support needed to offset arcjet costs. Willcockson also noted that the NASA roadmap does not mention in-flight instrumentation use, but that this was done on Pathfinder and is being done on MSL because funding was available. After Willcockson’s presentation, a workshop participant provided an additional comment that shock loads can force design changes (e.g., the use of RCC instead of tiles for attach points on the space shuttle), and that testing and modeling need to go together.
Chris Mangun (CU Aerospace) next provided a presentation with a materials perspective on the NASA roadmap. For rigid ablative TPS, he noted that PICA is the current state of the art, but posed the question on whether it will work for the next generation. Mangun noted that for reentry with high heating rates, the thermosetting resin must char, and outgassing of resin is advantageous, as it thickens the boundary layer and reduces heat flux. He listed several desired TPS properties, including low thermal conductivity, high heat of ablation, mechanically tough— not brittle (i.e., resin must adhere well to reinforcement)— and monolithic construction (i.e., avoiding tiles). He provided some discussion on aromatic thermosetting copolyesters, and noted several benefits and potential future applications of this material. Another topic that Mangun commented on was the use of AlB2 as a planar reinforcement for metal matrix composites (MMCs). Regarding self-healing materials for applications such as micrometeoroid and orbital debris protection, structural recovery, and self-sealing cryotanks, Mangun noted that dual-microcapsule systems in composites are one option; he also mentioned that new microvascular approaches can continuously deliver healing agents. (Note that a microvascular network in a structural composite can also introduce dynamic, reconfigurable functionality, such as damage sensing, thermal management, and radiation protection.) Mangun concluded his presentation noting that it may be possible to accelerate some technologies (e.g., multifunctional TPS, structurally integrated TPS, and self-repairing composites).
Public Comment and Discussion Session
The following are views expressed during the public comment and discussion session by either presenters, members of the panel, or others in attendance. (Note that due to an early end time for the last day of the workshop, there was limited time available for the public discussion period.)
• Roadmap funding assumptions. A participant asked the NASA team what the funding assumptions were, as the roadmap lists timeframes to specific TRL numbers for some of the technologies. The NASA team responded that there was no guidance on this, but in general they asked their staff to develop the details of each technology development assuming a “reasonable” funding profile.
• Importance of dual-use technologies. One workshop attendee posed the question on how much importance NASA puts on dual-use of the technologies, i.e., the applicability for a technology to benefit others outside NASA. The NASA team responded that while they are always looking for potential spinoffs, that will not drive the development of a specific technology.
Jamshid, A., Samareh, J.A., and Komar, D.A. 2011. Parametric mass modeling for Mars entry, descent and landing system analysis study. AIAA Paper 2011-1038. 49th AIAA Aerospace Sciences Meeting, Orlando, January 4-7, 2011. American Institute of Aeronautics and Astronautics, Reston, Va.
McGuire, M.K., Arnold, J.O., Covington, M.A., and Dupzyk, I.C. 2011. Flexible ablative thermal protection sizing on inflatable aerodynamic decelerator for human Mars entry descent and landing. AIAA Paper 2011-344. 49th AIAA Aerospace Sciences Meeting, Orlando, January 4-7, 2011. American Institute of Aeronautics and Astronautics, Reston, Va.
Venkatapathy, E. 2009a. Thermal Protection System Technologies for Enabling Future Sample Return Missions. White paper submitted to the Planetary Science Decadal Survey, National Research Council, Washington, D.C.
Venkatapathy, E. 2009b. Thermal Protection System Technologies for Enabling Future Outer Planet Missions. White paper submitted to the Planetary Science Decadal Survey, National Research Council, Washington, D.C.