaptive Deployable Entry and Placement Technology

Arcjet testing and analysis of a three-dimensional (3D) woven carbon fabric has shown that it can be used as a thermal protection system and as a load bearing structural component for a low ballistic coefficient hypersonic decelerator called ADEPT (Adaptive Deployable Entry and Placement Technology). Results of arcjet tests proved that the 3D woven carbon fabric can withstand flight-like heating while under flight-like biaxial mechanical loads representative of those encountered during shallow entry flight path angles into the atmosphere of Venus. Importantly, the arcjet test results have been used to extend a preliminary material thermal response model based on previous testing of the same 3D woven carbon fabric under uni-axial mechanical loading.