NASA says it is making significant progress towards understanding the debris environment and materials characteristics of the Space Shuttle orbiter and its thermal protection system (TPS), as part of its return-to-flight (RTF)work. Shuttle flights have been suspended since the loss of Columbia during re-entry in 2003, writes Tim Furniss.
NASA can now better target critical areas for hardening before RTF and make significant improvements to the external tank to reduce debris being shed during launch. It is developing repair techniques and materials for the TPS, particularly acreage tiles and cracks and small holes in reinforced carbon-carbon.
NASA admits that attempts to develop a rigid over-wrap for the wing leading-edge that could be used to cover large holes - such as the one that caused the loss of Columbia - have "encountered significant challenges". It says it has "deferred development of the rigid wrap" and is "pursuing a broader effort to identify more flexible alternatives for repairing holes in the wings".
The first two RTFs will have a contingency crew survival capability, enabling the Shuttle to dock with the International Space Station while another orbiter is sent to rescue the crew.
Source: Flight International
