A tale of two Shuttles (part two)

Challenger’s engines ignite for a Flight Readiness Firing test. The second FRF took place on Jan. 25, 1983. Twenty years later Columbia was in orbit on a 16-day flight.

*****

It’s January 25, 2003.  This is Flight Day 10 aboard Columbia and the STS-107 science mission.  The smorgasbord of experiments continue in the double Spacehab module, the crew working in two shifts around the clock.  This day, life sciences experiments, with bone cells and bacterial growth, physics experiments in thermal heating and surface tension, earth observations with images of dust plumes off the coast of Africa and storms over Australia.  

Flight Day 10 also marks the day after the Mission Management Team overseeing the flight determines that a debris strike on launch poses no risk to the flight, shutting off efforts to gain photographs of the damage by military spy systems.

Within two hours of launch on January 16, a photo working group reviewing tracking video of Columbia’s ascent, showed little.  But the next day higher resolution film showed something dramatic:   A suitcase-size piece of debris striking the left wing 81.9 sec. into flight.  The debris appeared to be foam insulation from an aerodynamic “ramp” on the bipod struts attaching the nose of the Orbiter to the big External Tank.  The piece impacted the wing’s unseen underside between Reinforced Carbon-Carbon (RCC) panels 5 and 9.  The RCC panels form the hardened leading edge of the wings.  The impact sent a shower of small particles trailing the wing.  The team’s main concerned centered on the much more fragile heat protection tiles covering the wing’s surface than the RCC panels, believed to be impervious to damage.  Alarmed, they sent in a request for NASA to ask the Air Force to photograph the Orbiter with spy telescopes.  Both ground-based and space-based military “assets” could produce high resolution images. The DOD began preparing to do so.

Mark that as request number one.

A Debris Assessment Team was formed and after the long Martin Luther King holiday weekend, first met on Tuesday, Flight Day 6.  They made a separate request for DOD photos to the Engineering Management Directorate at the Johnson Space Center, Houston.  

Mark that as request number two.  The request will denied as not needed, with the belief the damage to tiles couldn’t be that severe, based on the history of prior debris impacts.

The United Space Alliance, the consortium that processes the Shuttle for flight, also requested Air Force imaging.  Mark this as request number three.  The Air Force Support Officer at Johnson Space Center begins implementing the request, willing and eager to help.  But this request was canceled by NASA managers — as not having come through the proper chain of command.  

The Debris Assessment Team worked to verify this theory using the only means they had:  A computer program called “Crater” designed to model the effects of small impacts.  It was not designed to analyze impacts of this size, but was considered a “conservative” tool, as it has always overestimated the effects of strikes, giving confidence in the results.  

For six days, the team analyzed the data, and on Flight Day 9, reported to the Mission Evaluation Room, which oversaw engineering aspects of the flight, that, indeed, some localized heating might occur due to damaged tiles, but no threat to flight safety existed.  The result were reported verbally to Mission Management Team, the top level overseeing the flight.  That was the end of it, except for backchannel chatter among alarmed engineers.

That same day, the debris strike was reported for the first time to Mission Commander Rick Husband in an email, including a short video clip of the impact.  The only reason he was informed was because the crew may be asked about it in an in-flight press conference later in the day.  (The question never was asked.)

The email stated “Experts have reviewed the high speed photography and there is no concern for RCC or tile damage.  We have seen this same phenomenon on several other flights and there is absolutely no concern for entry.”  Reentry on February 1 was to be normal.  

The science flight continued, 80 experiments in all.  On January 28, the crew enjoyed has half a day off, and they paid tribute to the lost crews of Apollo 1 (January 27, 1967) and Challenger (January 28, 1986) with a moment of silence.

***

It’s January 25, 1983, and the brand-new Shuttle, Challenger, on Pad 39-A comes to life.  Its Main Engines fire not for launch, but for a second Flight Readiness Firing needed to trace the origin of high levels of hydrogen monitored in the engine compartment during the first FRF on December.  The three engines fire for 23 seconds, and the hydrogen leak is traced to Engine #1 in the hight pressure system.  The maiden launch of Challenger on STS-6, scheduled for late February, will have to be delayed by several weeks as the engine is replace.   Then as the replacement is being installed in early February, an oxygen leak will be discovered within it.  Yet another engine will be shipped, the launch then aiming for March 19 or 20.   

On February 26, a hydrogen leak will be uncovered in Main Engine #2.  And by February 28, the same type of leak will be discovered in Main Engine #3.   

There must be some common flaw, even though the Shuttle has flown five times.  The past cannot predict future performance — that should be the lesson.

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