THE FACTORS that will drive the answer are still unknown, and the biggest uncertainty remains in what recommendations the Columbia Accident Investigation Board will make as requirements for approving a new shuttle launch. But NASA has anticipated the sorts of things that will be necessary. They include reduced foam shedding at launch, enhanced inspection and repair of the fragile thermal protection system in flight, and a more responsive management and safety system. Current plans call for the next flight, on Atlantis, to carry supplies and possibly a replacement crew to the international space station. Veteran pilots Eileen Collins and Jim Kelly will fly the shuttle, with two veteran mission specialists also aboard. OCTOBER? NO WAY • Anatomy of a disaster • Tragedy's timeline • Space shuttle history • The aging shuttle fleet • Images from the tragedy • Space exploration setbacks MSNBC.com has obtained a number of internal NASA planning documents that address this schedule question. The most optimistic “planning date” for next launch is Oct. 1, which nobody believes. A more serious schedule, published by the Flight Design and Requirements Office of the space shuttle program, is “no earlier than Dec. 18.” Other high-level briefings have mentioned dates between April and June of 2004. During a May 23 internal briefing, astronaut James Halsell, the NASA official in charge of coordinating the “return to flight” effort, reported that his team was “moving aggressively and proactively toward near-term return to flight” with a goal of resuming shuttle missions as soon as safely as possible to “mitigate ISS risks” — that is, to rescue the space station. According to Halsell, a return to flight by Dec. 3 was “not impossible,” but he added several caveats: “Environments validation,” a study of the true conditions under which the shuttle will have to operate, “will not be completed until Jan-Mar 2004.” Redesign of the external fuel tank’s liquid hydrogen “Intertank Flange” hardware, if required, “could push RTF [return to flight] to Apr 2004.” If NASA has to unfasten Atlantis’s reinforced carbon-carbon leading-edge wing panels for detailed inspection and refurbishment, this “could push RTF to Jan-Feb 2004.”