SAMPE Journal - July/August 2012 - (Page 40)

Feature Article Composite Payload Fairing Structural Architecture Assessment and Selection Thomas M. Krivanek NASA Glenn Research Center, Cleveland, OH Bryan C. Yount NASA Ames Research Center, Moffett Field, CA Abstract This paper provides a summary of the structural architecture assessments conducted and a recommendation for an affordable high performance composite structural concept to use on the next generation heavy-lift launch vehicle, the space launch system (SLS). The structural concepts element of the advanced composites technology (ACT) project and its follow-on the lightweight spacecraft structures and materials (LSSM) project, was tasked with evaluating a number of composite construction technologies for specific Ares V components: the payload shroud, the interstage, and the core stage intertank. Team studies strived to address the structural challenges, risks and needs for each of these vehicle components. Building on the work from ACT and LSSM, the composites for exploration (CoEx) project is focused on demonstrating composite technologies for a payload fairing for SLS. This paper documents the evaluation and down selection of composite construction technologies and evolution to the SLS payload fairing. Development of the evaluation criteria (also referred to as figures of merit or FOMs), their relative importance, and association to vehicle requirements are presented. A summary of the evaluation results and a recommendation of the composite concept to baseline in the composites for exploration (CoEx) project are presented. The recommendation for the SLS fairing is a honeycomb sandwich architecture based primarily on affordability and performance with two promising alternatives, hat stiffened and fiber reinforced foam (FRF) identified for eventual program block upgrade. Introduction The Advanced Composites Technologies (ACT) and follow on Lightweight Spacecraft Materials and Manufacturing (LSSM) Projects were implemented to help enable the Constellation Program to support a manned lunar mission via mass reduction of vehicle dry structures through the use of composite materials1. The ACT project was formulated to advance the technology readiness level (TRL) of large scale composite structures from TRL 3-4 (Proof of concept / validated in lab environment) to TRL 6. (System/subsystem demonstrated in a relevant environment)2. The objective of the structural concepts studies was to identify, optimize, and evaluate composite concepts for use as dry structures on the Ares V Heavy Lift Launch Vehicle. The results from these studies are applicable to the new space launch system (SLS) Heavy Lift Launch Vehicle (Figure 1). An agency-wide team with members from Ames Research Center, Glenn Research Center, Goddard Space Flight Center, Kennedy Space Center, Langley Research Center, and Marshall Space Flight Center was assembled to perform these studies. The Structural Concepts Team identified eight composite construction technologies that met the initial feasibility ground rule of having a TRL of three or higher. These construction technologies (or concepts) were then analyzed and sized for use on the payload shroud per the project requirements and ground rules. (The payload fairing element was referred to as “shroud” during the Ares V project). The concepts were then rated with respect to the Figures of Merit (FOMs). Key figures of merit included mass, development risk (due to TRL maturity), damage tolerance, cost, acoustic transmissibility, thermal tolerance, joining, and inspectability. Weighting factors were applied to each FOM based on their relative importance to the project, and a modified analytical hierarchy process (AHP) was used to rank the proposed composite construction technologies. This process was used to determine the top two candidate construction concepts to be recommended for possible use. Payload Fairing Requirements and Configuration Requirements for the Structural Concept Studies were extracted from the Ares V vehicle requirements. A total of 29 requirements were identified, but many of these have negligible effect on the structural concept studies. The remaining requirements could be identified as sub-sets of the following five categories. • Payload protection and environmental control (Ground, launch and flight ops) • Payload access (During integration and on-pad) • Structural integrity (For all ground, launch and flight environments – includes inertial, aerodynamic, vibration, thermal and acoustic loads) • Separation from launch vehicle (As commanded) • System Telemetry (Including Structural Health Monitoring (SHM)) Figure 1. SLS heavy lift launch vehicle. 40 SAMPE Journal, Volume 48, No. 4, July/August 2012

Table of Contents for the Digital Edition of SAMPE Journal - July/August 2012

SAMPE Journal - July/August 2012
Table of Contents
President’s Message
Technical Director’s Corner
Development of New Lightweight Hybrid Sandwich Cores using FDM Technology
Corporate Partners
Europe News & Views
SAMPE Europe’s SETEC 2012, Lucerne
SAMPE Journal Editorial Calender
Welcome SAMPE’s Newest Members
Materials & Products
Perspectives
Perspectives–The Art of a Well-Crafted BHAG
Out-of-Autoclave Sandwich Structure: Processing Study
SAMPE LinkedIn Communities
SAMPE Proceedings
SAMPE 2013|Long Beach Call for Papers
SAMPE Tech 2012|Charleston, SC
Industry News
Composite Payload Fairing Structural Architecture Assessment and Selection
SAMPE 2012|Baltimore-A Review
SAMPE 2012|Baltimore Photo Gallery
The SAMPE Foundation
Advertiser’s Index
Resource Center
SAMPE Membership Application
SAMPE Books & CD’s Order Form
Industry Events Calendar
Chapter Meetings Dates and Contacts

SAMPE Journal - July/August 2012