PAL Ramps to be removed from all ETs

by Chris Bergin

Multiple sources have noted that a decision has been made to remove all Protuberance Air Loads (PAL) Ramps from all current and future External Tanks (ET) – a process likely to end an opportunity to launch Atlantis on STS-121 this year.

Stemming from a management meeting at the Michould Assembly Facility (MAF) – where the ETs are constructed before shipping to the Kennedy Space Center (KSC) – sources note it was determined that the best solution to eliminating foam liberation concerns is to remove the PAL Ramps.

While Bill Gerstenmaier, the space agency official leading the investigation into the foam loss, noted that there is no immediate resolution to the issues of ET foam liberation, the process of removing the PAL Ramps from all current ETs required for a resumption of flight – namely ET-120 (with Atlantis for STS-121) and ET-118 (currently set to be with Discovery in support of STS-121 on STS-301) could take around six months to turnaround.

While the September window – from September 22 through September 26 – has not officially been called off, Gerstenmaier did note there’s not much chance of Atlantis making that window.

“We will probably not make the September launch window,” he said. Short windows in November, December and January exist, but the next main opportunity for a good length window is in March, 2006.

ET-119 is already slated for returning to MAF for modifications, with ET-118 set to follow soon after. ET-120 will remain with Atlantis for an APU Hot Fire test on the launch pad later this month – although that is yet to be confirmed by NASA or the United Space Alliance (USA).

With a further confirmation that ET-121 that flew with Discovery on STS-114 had received a repair in the area of the PAL Ramp that liberated foam during assent, it is now believed that MAF have been excluded from blame in the way the repair was carried out – in reference to the foam shedding.

“That alone probably wouldn’t be enough to cause the foam loss that we saw,” he said. “There’s probably another underlying problem in there.”

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