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At one point, freon was a component in the external fuel tank insulation. NASA was in the process of changing the recipe to be more environmentally friendly whe

by csixty4 11y ago

At one point, freon was a component in the external fuel tank insulation. NASA was in the process of changing the recipe to be more environmentally friendly when the Columbia accident happened. The tank on STS-107 was built with the newer foam, but the "bipod" part which the foam fell off of was coated in the older foam. That didn't stop Rush Limbaugh et al from blaming environmentalists.

InclinedPlane 11y ago
There was no shortage of foam/ice strikes with the older foam either. STS-27 in 1988 sustained very severe tile damage from a foam strike during liftoff (around 700 tiles were damaged, including some which were completely destroyed), which resulted in partial melting of some of the airframe components during re-entry. They lucked out in that the strike was on the more durable part of the vehicle, if it had hit the leading edge as happened to Columbia the vehicle likely would have met the same fate.
- mikeash 11y ago
  That's crazy. And yet it looks like nothing was done afterwards to prevent it from happening again? What was wrong with them over there?
  - InclinedPlane 11y ago
    It didn't destroy the vehicle so the importance of it was downplayed. It was thought, even up to the time of the Columbia disaster, that the reinforced carbon-carbon composites on the wing leading edges were too strong to take damage from a foam/ice strike. And there were contingencies in place for foam damage, though the system was overall resilient enough to take a fair bit of damage without causing a loss of the vehicle during re-entry. So to some extent they thought they had their bases covered, though in reality that was just a fantasy. The reality was that it was extremely difficult to assess any damage to the thermal protective system while on orbit, there weren't actually any feasible options for repairs of major damage, there weren't proper contingencies for a rescue operation except when the orbiter visited the station (and then only just barely), and the wing leading edge material turned out to be far more brittle than had been modeled. The whole history of the Shuttle system is a history of dodging disaster left and right and then hitting it after leaning too heavily on luck for too long. The very first flight of the Shuttle involved an "anomaly" during launch which the crew said would have resulted in them attempting to ditch if they had known about it during liftoff. On the 9th shuttle flight there was a leak and fire of two out of three of the APUs right at touchdown. Had that happened much earlier during entry it could have easily resulted in loss of the crew and vehicle. Not to mention the many near-misses with the problem that ultimately doomed Challenger.

by csixty4 11y ago

InclinedPlane 11y ago

There was no shortage of foam/ice strikes with the older foam either. STS-27 in 1988 sustained very severe tile damage from a foam strike during liftoff (around 700 tiles were damaged, including some which were completely destroyed), which resulted in partial melting of some of the airframe components during re-entry. They lucked out in that the strike was on the more durable part of the vehicle, if it had hit the leading edge as happened to Columbia the vehicle likely would have met the same fate.

mikeash 11y ago
That's crazy. And yet it looks like nothing was done afterwards to prevent it from happening again? What was wrong with them over there?
- InclinedPlane 11y ago
  It didn't destroy the vehicle so the importance of it was downplayed. It was thought, even up to the time of the Columbia disaster, that the reinforced carbon-carbon composites on the wing leading edges were too strong to take damage from a foam/ice strike. And there were contingencies in place for foam damage, though the system was overall resilient enough to take a fair bit of damage without causing a loss of the vehicle during re-entry. So to some extent they thought they had their bases covered, though in reality that was just a fantasy. The reality was that it was extremely difficult to assess any damage to the thermal protective system while on orbit, there weren't actually any feasible options for repairs of major damage, there weren't proper contingencies for a rescue operation except when the orbiter visited the station (and then only just barely), and the wing leading edge material turned out to be far more brittle than had been modeled. The whole history of the Shuttle system is a history of dodging disaster left and right and then hitting it after leaning too heavily on luck for too long. The very first flight of the Shuttle involved an "anomaly" during launch which the crew said would have resulted in them attempting to ditch if they had known about it during liftoff. On the 9th shuttle flight there was a leak and fire of two out of three of the APUs right at touchdown. Had that happened much earlier during entry it could have easily resulted in loss of the crew and vehicle. Not to mention the many near-misses with the problem that ultimately doomed Challenger.