Memos Show NASA Managers Debated Astronauts’ Safety

This weekend’s shuttle scrub over those balky ECO sensors may seem arcane, but internal NASA e-mails show that NASA managers "struggled with the potential risk to astronauts’ lives" in deciding what to do about them.  Today, NASA’s working on a plan to figure out just what’s wrong with the fuel sensors, so they can launch right after the first of the year. Two full-time space reporters, Chris Bergin of NASASpaceFlight.com and Craig Covault of Aviation Week & Space Technology, report that after the launch was first scrubbed last Thursday, a debate broke out among shuttle managers. The problem with ECO sensors — short for Engine Cut-Off — has gone on since 2005, and bedeviled four of the last seven launches.  Four sensors for liquid hydrogen are mounted inside the shuttle’s orange external fuel tank, and protect against the shuttle’s main engines continuing to fire if the tank has run dry.  High-powered pumps could theoretically fly apart in that case, with potentially disastrous consequences. But Wayne Hale, the head of the shuttle program, is quoted by Bergin in a memo Friday as wondering if the system has ever really worked — and if "it is now time to consider whether we can live without it."  He gets emphatic disagreement from William McArthur, an astronaut who has flown four flights and now works on shuttle safety: "’Most at JSC [the Johnson Space Center in Houston] heard direction today to ‘find rationale for flight’ versus ‘is the risk of flying without the ECO sensor system acceptable?’. To me, this seems to be a huge leap." "We fix things that don’t work," he adds. It’s worth reading the full stories to get the context.  Chris Bergin’s version is HERE; Craig Covault’s is HERE. There’s a lot of jargon in the e-mails, and the bottom line is that engineers are still working on the sensors.  But the e-mails provide a window into the thinking of some NASA people — who clearly take their responsibilities seriously — wrestling with a very frustrating problem.
================== Update, 4:00 p.m. Wayne Hale, in a conference call with reporters, says engineers will try filling the external tank with fuel in a test next Tuesday.  There will be extra instrumentation, so that if, as he expects, the ECO sensor system acts up again, they will be able to isolate the problem.  They’re working toward a launch window that begins on January 2.