I've heard on the grapevine here in Boulder that Apollo 13's infamous tank, when being transferred between Beech Aircraft and Rockwell, was dropped about a foot. Beech Aircraft wanted to scrap the whole tank and red tagged it, but were overruled by project managers at NASA since they couldn't point to anything wrong in some tests of the tank.
>In October 1968, the Number 2 tank eventually used on Apollo 13 was at the North American Aviation plant in Downey, California. There, technicians who were handling the tank accidentally dropped it about two inches. After testing the tank, they concluded the incident hadn't caused any detectable damage.
>The dropped tank was eventually cleared for flight and installed in Apollo 13. The tank passed all of its routine prelaunch tests. But at the end of March 1970, after a practice session called the Countdown Demonstration Test, ground crews tried to empty the tank -- and couldn’t.
>The small tube used to fill and empty the tank of its super-cold contents had been damaged by the mishandling almost two years earlier.
Looks like it was two problems that came together. The heating insulation / voltage-change oversight wouldn't have triggered unless they also had to work around the jammed pipe.
That's more or less consistent with what I've heard, with the added part that the Beech Aircraft engineers who designed the thing never wanted it to make it's way into a spacecraft. Their opinion was there was no way to certify the thing again; it wasn't designed to be serviced, so NASA would just have to wait for the next tank and delay the Apollo program. The stupid hacks all pointed to finding existing damage from the drop that had been missed when NASA's engineers tried to re-cert the tank that Beech wouldn't.
But hey PMs feeling pressure on timelines will ignore engineers' recommendations, roll the dice and just push to prod anyway. And find some engineers who'll back them up who had nothing to do with the original design. Some things never change.
I read a really interesting article on this in my undergraduate software engineering course (an excerpt from Tufte's excellent "Visual Explanations" book dealing with the shuttle Challenger mishap).
The main takeaway was not that it was malicious management, but rather that the _way the information was portrayed_ (slides) did a remarkably poor job of showing the relationship between temperature and booster failure. No one showed management a graph of, _"Here's a chart of failures vs temperature, and this is how cold is is today ..."_
Looking at the memos and slides that were presented up the chain, it's not very surprising that the correlation between temperature and failure was lost on its way up the bureaucracy.
Any reading of Tufte's claims about the Challenger launch decision should be accompanied by reading this article, one of whose authors is Roger Boisjoly, one of the Thiokol engineers who recommended against the launch:
tl/dr: Tufte's analysis itself exemplifies the charge Tufte makes. Tufte presents the wrong information about the way the decision was made, in the wrong way, and that is what drives his conclusions. When the right information is presented in the right way, it is clear that the Thiokol engineers did everything they possibly could, and that it was indeed a case of management overruling good recommendations by engineers.
The article also gives very important background information: Thiokol had previously recommended grounding the Shuttle until issues with the O-rings that had surfaced on previous flights could be understood. NASA refused. So during the discussion the night before the Challenger launch, Thiokol could not make a number of arguments that would have seemed simpler and easier, taken in isolation--because they had already made those arguments and had them rejected.
Exactly this, speaking from personal experience, a PM's job is to make sure things are shipped, not escalate Engineering problems to increasingly non-technical people up in the chain.
If engineering says "This is a bad idea", PMs will say "It's not perfect", for management that means "ship it".
> Looking at the memos and slides that were presented up the chain, it's not very surprising that the correlation between temperature and failure was lost on its way up the bureaucracy.
One of the points made by the article by Boisjoly et al (linked to in my other comment just now) is that "the correlation between temperature and failure" is hindsight (and incorrect hindsight at that--see below). On the night before the Challenger launch, nobody knew exactly what the problem was. That was not for lack of trying on the engineers' part: they had repeatedly requested more data and more experiments with the O-rings, and been refused.
The basis of the engineers' recommendation the night before the Challenger launch (which, as I noted in my previous comment, must be considered in the light of the fact that they had already recommended grounding the Shuttle until the O-ring issue could be understood, and been refused) was not "the O-rings will fail in sufficiently cold weather"; there was not sufficient data to show that. The basis was that, in the absence of an actual understanding of the issue with the O-rings, no launch should be attempted outside the range of temperatures previously experienced.
The reason "correlation between temperature and failure" is not correct hindsight is simple: as noted in the Boisjoly et al article, both test data and flight data had shown failures of the O-ring assembly at higher temperatures as well as lower temperatures! To understand how this could be, one needs to understand the root problem with the O-ring assembly (another item that Tufte's analysis gets wrong). The root problem is that, as the SRB fires, the gap between sections, which is supposed to be sealed by the O-ring assembly, expands. The O-ring assembly also has to expand, fast enough to keep the gap sealed; if it doesn't, hot gas can escape.
It is true that the speed at which the O-ring assembly can expand gets slower as the O-rings get colder. However, it is also true, looking at the data, that even at temperatures as high as 75 F (and possibly as high as 100 F--the data is not conclusive), the O-rings already were not expanding fast enough to keep the gap sealed! In other words, based on a proper understanding of the root problem, pretty much every Shuttle flight with this O-ring assembly was rolling the dice. And, of course, there were indications of a problem on a number of previous flights, which were raised as issues by the Thiokol engineers and ignored by NASA.
If project management honored every engineer's every desire to delay the project out of an abundance of caution, would it have launched at all? It seems doubtful that this was the only case in which they had to choose between delaying the project and accepting risk.
I love hearing about these sorts of invoices between agencies and armed services etc. I guess it is the equivalent of macabre dark humour used by emergency service personnel and medical staff - a way to cope with the daily stress and trials of the job.
Many decades ago, the US Air Force donated a B-52 to our local aviation museum. There were some issues around 'procurement of foreign military equipment' and import laws, I believe, so to get around that, the US had to issue an invoice to Australia to formalise the purchase of the aircraft. Proudly displayed in a glass case next under the nose of the huge bomber is an official US Dept. of Defence invoice. Total value $1.00 for the plane.
I'm not sure why this link is to an archive of an ancient Geocities site, given that there are a number of copies of this around. Here's the text (although the image link is broken):
