Eight options to increase the orbiter's ability to withstand minor debris damage are being evaluated. These include: wing leading-edge redesign; tougher lower-surface tiles; upgraded thermal barrier materials on the landing-gear and ET doors; redesign of carrier panels and attachments; TPS impact sensors; replacement of certain upper-surface tiles with tougher tiles; a high-emittance coating on vertical-tail insulation blankets to expand low angle-of-attack re-entry trajectory limits; and development of a more debris-tolerant RCC for the nose cone, chin panel and wing leading-edge. Implementation plans are to be presented by December.
NASA is pursuing techniques for non-destructive inspection of the RCC without removing it from the vehicle, with flash thermography and ultrasound showing most promise. For RTF, components will be removed from the orbiters and returned to the vendor for inspection, combined with destructive evaluation of selected attachment hardware. RCC inspection on Atlantis is to be completed this month.
Source: Flight International
