Jul 27 2005

NASA Discovers Its Limitations

Published by at 10:21 pm under All General Discussions

And they appear to be mostly PR problems. Since NASA is my day job I tend to stay away from posting about it because, to be honest, I blog to get away from work. Full disclosure, I do not work on anything related to Shuttle and therefore I get my news the same way you all do – from the news media.

But I have been watching Mark Coffey’s reactions with interest (and commenting at length on his site to his many Discovery posts) and feel I should address his last comments:

As NASA admits that it made a mistake in declaring the Space Shuttle fleet ready to fly again, I can’t help but go back to my question of a couple of days ago: why did we launch? What was the rush?

At the time he was referring to a waiver (though he called it ‘bending of’) the safety rules on the sticky fuel sensor. The problem with space is there is no perfection in a million plus parts exploring an unforgiving environment. But NASA keeps the odds of problems about to the level of risking your neck everyday driving the DC beltway like I do. I would rather take the risks and explore the heavens than explore Greenbelt MD – nothing against Greenbelt, where the Goddard Space Flight Center is. It’s just not as cool as being in orbit.

But this foam incident is a real conundrum for NASA – and it has nothing to do about ‘rushing’ back. It has to do with the shuttle design, and dealing with core design elements that are so expensive to correct you might as well start building the replacement system. Foam as been flying off the shuttle since it’s inception. The foam is used to insulate the Liquid O2 fuel tank (which fuels the orbiter’s main engines during lift-off) and keep the O2 chilled. That causes humidity in the air to condense and seep into the foam. So when the foam comes off it is more brick than nerf ball.

The cost to cover the foam is the issue. If you recall the very first shuttle flight, the central tank was painted white (see picture) which added immense weight and cost (cost to paint the tank, cost to fly the paint up to be thrown away with the tank). I am not sure paint would solve the flaking off problem. The shuttle creates a lot of vibrations at lift off due to its solid rocket boosters and that shakes the whole thing to the point foam can separate off into chunks. There was one idea of plastic wrap – but you run into the cost problem again. Cost to apply it, and fuel costs to take it into near orbit.

There is not an easy answer here. But understand that the foam as fallen off without incident for the life of the program with one exception, when the engineers learned their lesson about ice filled foam. That is why NASA felt there was no issue with Columbia’s foam debris that fateful flight. They had flight experience which said it shouldn’t be a problem.

Well now the opposite is true. Now they have cameras all over (which are really cool, btw) to watch separation. But things fall off and the entire world is playing armchair engineer – stating nothing can fall off a rocket when it launches.

Nice theory, not practical. Ever watch the Saturn Five launches? Note: I know the picture below is not a Saturn 5, it was the best launch pic I could find. They shed all sorts of ice. But now we have a PR expectations challenge. And we will ground the flights until NASA figures out how to deal with this mixed bag of low probability risk and a public perception it is actually an a unavoidable disaster waiting to happen.

This entire problem will only go away when the replacement systems are on line in 10 or so years. But they too will be imperfect solutions to a challenging environment we do not know very well. One that will require decades to explore and understand and become natural to us, like flying did last century.


In going to some news articles on the issue the source of the problem is (a) areas in the external tank they thought they had some solutions for or low risks from (hard to tell if it is either or both) and (b) the next shuttle launch after Columbia was slated for some redesigns of the external tank, specifically in the connection arms which were being kept warm by the foam insulation in that location (some places you cool, some places you heat – it is a very complex machine living in 1 atmosphere sea level conditions and then a few minutes later zero g, in orbit space conditions). Just wanted to clarify my assumptions with on the record facts from NASA. The point still remains, the redesign is going to cost a lot and may be hitting the point of diminishing returns.

4 responses so far

4 Responses to “NASA Discovers Its Limitations”

  1. Decision '08 says:

    More On The Shuttle, From One Who Knows Far More..

    I posted earlier on my misgivings about this latest shuttle flight…AJStrata, who’s in a far better position to know about this things, has an excellent post up that I highly recommend. You should read it all, but I’ll highlight this:


  2. baldilocks says:

    Discovery’s Foam Issues (UPDATED)

    This looks harrowing. SPACE CENTER, Houston — NASA officials said Wednesday they would ground future space shuttle flights because foam debris that brought down Columbia is still a risk. A sizable chunk of foam insulation flew off the shuttle Discover…

  3. Jeff says:

    AJ, do you know anything about a change in foam formulation due to increasingly strict environmental regs? It’s late and I can’t find the link, but I seem to recall a recent NASA administrator issuing an “executive order” that NASA would comply with international regs–I think it may have had something to do with the CFC’s in the old foam.

    I had a subconscious agreement with Mark, although my main concern is that they are subjecting a 35-year-old design to repeated launchings.

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