The last comms exchange prior to total comms/telemetry loss between Houston and Columbia was Houston acknowledging receipt of data on tire pressures. If this data indicates a pressure increase this could be due to the extreme temps on re-entry actually penetrating the heat-resistant "system" as a consequence of the integrity of the heat-resistant "system" being impaired on launch.
All total speculation at this stage.
NASA does, however, appear to be keeping the public informed this time round, after the semi-secrecy following Challenger. Let's all hope that once the data/telemetry that were subject to the contingency is married with the outcome of the NTSB/NASA investigation a cause can be established and new measures adopted for future manned missions.
There have been suggestions that an EVA was not possible, that the underside of Columbia was not able to be viewed and that there was no possibility of a dock with ISS. Let's hope future missions can incorporate some flexibility on such issues.
